To determine the functional role for and the pharmacological specificity of developing gastrointestinal CCK receptors, in vitro pyloric contractility and autoradiographic CCK receptor binding were examined in pups aged 1-20 days. CCK contracted the gastroduodenal junction at all ages, while nonsulfated CCK-8 (d-CCK) was less potent. Autoradiographic studies revealed CCK binding localized to the gastroduodenal junction throughout development. MK-329, a specific type A CCK receptor antagonist, completely displaced 125I CCK-8 binding at all ages, while d-CCK displaced binding at ages at which d-CCK elicited gastroduodenal contractility. The results demonstrate a physiological role for and pharmacological specificity of neonatal gastroduodenal CCK receptors.
- Gastric emptying
- Ingestive behavior
- Neonatal rat
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience