Effect of galanin on isolated strips of smooth muscle from the gastrointestinal tract of chickens

The contractile effects of galanin on isolated longitudinal smooth muscle s trips of pre-crop esophagus, proventriculus, duodenum, colon, and cecum of chickens were investigated. Application of galanin (5.0-100.0 nM) evoked st rong contractions from the colon and cecum (hindgut), but evoked minimal re sponses from the pre-crop esophagus, proventriculus, and duodenum (foregut) . Previous studies have demonstrated that the central administration of gal anin stimulates food consumption in rats. Since galanin-like immunoreactivi ty is present in the chicken brain, we speculate that the central release o f galanin may increase food intake and possibly be involved in a hypothalam ic-colonic reflex modulating hindgut motility and generating a defecation. Thus, the results of this study demonstrate the presence of galanin recepto rs in the chicken gut and suggest a possible Link with their functional pre sence in the hindgut to the chicken central nervous system. J. Exp. Zool. 2 83:463-468, 1999. (C) 1999 Wiley-Liss, Inc.