| cannabinoid receptors are absent in insects. | the endocannabinoid system exerts an important neuromodulatory role in mammals. knockout mice lacking cannabinoid (cb) receptors exhibit significant morbidity. the endocannabinoid system also appears to be phylogenetically ancient--it occurs in mammals, birds, amphibians, fish, sea urchins, leeches, mussels, and even the most primitive animal with a nerve network, the hydra. the presence of cb receptors, however, has not been examined in terrestrial invertebrates (or any member of the ecdysozoa) ... | 2001 | 11447587 |