DEVELOPMENT OF THE ENKEPHALIN-LIKE, NEUROTENSIN-LIKE AND SOMATOSTATIN-LIKE (ENSLI) AMACRINE CELLS IN THE CHICKEN RETINA

The development of the enkephalin-, neurotensin- and somatostatin-like immunoreactive (ENSLI) amacrine cells in the chicken retina has been investigated by radioimmunoassay (RIA) and immunocytochemistry (ICC). By RIA, enkephalin-like immunoreactivity (ENK-LI) was detected at embr yonic day (E) 5 at only very low levels, which gradually increased unt il E17. From E18 to E21, there was a relatively rapid increase in ENK- LI levels, and just after hatching, there was a very steep rise. By IC C, the cell bodies of the ENSLI amacrine cells were first detected in the inner nuclear layer on E18, with no immunostaining in the inner pl exiform layer (IPL). On E21, more cells were detected and processes in the IPL were visible, but detailed arborisations were not clear. On p ostnatal day (P) 1, the ENSLI amacrine cells showed a morphology simil ar to that in mature retina in both the density of cell bodies and the ramification pattern of processes. Antibodies to neurotensin and soma tostatin revealed a similar developmental pattern. Thus, the three pep tides appear to follow a similar developmental pattern in the ENSLI am acrine cells, suggesting that the three peptides respond similarly to developmental stimuli, just as they are released in parallel in respon se to physiological stimulation from mature ENSLI amacrine cells. Afte r hatching, higher levels of ENK-LI were detected by RIA and more ENSL I amacrine cell bodies and processes were detected by ICC in animals k ept in the light than in those kept in the dark. In retinas kept in th e light for 12 h, it was found that immunoreactive processes in the IP L formed strongly stained patches, but this was not observed in retina s kept in the dark for 12 h. (C) 1997 Elsevier Science B.V.