Abstract
Gastrosecretory effects of intravenous administration, and microinjection and electro-osmotic application into the lateral hypothalamus (LHA) were investigated in the case of bombesin, alone and concomitant administration with insulin or 2-deoxy-D-glucose (2-DG). Bombesin, a tetradecapeptide found in the brain and gastrointestinal tract of mammals, is a potent gastrin releasing factor. At doses below the threshold of gastric secretion, bombesin produced a decrease in latency and an increase in the amount of insulin-induced gastric acid secretion. In the LHA, microinjections and electro-osmotic applications had similar effects but did not affect secretion when given alone, yet reduced the latency and increased the amount of insulin-induced acid secretion. LHA neuronal activity was also unaffected by electro-osmotic application of bombesin alone, but this compound enhanced the excitatory effects of both insulin and/or 2-DG. Thus, the gastric secretory effects of bombesin appear to be local. This peptide modulates LHA-gastrosecretory mechanism but it is ineffective when administered alone.
