Modulation of neuropeptide expression in avian embryonic sympathetic cultures

Two distinct neuropeptide-related phenotypes are found in avian paravertebral sympathetic ganglia, corresponding to somatostatin- (SS) and vasoactive intestinal polypeptide- (VIP) expressing cells. We have detected the same cell phenotypes in cultures of embryonic quail sympathetic ganglia and have used this system to study the modulation of their expression by the environment. The cell phenotypes were identified using immunocytochemistry and induced catecholamine fluorescence and quantitative data were obtained by radioimmunoassay. Dissociation of the ganglia caused a profound increase in the expression of VIP but had no effect on SS levels. Addition of corticosterone (10(-6) M) increased the expression of SS without modifying VIP levels. In contrast, depolarization of the cells induced changes in levels of both neuropeptides. The modulation of VIP correlates with the modulation of cholinergic properties. The regulation of neuropeptide expression in the avian system shows both similarities and differences to what has been found in the mammalian system.