ANATOMICAL BASIS FOR INTERACTIONS OF ENKEPHALINS WITH OTHER TRANSMITTERS IN THE CNS OF A SNAIL

Immunocytochemical techniques for double staining were employed to inv estigate the morphological basis for interactions between enkephalins and other neuroactive compounds in the behavior of the gastropod mollu sc Cepaea nemoralis. Coexistence of each of the two enkephalins with F MRFamide, serotonin or GABA-like immunoreactivity was found in certain neurons in cerebral, parietal, and pedal ganglia. Tyrosine hydroxylas e-immunoreactive neurons were occasionally seen in close apposition to , but never colocalized with, the enkephalins. A comparison between th ese anatomical observations and previous behavioral studies suggests t hat in gastropod molluscs cotransmission of enkephalins with classical transmitters may, at least partly, reflect synergism of these substan ces in the control of definite behavioral programs. (C) 1995 Wiley-Lis s, Inc.