Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| tectoreticular pathways in the turtle, pseudemys scripta. i. morphology of tectoreticular axons. | tectoreticular projections in turtles were examined by reconstructing from serial sections axons that were anterogradely filled with horseradish peroxidase after tectal injections. three tectoreticular pathways each contain extensively collateralized axons. the crossed dorsal pathway (tbd) contains large and small caliber axons. after leaving the tectum, tbd axons emit collaterals into the ipsilateral profundus mesencephali rostralis and then give off a main rostral branch that bears secondary c ... | 1985 | 3980772 |
| renin release in turtles: effects of volume depletion and furosemide administration. | to gain insight into the phylogenetic history of mechanisms controlling renin release, we conducted studies in the freshwater turtle pseudemys scripta. maneuvers known to stimulate renin release in mammals were evoked in the turtle, and the response was compared with that in mammals. cumulative hemorrhage (30% blood vol) in anesthetized turtles failed to increase renin even though arterial pressure was reduced to 50% of control. an even more severe hemorrhage (60% blood loss) or hypotension indu ... | 1985 | 3893163 |
| steroid biosynthesis in turtle testes. | testicular metabolism of radiolabelled substrates (pregnenolone, progesterone and androstenedione) was examined in two species of turtles, pseudemys scripta and sternotherus odoratus. chemical methods (chromatography, derivative formation and crystallization) identified testosterone (in both species) and 5 alpha-androstane-3 beta,17 beta-diol (in s. odoratus) as products. tentative identifications were also made of 20 beta-hydroxypregn-4-en-3-one in both turtles. chromatographic profiles indicat ... | 1985 | 3928242 |
| prolonged diving and recovery in the freshwater turtle, pseudemys scripta--iv. effects of profound acidosis on o2 consumption in turtle vs rat (mammalian) brain and heart slices. | the oxygen consumption of rat versus turtle brain and heart slices was compared as a function of extracellular ph and temperature. at ph = 6.20 rat (mammalian) brain and heart slices show a significant depression of oxygen consumption as compared to ph = 7.50 at temperatures of both 24 degrees and 37 degrees c. in the turtle oxygen consumption in brain and heart slices was not depressed at ph = 6.20 compared to ph = 7.50 at 24 degrees c and brain oxygen consumption was not significantly differen ... | 1985 | 2863049 |
| studies on the excitability of the central program generator in the spinal cord of the terrapin pseudemys scripta elegans. | we present observations on the multicyclic scratch reflex in spinal terrapins as produced by electrical stimuli applied to the shell at the specific regions at which a mechanical stimulus produces the reflex. emgs and hip and knee movements are recorded. the responses to the electrical stimuli are similar to the responses to mechanical stimuli. there is a three phase emg pattern (stein and grossman, 1980), to which the movement pattern is related (bakker and crowe, 1982). a response may consist ... | 1985 | 2863079 |
| effects of synthetic mammalian thyrotrophin releasing hormone, somatostatin and dopamine on the secretion of prolactin and growth hormone from amphibian and reptilian pituitary glands incubated in vitro. | pituitary glands of grassfrog (rana pipiens), bullfrog (rana catesbeiana), clawed toad (xenopus laevis) and two species of terrapin (chrysemys picta and pseudemys scripta) were incubated in medium containing hypothalamic extract (he), thyrotrophin releasing hormone (trh), somatostatin, dopamine, or combinations of these treatments. prolactin and gh concentrations in the medium were determined by densitometry after polyacrylamide-gel electrophoretic separation. hypothalamic extract stimulated sec ... | 1984 | 6146654 |
| the organization of motoneurons in the turtle lumbar spinal cord. | the distribution of motoneurons in the lumbosacral spinal cord of the turtle pseudemys scripta elegans was studied by using the technique of retrograde transport of horseradish peroxidase. a total of 19 different hindlimb muscles were injected with varying amounts of horseradish peroxidase. the resulting distribution of labeled motoneurons was studied in both longitudinal and transverse sections of spinal cord. motoneurons innervating a particular hindlimb muscle are clustered in longitudinally ... | 1984 | 6207212 |
| morphology of lumbar motoneurons innervating hindlimb muscles in the turtle pseudemys scripta elegans: an intracellular horseradish peroxidase study. | motoneurons in the turtle lumbar spinal cord, electrophysiologically identified as innervating a muscle belonging to a functional group, were injected with horseradish peroxidase by electrophoresis. a total of 45 motoneurons were reconstructed from transverse sections. eleven motoneurons were identified as innervating knee extensor muscles, eight as innervating hip retractor and knee flexor muscles, 14 as supplying ankle and/or toe extensors, and 12 as innervating ankle and/or toe flexor muscles ... | 1984 | 6520242 |
| chemical structure of angiotensin in the turtle, pseudemys scripta. | the chemical structure of angiotensin generated by incubating kidney extract with homologous plasma from the turtle, pseudemys scripta, has been analyzed. the turtle angiotensin was proposed to be [asp1, val5, his9] ang i by its amino acid composition and by its fluorescent peptide mapping. it was the same structure as angiotensin i in the ox and the sheep. the n-terminal amino acid of the turtle angiotensin was not blocked, unlike that of another reptilian angiotensin found in the snake, elaphe ... | 1984 | 6714649 |
| characterization of the renin-angiotensin system in the turtle pseudemys scripta. | studies were conducted in freshwater turtles pseudemys scripta to define some characteristics of the renin-angiotensin system in this reptile. dialyzed acid-treated kidney extract (1 g tissue per ml water) produced a prolonged pressor response in unanesthetized turtles, which was eliminated by boiling the extract or by pretreating the turtle with [sar1, ile8]angiotensin ii. a rat pressor assay was employed because turtle angiotensin (ang) was bound poorly by the anti-[asp1, ile5, his9]ang i used ... | 1984 | 6377928 |
| studies on the specificity of thyroid response to pituitary glycoprotein hormones. | thyrotropins (tsh) and gonadotropins (luteinizing hormone, lh, and follicle-stimulating hormone, fsh) purified from ovine, bovine, ostrich, sea turtle, and bullfrog pituitary glands were tested for their ability to simulate the thyroid glands of four species of amphibians (three anurans and a urodele), a reptile (the slider turtle), and a bird (the cockerel). all animals tested responded specifically to mammalian, sea turtle, and ostrich thyrotropins; any thyroid-stimulating activity of the gona ... | 1984 | 6436141 |
| choline acetyltransferase-like immunoreactivity in the forebrain of the red-eared pond turtle (pseudemys scripta elegans). | choline acetyltransferase (chat) immunohistochemistry was used to map the cholinergic neurons in the forebrain of pseudemys turtles. cell bodies with chat-like immunoreactivity were seen in the septum, the nucleus of the diagonal band, and embedded within the medial and lateral forebrain bundles. the region of the medial and lateral forebrain bundles contained the greatest concentration of chat-positive neurons. virtually no chat-like immunoreactivity was seen in the areas composing the reptilia ... | 1984 | 6395936 |
| a light and fluorescence cytochemical and electron microscopic study of granule-containing cells in the intrapulmonary ganglia of pseudemys scripta elegans. | in the lung of the red-eared turtle, large numbers of intramural ganglia located in the intraparenchymal connective tissue are demonstrated. numerous cells in close proximity to the principal ganglionic neurons displayed a bright blue-white formaldehyde-induced fluorescence. microspectrofluorometric analysis revealed the presence of dopamine (da) in all cells measured. subsequent light histochemical staining of the fluorescent sections showed the da-containing cells to display argentaffinity. el ... | 1984 | 6517038 |
| efferent desensitization of auditory nerve fibre responses in the cochlea of the turtle pseudemys scripta elegans. | extracellular recordings were made from single auditory afferents in the isolated half-head of the turtle, and changes in their acoustic sensitivity were examined following electrical stimulation of the efferent fibres to the basilar papilla. short trains of efferent shocks caused a prolonged elevation of the pure tone thresholds of the auditory afferents and an abolition of their spontaneous activity. these changes could be demonstrated in a majority of recordings and without antidromic firing ... | 1984 | 6520796 |
| catecholamine- and indoleamine-containing neurons in the turtle retina. | we identified a population of presumed dopaminergic amacrine cells and populations of presumed serotonergic bipolar and amacrine cells in the retina of the turtle pseudemys scripta elegans by a combination of autoradiographic, fluorescence, and immunocytochemical techniques. antisera directed against the dopamine-synthesizing enzyme, tyrosine hydroxylase (toh), stained perikarya located at the border of inner nuclear (inl) and inner plexiform (ipl) layers. processes emitted by these cells arbori ... | 1984 | 6148363 |
| excretion rates of sulfamethoxazole and n4-acetyl-sulfamethoxazole by fresh water turtles pseudemys scripta elegans. | sulfamethoxazole and n4-acetylsulfamethoxazole are excreted by fresh water turtles pseudemys scripta elegans in a biphasic mode, characterized half-lives of 5 and 100 min. acetylation and deacetylation reactions cannot be detected below a dose of 50 mg/kg. the mass balance of the dose administered is incomplete, only 30 per cent of the dose can be recovered as parent compound and metabolite. the sulfonamides must be mainly excreted by the faeces and may be metabolized in the gastro-intestinal tr ... | 1984 | 6485242 |
| the reconnection of auditory posterior root fibers in the red-eared turtle, chrysemys scripta elegans. | the auditory portion of the eighth nerve, the posterior root, was transected in chrysemys scripta elegans. two groups of animals were allowed to survive; one for 22 days and the second for 64 days. each group was then reoperated to inject hrp into the cochlear duct and allowed to survive for an additional three days - for a total survival time of 25 days and 67 days. the 67 day survivors had hrp reaction product in the eighth nerve and the primary auditory nuclei, while the 25-day survivors did ... | 1984 | 6480526 |
| angiotensin and norepinephrine effects on isolated vascular strips from a reptile. | in order to better understand the vascular effects of angiotensin ii (aii) in lower vertebrates, the contractile responses of aortic strips from the freshwater turtle pseudemys scripta elegans were studied. circumferential strips from the left aortic arch were suspended in a tissue bath in 25 degrees c reptilian ringer's solution at ph 7.5. both [asn1,val5] aii (10(-9)-10(-5) m) and norepinephrine (ne) (10(-8)-10(-4) m) produced dose-dependent contractions. the threshold dosage for aii was betwe ... | 1984 | 6735143 |
| freeze-fracture study of the turtle lung. 2. rod-shaped particles in the plasma membrane of a mitochondria-rich pneumocyte in pseudemys (chrysemys) scripta. | in thin sections of the lung of the fresh-water turtle pseudemys (chrysemys) scripta some pneumocytes can be distinguished from the remaining pulmonary epithelial cells by a larger amount of mitochondria. in these cells the typical features of type-i and type-ii cells are absent. freeze-fracture replicas reveal rod-shaped particles in the apical plasma membrane of a small population of pneumocytes, which by cytological criteria seem to be identical with the mitochondria-rich cells observed in th ... | 1984 | 6733771 |
| characterization and quantification of peptidergic amacrine cells in the turtle retina: enkephalin, neurotensin, and glucagon. | immunocytochemical methods were used for selective labeling and characterization of amacrine cells of the turtle (pseudemys scripta elegans) retina which contained neuropeptide-like immunoreactivity (leu-enkephalin, glucagon, and neurotensin). processes of amacrine cells arborized in specific strata of the inner plexiform layer (ipl). different strata were defined in relation to the boundaries of the ipl. zero represented the strata nearest the inner nuclear layer and 100 represented the strata ... | 1983 | 6363468 |
| systemic and renal effects of angiotensin ii in the freshwater turtle pseudemys scripta elegans. | this study examined the renal and systemic effects of angiotensin ii (ang ii) in the freshwater turtle, pseudemys scripta elegans. we infused [asn1, val5]ang ii at doses of 1, 10, 100, and 500 ng x kg-1 x min-1 in conscious turtles while monitoring blood pressure, glomerular filtration rate (gfr), urine volume, and plasma and urine electrolytes. saline (0.6%) was infused for two 1-h control periods at 1 ml x kg-1 x h-1 followed by a 1-h infusion of saline with ang ii added. saline alone was then ... | 1983 | 6660329 |
| some afferent and efferent connections of the vestibular nuclear complex in the red-eared turtle pseudemys scripta elegans. | in the present study some afferent, commissural, and efferent connections of the vestibular nuclear complex in the turtle pseudemys scripta elegans were demonstrated with the hrp tracing technique. afferent projections to the vestibular nuclei were found to arise in the nucleus of the basal optic root, the interstitial nucleus of the fasciculus longitudinalis medialis, the medial and lateral cerebellar nuclei, the perihypoglossal nuclear complex, and the reticular formation. distinct commissural ... | 1983 | 6643738 |
| acetylation of sulphamethoxazole by fresh water turtles pseudemys scripta elegans. | 1983 | 6632082 | |
| functional venous admixture in the lungs of the turtle, chrysemys scripta. | pulmonary functional venous admixture was determined during forced, unidirectional ventilation with pure o2 and air. at a normal lung volume of 140 ml x kg-1, anatomical shunts (physical bypass of gas exchange surface by the blood) averaged 10% of pulmonary blood flow but it increased to 28% as lung volume declined to 30 ml x kg-1. diffusion limitation and possibly inhomogeneity in ventilation: perfusion ratio also contributed to a total functional venous admixture of about 25% at normal lung vo ... | 1983 | 6622867 |
| ultrastructure of the corpuscular nerve ending in the lymph heart of the turtle (pseudemys scripta elegans). | corpuscular nerve endings were found in the tunica externa of the lymph heart of a turtle (pseudemys scripta elegans). they consisted of axon terminals and surrounding cellular lamellae. serial thin sections of one such presumable sensory corpuscle were made and reconstructed for the three-dimensional analysis of the corpuscle, with special reference to the axon terminals. it was revealed that axon terminals ramified at several points within the corpuscle and formed varicosities of various sizes ... | 1983 | 6870488 |
| freeze-fracture study of the turtle lung. 1. intercellular junctions in the air-blood barrier of pseudemys scripta. | the air-blood barrier in the lung of the turtle pseudemys scripta was studied by means of freeze-fracture replicas in an attempt to give a detailed account on the structural organization of the intercellular junctions. between the pneumocytes, zonulae occludentes containing 4-19 strands in the apico-basal direction are present; they are considered to be physiologically very tight. in the endothelium, fasciae occludentes, i.e., discontinuous occluding junctions can be found, composed of up to 4 s ... | 1983 | 6850793 |
| a correlative light-, fluorescence- and electron-microscopic study of neuroepithelial bodies in the lung of the red-eared turtle, pseudemys scripta elegans. | neuroepithelial bodies (neb) were identified for the first time in the respiratory tract of a reptile by the use of combined morphological and histochemical methods. in the red-eared turtle, pseudemys scripta elegans, neb were found within the trabecular epithelium of the respiratory tract, mainly in the branching regions of the trabeculae. an intracellular formaldehyde-induced fluorescent compound was identified as 5-hydroxytryptamine (5-ht) by means of microspectrofluorometry. subsequent histo ... | 1983 | 6196119 |
| antigen trapping in the spleen of the turtle, chrysemys scripta elegans. | using horse-radish peroxidase (hrp)-anti-hrp immune complexes, 'antigen trapping' was studied in the spleen of the turtle, chrysemys scripta elegans. it was found that antigen-trapping cells were situated in the periellipsoidal lymphocyte sheath of the white pulp only. the antigen-trapping cells have a dendritic character and a large lobulated nucleus. carbon injections revealed that these cells do not phagocytose. the results are discussed with respect to the phylogeny of antigen-trapping cells ... | 1983 | 6840808 |
| the dark brown integumentary pigment of a barnacle (balanus eburneus). a comparative study. | a histochemical analysis involving tinctorial and solubility tests was pursued in conjunction with electron microscopy for the purpose of identifying the dark brown epidermal pigment of a barnacle (balanus eburneus) as melanin and/or ommochrome. histochemically, comparisons were made with other brown pigments located in the subcarapal epidermis of another crustacean, the fiddler crab (uca pugilator), the dorsal skin of the red-backed salamander (plethodon cinereus), the liver and testis of a sli ... | 1983 | 6874419 |
| the ascending connections of the torus semicircularis central nucleus in chrysemys scripta elegans. | horseradish peroxidase was injected into the torus semicircularis central nucleus of the red-eared turtle chrysemys scripta elegans. the following observations were made. axons originating in the central nucleus project ipsilaterally through the tectoreuniens tract to the ipsilateral nucleus reunions. a second tract leaves the central nucleus medioventrally, courses under the floor of the cerebral aqueduct and terminates as an axonal field in the contralateral central nucleus. finally, there was ... | 1983 | 6662825 |
| the retinopetal system in the turtle pseudemys scripta elegans. | injections of 125i wheat-germ agglutinin or horseradish peroxidase into the eyes of turtles labeled retrogradely cells in a mesencephalic reticular area lying between the trochlear and the isthmic nuclei. their number was small and they were found predominantly contralateral to the injected eye. these reticular neurons were not labeled following control injections into the orbital cavity and therefore are considered to project to the retina similar to correspondingly located neurons in some othe ... | 1983 | 6640619 |
| supraspinal cell populations projecting to the cerebellar cortex in the turtle (pseudemys scripta elegans). | neuronal cell populations giving rise to cerebellar projections in the turtle, pseudemys scripta elegans, were analysed following injections of horseradish peroxidase into the cerebellar cortex. the most prominent retrograde cell labeling occurred bilaterally within the caudal rhombencephalon and especially in the ventral portion of the inferior reticular field. based on the structural parameters of the labeled cells (size, dendritic tree), their location and laterality of projection, attempts w ... | 1983 | 6861928 |
| spinocerebellar projections in the turtle. observations on their origin and terminal organization. | spinocerebellar projections were studied in the turtle, pseudemys scripta elegans, by both anterograde (injections of 35s-methionine into various spinal segments) and retrograde (injections of horseradish peroxidase into the cerebellar cortex) tracing techniques. after unilateral hrp injections, labeled neurons were found on both sides of the spinal cord. the total number of retrogradely labeled spinocerebellar tract neurons was relatively small and neuronal aggregations were not observed. most ... | 1983 | 6201378 |
| primary afferent projections to the spinal cord and the dorsal column nuclear complex in the turtle pseudemys. | primary afferent projections from cervical and lumbar levels were studied in the turtle pseudemys scripta elegans. injections of radioactive amino acids, wheat germ agglutinin and horseradish peroxidase were made into the dorsal root ganglia or the spinal cord. previous reports on the terminal distribution of primary afferents within the ipsilateral segment of entry were confirmed (kusuma and ten donkelaar 1979, 1980) and additional dorsal root projections were demonstrated to the contralateral ... | 1983 | 6846858 |
| cerebellar corticonuclear projections in the red-eared turtle pseudemys scripta elegans. | in the present study the organization of the corticonuclear projections of the cerebellum in the red-eared turtle pseudemys scripta elegans was investigated. to find out whether a zonal pattern exists in the cerebellar cortex, a topological analysis was made of the purkinje cell layer of a nissl-stained series of the cerebellum. this analysis showed a distinct, longitudinally oriented zonal pattern of purkinje cells. in each cerebellar half a medial, an intermediate, and a lateral zone could be ... | 1983 | 6304155 |
| the distribution of motoneurons innervating hindlimb muscles in the terrapin pseudemys scripta elegans. | the distribution of motoneurons innervating a number of hindlimb muscles in the spinal cord of the terrapin pseudemys scripta elegans was studied by means of intramuscularly injected horseradish peroxidase (hrp). it appeared that motoneurons innervating knee extensors were localized more rostrally in the spinal cord than those innervating knee flexors and hip retractors. muscles on the dorsal side of the limb were positioned more ventrally in the ventral horn compared to motoneurons innervating ... | 1982 | 7070704 |
| distribution and structural characterization of neurons giving rise to descending spinal projections in the turtle, pseudemys scripta elegans. | descending spinal projections were investigated in the turtle pseudemys scripta elegans following injections of horseradish peroxidase and/or radioactive wheat germ agglutinin into the spinal cord at various levels. using various planes of section the cells of origin in the brainstem, cerebellum, and diencephalon were characterized according to their size, dendritic tree, and precise location. projections to levels as far caudal as the lumbar spinal cord were found to arise from medial and later ... | 1982 | 7161413 |
| organization of nucleus rotundus, a tectofugal thalamic nucleus in turtles. ii. ultrastructural analyses. | nucleus rotundus in a large, tectorecipient nucleus in the dorsal thalamus of the pond turtles pseudemys scripta and chrysemys picta. rotundal neurons form a single, morphologically homogeneous population (rainey, '79) that projects to the dorsal ventricular ridge in the telencephalon. the present paper examines the morphology of and the distribution of synapses upon rotundal neurons. astrocytes, oligodendrocytes, and neurons can be identified in both 1-micrometer sections stained with toluidine ... | 1982 | 7130452 |
| afferent connections of the cerebellum in various types of reptiles. | the origin of cerebellar afferents was studied in various types of reptiles, viz., the turtles pseudemys scripta elegans and testudo hermanni, the lizard varanus exanthematicus, and the snake python regius, with retrograde tracers (the enzyme horseradish peroxidase and the fluorescent tracer "fast blue"). projections to the cerebellum were demonstrated from the nucleus of the basal optic root, the interstitial nucleus of the fasciculus longitudinalis medialis, the vestibular ganglion, and the ve ... | 1982 | 7107986 |
| phi, contractility and ca-balance under hypercapnic acidosis in the myocardium of different vertebrate species. | the influence of hypercapnic acidosis upon the heart was examined in four vertebrate species. the co2 in the tissue bath was increased from 2.7 to 15% at 12 degrees c for flounder (platichthys flesus) and cod (gadus morhua) and from 3 to 13% at 22 degrees c for turtle (pseudemys scripta) and rainbow trout (salmo gairdneri). during hypercapnia, as previously described, there was a decline and recovery of contractility in heart strips of flounder and turtle, and a sustained decrease in cod and rai ... | 1982 | 6804589 |
| immunoreactive opsin in the pineal organ of reptiles and birds. | the presence of opsin was investigated with light microscopic immunocytochemistry in pinealocytes of reptiles and birds (emys orbicularis, pseudemys scripta elegans, lacerta agilis et viridis, gallus domesticus, columba livia, melopsittacus undulatus, serinus canaria, taeniopyga punctate). the outer segments of pinealocytes selectively bound antiopsin antibody as revealed by indirect immunocytochemical techniques, indicating the occurrence of a rhodopsin-like photopigment in these structures. th ... | 1982 | 6213109 |
| identification and distribution of neurons presumed to give rise to cerebellar climbing fibers in turtle. a retrograde axonal flow study using radioactive d-aspartate as a marker. | radioactive d-aspartate and horseradish peroxidase were injected into the cerebellar cortex in turtle, pseudemys scripta elegans. while neurons retrogradely labeled with horseradish peroxidase were found in various regions of the spinal cord and brainstem, labeled cells following aspartate injections were only observed in circumscribed regions of the caudal medulla. in rat it was recently reported that climbing fibers, but no other cerebellar afferents, were retrogradely labeled with d-aspartate ... | 1982 | 7172016 |
| signal transmission from red cones to horizontal cells in the turtle retina. | 1. intracellular recordings were made from l-type horizontal cells in the retina of the turtle pseudemys scripta elegans. the responses were evoked by 500 msec pulses of 'white' light. 2. l-type horizontal cells were classified as either, 'small receptive field' s.r.f. or 'large receptive field' l.r.f. based upon (1) receptive field size and (2) kinetics of responses to test flashes covering small and big spots. 3. constant illumination of the entire receptive field, with any intensity studied, ... | 1982 | 220415 |
| sensory transduction and neuronal transmission as related to ultrastructure and encoding of information in different labyrinthine receptor systems of vertebrates. | mechano-electric transduction and neuronal transmission were studied in sensory systems ascending from and descending to single receptor cells of the labyrinth organs in submammalian vertebrates. the animals were young crocodiles (caiman crocodilus), geckos (gekko gecko, tarentola mauritanica), and turtles (pseudemys scripta elegans, chinemys reevesii). intracellular receptor potentials from the apical region of the hair cell (or from the ciliary surface) were recorded in the ampullar, macular, ... | 1982 | 6289788 |
| mesodiencephalic and other target regions of ascending spinal projections in the turtle, pseudemys scripta elegans. | ascending spinal projections were investigated in turtle pseudemys scripta elegans following injections of radioactive amino acids into the spinal cord at various levels. experiments using s35-methionine were most successful in demonstrating various mesodiencephalic target areas. ascending projections from lumbar and cervical segments terminated predominantly in caudal and lateral reticular fields including the perihypoglossal complex. these spinal regions also projected for a lesser extent to r ... | 1982 | 7161414 |
| acid-base stress and central chemical control of ventilation in turtles. | central chemical control of ventilation in turtles, chrysemys (pseudemys) scripta, has been characterized by alterations in breathing frequency (f). to assess the effects of acid-base stress on the central ventilatory response, three groups of animals were subjected to 2 h of anoxia (98% n2-2% co2), 2 h of hypercapnia (8% co2 in air), or 2 h of anoxia plus hypercapnia (92% n2-8% co2). ventilatory responses were measured continuously, and arterial blood and cerebrospinal fluid (csf) acid-base var ... | 1982 | 6818207 |
| the morphology of the bipolar cells, amacrine cells and ganglion cells in the retina of the turtle pseudemys scripta elegans. | the morphology of the neurons that contribute to the inner plexiform layer of the retina of the turtle pseudemys scripta elegans has been studied by light microscopy of whole-mount material stained by the method of golgi. cells have been distinguished on the basis of criteria that include dendritic branching patterns, dendritic morphology, dendritic tree sizes and stratification of processes in the inner plexiform layer. many of the neurons have dendritic trees oriented parallel to and a few exh ... | 1982 | 6127731 |
| the architecture of the spleen of the red-eared slider, chrysemys scripta elegans (reptilia, testudines). | the morphology of the spleen of the red-eared slider, chrysemys scripta elegans, has been described. the outer surface of the spleen is covered by a thin fibromuscular capsule, from which a number of trabeculae extend into the parenchyma. the parenchyma of the spleen shows a definite demarcation into a red and white pulp. the white pulp is composed of two lymphoid compartments: lymphoid tissue surrounds both central arterioles and ellipsoids, forming the periarteriolar and periellipsoidal lympho ... | 1982 | 7186548 |
| light and electron microscopy of the photoreceptors in the retina of the red-eared slider, pseudemys scripta elegans. | the six different types of photoreceptor in the retina of the turtle pseudemys scripta elegans have been studied by light and electron microscopy. fresh whole-mount retina, in which the oil droplet colors of the photoreceptors could be seen, was compared with fixed tissue cut in the vertical plane. the red single cone (large red oil droplet) is largest in diameter and, in electron microscopy (em) views, has the least opaque oil droplet. it also has a vacuolated paraboloid and a cone pedicle that ... | 1982 | 7130460 |
| quantitative studies of retinal ganglion cells in a turtle, pseudemys scripta elegans: ii. size spectrum of ganglion cells and its regional variation. | recent evidence suggests that ganglion cell size and its regional variation may be an important feature of vertebrate retinas. accordingly, we have examined nissl-stained, whole-mounted pseudemys scripta retinas to determine the soma size spectrum of ganglion cells at different retinal loci. cell size histograms reveal that at any given point on the retina, a majority of ganglion cells are small (6-10 microns), and in peripheral samples there is some evidence for a second, larger size class (12- ... | 1982 | 6181104 |
| quantitative electron microscopic analysis of the optic nerve of the turtle, pseudemys. | it is estimated by means of electron microscopy that the optic nerve of the turtle pseudemys scripta elegans contains 394,900 fibers of which approximately 80% are myelinated. the total fiber count agrees well with counts obtained from electron microscopic studies on other turtle species. there are, however, differences among these species in the percentage of myelinated fibers in the optic nerve. the axon diameter distribution of the myelinated fibers (excluding myelin) has a mode at 0.87 micro ... | 1982 | 7096642 |
| circulatory mechanoreceptors in the pond turtle pseudemys scripta. | this study was undertaken to characterize cardiovascular receptors in the turtle, pseudemys scripta, with particular attention being given to neural activity changes associated with alterations in blood pressure. vagal afferent nerve traffic, synchronous with heart contractions, was recorded in anesthetized artificially ventilated turtles. action potentials, from receptors that fired regularly during each heart cycle, occurred during ventricular systole. mechanical probing and vascular occlusion ... | 1982 | 7065215 |
| connections of the small bipolar cells with the photoreceptors in the turtle. an electron microscope study of golgi-impregnated, gold-toned retinas. | the connections between photoreceptors and the small bipolar cells with a landolt club in the turtle retina (pseudemys scripta elegans) were analyzed with the electron microscope after golgi impregnation and gold toning. the dendritic tree of several bipolars was partially or completely reconstructed from continuous series of thin sections. all bipolar cells studied established both basal and invaginating junctions with cone pedicles; in invaginating junctions, their dendrites invariably ended a ... | 1982 | 6175667 |
| membrane specializations in the outer plexiform layer of the turtle retina. | the internal organization of the plasma membrane at specialized contacts in the outer plexiform layer of the turtle, pseudemys scripta elegans, was analyzed with the aid of the freeze-fracturing technique. in the invaginating synapse of cone pedicles the plasma membrane of the photoreceptor ending contains an aggregate of p-face particles, images of synaptic vesicle exocytosis, and rows of forming coated vesicles which are arranged in sequence from apex to base of the synaptic ridge. thus, freez ... | 1982 | 6276452 |
| [seasonal variations of the ultimobranchial body of the turtle (pseudemys scripta)]. | ultrastructural seasonal cyclic aspects of ultimobranchial body (c.u.b.) in fresh turtles (pseudemys scripta) are studied. the c.u.b. consists of follicles and cords. the cord cells are characterized by many secretory granules measuring approximately 180 nm with variable feature and electron density. these granules are localized in the cytoplasm close to basal laminae. the follicular cells, on the contrary, present few and large secretory granules, glycogen particles, bundle of filaments and a s ... | 1982 | 6220558 |
| [fine structure of the parathyroid gland of the fresh water turtle (pseudemys scripta)]. | the ultrastructural characteristics of parathyroid in fresh-water turtles (pseudemys scripta) are studied during the four seasons of the year. the gland parenchyma consists of chief cells organized in solid cordons. no oxifil cell is seen in turtle parathyroid. the chief cells present seasonal variations in cytoplasmatic organization. these are essentially represented by: the presence of secretory granules, cilia with centriolar apparatus and microfilaments in autumn; middle and wide lipid vacuo ... | 1982 | 6217700 |
| characterization of angiotensin pressor responses in the turtle pseudemys scripta. | studies were conducted in turtles (pseudemys scripta) to characterize vascular responses to administration of exogenous angiotensin [asp1-ile5]angiotensin ii (aii). marked pressor responses were present following aii administration (2 microgram/kg iv). the pressor response was completely blocked by concomitant administration of an analogue of aii, [sar1-ile8]aii. both alpha-receptor blockade with phenoxybenzamine or catecholamine depletion by reserpine administration reduced the pressor response ... | 1981 | 7235045 |
| growth of the turtle chrysemys scripta under constant controlled laboratory conditions. | the purpose of this study was to determine 1) growth of the turtle shell and change in weight under constant controlled laboratory conditions and 2) whether under these constant conditions there were seasonal changes. fifty unfed refrigerated eight-week-old hatchling turtles chrysemys scripta were received in october and maintained in aquaria with 16 hours of artificial light and eight hours of darkness, at 24-27 degrees c and a humidity of 30% and fed twice weekly. gross linear measurements of ... | 1981 | 7258687 |
| the cytoarchitecture of the torus semicircularis in the red-eared turtle. | the cytoarchitecture and neuronal morphology of the torus semicircularis in the red-eared turtle, chrysemys scripta elegans, were examined in nissl-stained and golgi-impregnated material. the torus semicircularis begins in the caudodorsal mesencephalon and extends rostrally and laterally to end ventrally to the tectal ventricle. the torus semicircularis consists of a central nucleus and a laminar nucleus, which is interposed between the central nucleus and the ventricle. the central nucleus can ... | 1981 | 30139190 |
| anatomical distribution of estrogen target neurons in turtle brain. | autoradiographic studies with [3h]estradiol-17 beta in red-eared turtle (pseudemys scripta elegans) show concentration and retention of radioactivity in nuclei of neurons in certain regions. accumulations of estrogen target neurons exist in the periventricular brain with relationships to ventral extensions of the forebrain ventricles, including parolfactory, amygdaloid, septal, preoptic, hypothalamic and thalamic areas, as well as the dorsal ventricular ridge, the piriform cortex, and midbrain-p ... | 1981 | 7317778 |
| atrophic gastritis in a hermann's tortoise (testudo hermanni) and two red-eared turtles (chrysemys scripta elegans). | atrophic gastritis, with concomitant pseudopyloric metaplasia, occurred in a tortoise and 2 turtles. mild gastritis, with some atrophy of gastric glands and minor loss or oxynticopeptic cells which were replaced by mucous cells, was observed in the hermann 's tortoise (testudo hermanni). chronic atrophic gastritis, characterized by inflammation and atrophy of glandular elements, with changes resembling pseudopyloric metaplasia, was seen in 2 red-eared turtles (chrysemys scripta elegans). the 3 a ... | 1981 | 7340590 |
| evidence for auditory localization ability in the turtle. | evidence is presented that the semiaquatic turtle chrysemys scripta and the terrestrial turtle terrapene carolina major can detect the direction of a tone within their sensitive area of hearing. it is further suggested that not only can these species respond behaviorally to sound without extensive manipulation but can use limited hearing in a problem-solving situation of maze learning. adult emydid turtles (5 c. scripta, 3 t. carolina) learned a y-maze with a 500-c/s signal to an invisible open ... | 1981 | 7186502 |
| electron microscope study of vertebrate liver innervation. | liver fine structure was studied in various groups of vertebrates to reveal intrahepatic nerves. nerve fibers were found in the connective tissue of the liver in all mammals, birds, and reptiles studied (japanese monkey, crab-eating monkey, rabbit, guinea pig, rat, golden hamster, pigeon, japanese quail, and turtle, pseudemys scripta). nerve fibers also made direct contact with hepatocytes in these animals except for the rat and the golden hamster. intrahepatic nerves were rare or absent in amph ... | 1981 | 7316686 |
| light- and electron-microscopic demonstration of immunoreactive opsin in the pinealocytes of various vertebrates. | an antibody to opsin isolated from rod outer segments of the frog retina was applied in light- and electron-microscopic immunocytochemical studies to the pineal organ of various vertebrates (cyprinus carpio, carassius auratus, rana esculenta, emys orbicularis, pseudemys scripta elegans, lacerta agilis and viridis. gallus domesticus, columba livia, melopsittacus undulatus, serinus canaria, taeniopyga punctata, didelphis virginiana, erinaceus roumanicus, myotis myotis, rabbit, rat, cat). | 1981 | 6458362 |
| nucleus laminaris of the torus semicircularis: projection to spinal cord in reptiles. | neurons in nucleus laminaris of the torus semicircularis were retrogradely labeled following application of horseradish peroxidase (hrp) to the cervical spinal cord in two lizards (gekko gecko and iguana iguana) and a turtle (pseudemys scripta). different patterns of cell labeling were seen among the species studied and may be related to the distinctive differences in head and body movements seen in these animals during defensive, aggressive and social behaviors. | 1981 | 6270598 |
| propriospinal fibers interconnecting the spinal enlargements in some quadrupedal reptiles. | the cells of origin, course and site of termination of long propriospinal fibers interconnecting the intumescences have been studied with the aid of the horseradish peroxidase technique, as well as with anterograde degeneration techniques, in some quadrupedal reptiles (the lizards tupinambis nigropunctatus and varanus exanthematicus, and the turtles testudo hermanni and pseudemys scripta elegans). the anterograde degeneration findings suggest that long descending propriospinal fibers from the ce ... | 1980 | 6933169 |
| baroreflex sensitivity in an amphibian, rana catesbeiana, and a reptilian, pseudemys scripta elegans. | an inverse relationship between heart rate and systematic arterial pressure is demonstrated in unanesthetized bullfrogs (rana catesbeiana) and red-eared turtles (pseudemys scripta elegans). drug-induced elevation of systemic blood pressure resulted in proportional decreases in heart rate and lengthening of the pulse interval. conversely, nitroglycerin-induced decreases in blood pressure produced compensatory increases in heart rate. this relationship in frogs is defined by y = 25.4x + 1684, and ... | 1980 | 6970247 |
| acclimation, temperature selection, and heat exchange in the turtle, chrysemys scripta. | turtles acclimated to temperatures between 3 and 19 degrees c were placed in a thermal gradient. the animals usually selected temperatures above 28 degrees c within 1 h after placement in the gradient, attaining a final thermal preferendum between 31 and 33 degrees c. turtles placed in the gradient for extended periods of time were more active during the day; the temperature selected was not related to activity or time of day. turtles were transferred from a constant temperature bath at 10 or 30 ... | 1980 | 7377383 |
| comparison of the pineal complex, retina and cerebrospinal fluid contacting neurons by immunocytochemical antirhodopsin reaction. | the presence of rhodopsin was investigated by an indirect immunocytochemical method in the pineal complex of various vertebrates (carassius auratus, cyprinus carpio, hypophthalamichthys molitrix, lucioperca lucioperca, triturus vulgaris, bombina bombina, rana esculenta, pseudemys scripta elegans, lacerta agilis et viridis, white leghorn chickens, rat), in the retina of lebistes reticulatus, lucioperca lucioperca, rana esculenta, lacerta agilis, pseudemys scripta elegans, the chicken and the rat, ... | 1980 | 7456628 |
| oxygen equilibria of ectotherm blood containing multiple hemoglobins. | complete isocapnic o2 equilibrium curves (o2ec's) and related blood-gas properties are reported for whole blood of the bullfrog (rana catesbeiana) and the aquatic turtle (pseudemys scripta) at temperatures ranging from 5 to 35 degrees c. p50's for bullfrog and turtle blood at physiological ph and 25 degrees c were 36.6 torr (ph 7.83) and 19.3 torr (ph 7.55), respectively. elevation of blood temperature significantly reduced hemoglobin oxygen affinity in both species (delta h = -8.1 and -7.8 kcal ... | 1980 | 6971463 |
| cells of origin of pathways descending to the spinal cord in some quadrupedal reptiles. | the cells of origin of pathways descending to the spinal cord have been determined in several quadrupedal reptiles, viz., the turtle pseudemys scripta elegans and testudo hermanni and the lizards tupinambis nigropunctatus and varanus exanthematicus, following a technique introduced by kuypers and maisky ('75). this technique was very effective in producing retrograde transport of hrp to a great many neurons in the hypothalamus and in the brain stem. projections from the hypothalamus (the nucleus ... | 1980 | 7419757 |
| basal ganglionic pathways to the tectum: studies in reptiles. | relations between the basal ganglia and the tectum were investigated in two different orders of reptiles: turtles (chrysemys scripta) and crocodilians (caiman crocodilus). in both species, efferents from the paleostriatal complex, a telencephalic region considered comparable to the mammalian basal ganglia on the basis of topographic, histochemical, and hodological criteria, were found to project to a prominent pretectal cell group called the dorsal nucleus of the posterior commissure (ndcp). cel ... | 1980 | 7440783 |
| ultrastructure of the tastebuds of the red-eared turtle, chrysemys scripta elegans. | the fine structure of the turtle tastebud has been examined by light, transmission, and scanning electron microscopy. it contains five types of cells on the basis of their cytological features, designated types 1,2,3,a, and b. types 1, 2, and 3 reach the taste pore, whereas types a and b are located basally. the type 2 cell has access to the tongue surface, i.e., the site of gustatory stimuli, and also synapses onto afferent nerves; it probably is a gustatory receptor cell and corresponds to the ... | 1980 | 30189715 |
| distribution of ventilation in the turtle pseudemys scripta. | spontaneously ventilating turtles, pseudemys scripta, were allowed to rebreathe 133xe to equilibrium. frequent gamma camera images were obtained and processed to allow regional evaluation of ventilation. the distribution of ventilation was markedly inhomogeneous, with washin to equilibrium most rapid in anterior lung compartments and slowest in posterior lung compartments. similarly washout from equilibrium was most rapid in anterior compartments and slowest in posterior compartments. during apn ... | 1980 | 7444225 |
| the frequency selectivity of auditory nerve fibres and hair cells in the cochlea of the turtle. | 1. the electrical responses of single auditory nerve fibres or cochlear hair cells were recorded in the isolated half-head of the turtle pseudemys scripta elegans. responses to sound stimuli presented to the tympanum could be recorded for at least 4 hr after isolation.2. impulses were recorded extracellularly from single auditory nerve fibres. for tones of suprathreshold intensity the impulses occurred with a preferred phase relation (i.e. they were phase-locked) to the cycles of the sound stimu ... | 1980 | 7463380 |
| intracellular analysis and structural correlates of the organization of inputs to ganglion cells in the retina of the turtle. | intracellular recording from the ganglion cells of the retina of the turtle pseudemys scripta elegans shows that the photoresponses are characterized by either of two reversal potentials. these have been related to the bipolar and amacrine cell inputs to ganglion cells. of the recorded ganglion cells, 33% (type a) are driven predominantly by one type of input, attributed to bipolar cells. other ganglion cells (66%, type b) receive a mixed input from bipolar and amacrine cells. type a ganglion ce ... | 1980 | 6105651 |
| photoreceptor signals at visual threshold. | electrical responses of cone photoreceptors in the retina of the freshwater turtle have been characterised for flashes and steps of light in darkness and in the presence of background light. these intracellular measurements have been combined with the behavioural increment threshold curve to yield an estimate of 5-10 muv for the signal developed in a cone when the turtle can just detect an increment flash. the signal developed when the cones under the stimulus image are dark-adapted is of intere ... | 1980 | 7360231 |
| light responses of ganglion cells in the retina of the turtle. | 1. recordings were made from single axons of 218 ganglion cells in the optic nerve of the turtle, pseudemys scripta elegans. responses to light stimuli were used to classify 182 of the cells into four functional groups.2. movement-sensitive cells (113 units) responded best to moving stimuli independent of the stimulus colour or direction of motion. their receptive fields were organized into antagonistic centres and surrounds with the same spectral sensitivity. based on their patterns of response ... | 1980 | 7381765 |
| substance p-like immunoreactivity in cerebellar mossy fibers and terminals in the red-eared turtle, chrysemys scripta elegans. | 1980 | 6158019 | |
| interactions between tectal radial cells in the red-eared turtle, pseudemys scripta elegans: an analysis of tectal modules. | the optic tectum is a major subdivision of the visual system in reptiles. previous studies have characterized the laminar pattern, the neuronal populations, and the afferent and efferent connections of the optic tectum in a variety of reptiles. however, little is known about the interactions that occur between neurons within the tectum. this study describes two kinds of interactions that occur between one major class of neurons, the radial cells, in the optic tectum of pseudemys using nissl, gol ... | 1979 | 228046 |
| organization of nucleus rotundus, a tectofugal thalamic nucleus in turtles. i. nissl and golgi analyses. | this study consists of a detailed cytoarchitectonic and golgi analysis of a major tectofugal thalamic nucleus in the red-eared turtle, pseudemys scripta elegans. neurons in nucleus rotundus have a unimodal soma size distribution and a common dendritic branching pattern. they have long dendrites which undergo sparse, dichotomous branchings and contribute to dendritic fields that cover a third to half the dimensions of the nucleus. spicules, 1-2 mu long, and complex appendages, 5-20 mu long, are f ... | 1979 | 458858 |
| the fine structure of the anterior median eminence in the turtle pseudemys scripta elegans (wied). | 1979 | 554565 | |
| effects of sustained oxygen depletion on tissue pyruvate kinase activities in the freshwater turtle, pseudemys scripta elegans. | 1. the effect of sustained (48 hr) oxygen depletion on tissue (brain, heart, skeletal muscle) pyruvate kinase (pyki) activities was examined in the pond turtle (pseudemys scripta elegans). 2. pyki activities in skeletal muscle are significantly increased (from 322 +/- 84 to 450 +/- 95) following 48 hr of tissue hypoxia. pyki activities in brain may already be elevated under ambient conditions but do not change following prolonged submersion (334 +/- 75 vs 325 +/- 77). cardiac muscle pyki is actu ... | 1979 | 318413 |
| the mechanism of spinal control of reflex hind limb movements in the terrapin pseudemys scripta elegans [proceedings]. | 1979 | 490344 | |
| mirex residues in eggs and livers of two long-lived reptiles (chrysemys scripta and terrapene carolina) in mississippi, 1970-1977. | 1979 | 519044 | |
| quantitative studies of retinal ganglion cells in a turtle, pseudemys scripta elegans. i. number and distribution of ganglion cells. | multiple pathways for the transmission of visual information from retina to brain have been described in reptiles, but little is known about their functional organization. these parallel channels begin at the retina, and we have therefore begun to study the functional organization of retinal ganglion cells in the turtle, pseudemys scripta elegans. this paper describes the numbers and distribution of cells in the ganglion cell layer. to develop criteria for the identification of ganglion cells, w ... | 1979 | 457929 |
| respiratory control and co2 conductance: temperature effects in a turtle and a frog. | the respiratory control systems of the predominantly lung-breathing turtle. pseudemys scripta, and the bimodal breathing frog, rana catesbeiana, are compared. at constant temperature, control is effected in both species primarily by pulmonary ventilation, and appears to be similar in basic organization to the mammalian system. the skin co2 exchange of the frog is largely passive and apparently under little adaptive control. co2 exchange at different temperature is analyzed by means of the conduc ... | 1978 | 307794 |
| membrane recycling in the cone cell endings of the turtle retina. | the ultrastructural effects of dark, light, and low temperature were investigated in the cone cell endings of the red-eared turtle (pseudemys scripta elegans). thin sections revealed that in dark-adapted retinas maintained at 22 degrees c, the neural processes which contact the cone cells at the invaginating synapses penetrated deeply into the photoreceptor endings. when dark-adapted retinas were illuminated for 1 h at 22 degrees c, the invaginating processes were apparently extruded from the sy ... | 1978 | 730768 |
| horizontal cells of the turtle retina. ii. analysis of interconnections between photoreceptor cells and horizontal cells by light microscopy. | criteria were established whereby the chief and accessory members of double cones, red-, green-, and blue-sensitive single cones, and rods could be distinguished from one another in 1-micrometer sections through the retinas of pseudemys scripta elegans and chelydra serpentina. criteria included the presence of absence of an oil droplet, the size, color, and radial position of the oil droplet, the size and shape of the inner and outer segments, and the shape orientation of the connection between ... | 1978 | 730848 |
| effect of dry versus wet bowl environment on pet turtles. | recently hatched, certified salmonella-free, red-eared slider turtles (pseudemys scripta elegans) were obtained from a commercial breeder. half of the turtles were kept in a traditional wet-bowl environment, whereas the other half lived in individual dry-bowl environments, except for 30 minutes each day when they were immersed in water and were fed. both groups were fed commercial turtle food. during the 26 weeks of the study, individual weight and general observations were recorded for each tur ... | 1978 | 629431 |
| activation of latent salmonella and arizona organisms by dehydration of red-eared turtles, pseudemys scripta-elegans. | salmonella and arizona organisms could not be isolated from water samples, feces, and tissues of turtles prior to the experiment. after stressing, salmonella organisms were isolated from tissues of 7 of 27 stressed turtles and from only 1 of 12 unstressed turtles. arizona organisms were isolated from 9 of 36 stressed turtles whereas results for all 12 unstressed turtles were negative. | 1978 | 637401 |
| influence of intermittent breathing on ventricular depolarization patterns in chelonian reptiles. | 1. alterations between two quite distinct patterns of epicardial depolarization are associated with the normal occurrence of intermittent lung ventilation in both lightly anaesthetized and unrestrained, conscious turtles (pseudemys scripta) and tortoises (testudo graeca). 2. during apnoea depolarization sweeps from the left to the right over the ventricular surface at a conduction velocity of 0.15 m/sec. with the onset of lung ventilation the direction of depolarization propagation over the vent ... | 1978 | 671311 |
| quantitative anatomy of the lungs of the red-eared turtle, pseudemys scripta elegans. | morphometric and sterological methods were employed to evaluate the anatomical gas-exchange potential of the lungs of the fresh-water turtle, pseudemys scripta elegans. the total lung volume and lung wet weight increase with the 1.4 power of body weight. right and left lungs are similar in size and shape, containing a tissue-free central lumen, which occupies 55 per cent of the maximally inflated lung. the remainder is parenchyma, composed of 90 per cent air and 10 per cent tissue, with an effec ... | 1978 | 741106 |
| helminth parasites of the red-eared turtle (pseudemys scripta elegans) in central arkansas. | 1978 | 739316 | |
| structure of anterior dorsal ventricular ridge in a turtle (pseudemys scripta elegans). | 1978 | 731705 | |
| bicarbonate ion transport: a mechanism for the acidification of urine in the turtle. | the uricotelic turtle pseudemys scripta acidifies the urine to a ph as low as 4 in the urinary bladder. data in this report show that the mechanism of acidification in this bladder is the transport of bicarbonate ion from lumen to serosa, and that the temperature to which the turtles are adapted prior to the in vitro experiment largely determines the direction of the transmural carbon dioxide gradient observed. this temperature effect also serves to reconcile apparently disparate data that were ... | 1978 | 24894 |
| myocardial inotrophy of co2 in water- and air-breathing vertebrates. | a negative-inotropic effect of co2 on myocardial contractility presumably occurs because increasing h+ concentration competes with ca2+ at cellular membranes and proteins. since air-breathing vertebrates have higher blood and tissue co2 concentration than water breathers the question was raised whether the cardiac cell has a modified sensitivity to co2 correlated with the evolutionary transition of vertebrates from water breathers to air breathers. the water-breathing fish, salmo gairdneri, and ... | 1978 | 629370 |
| the responses of amacrine cells to light and intracellularly applied currents. | 1. intracellular responses to light were recorded from amacrine cells in the retina of the turtle pseudemys scripta elegans. 2. the recorded responses were identified on the basis of physiological criteria reported previously (marchiafava, 1976). amacrine cells produced transient 'on' and 'off' depolarizing responses irrespective of the retinal area illuminated and of wavelength. 3. the transient depolarizing responses increased by enlarging the illuminated circle up to 120 micrometer in radius. ... | 1978 | 565815 |
| analysis of electrical noise in turtle cones. | 1. properties of the light-sensitive voltage noise in cones in the retina of the turtle, pseudemys scripta elegans, have been studied by intracellular recording.2. suppression of the noise by light was a function of the hyperpolarizing response of a cone but not of the size or pattern of illumination.3. power density spectra of the noise were fitted in many cones by the product of two lorentzians with characteristic time constants tau(1) and tau(2) averaging 40 and 7 msec respectively. the spect ... | 1977 | 592199 |
| vagal control of pulmonary vascular resistance in the turtle chrysemys scripta. | 1977 | 837291 |