A CHOLECYSTOKININ-LIKE HORMONE ACTIVATES A FEEDING-RELATED NEURAL CIRCUIT IN LOBSTER

THE peptide hormone cholecystokinin (CCK) contributes to the production of feeding-related behaviour in mammals, but the mechanism by which it exerts its effects remains unclear1-6. The gastric mill neural circuit of lobster is an experimentally accessible model system for studying the hormonal control of feeding-related behaviour7, 8. Composed of 11 identified neurons, this circuit produces rhythmic movement of teeth within the stomach9. We have previously shown that the gastric mill motor pattern can be modulated by a cholecystokinin-like peptide in vitro10. We report here that (1) after feeding, levels of CCK-like peptide in haemolymph increase with the activation of the gastric mill, (2) injections of CCK activate the gastric mill, and (3) a specific CCK antagonist inhibits feeding-induced gastric mill activity. This neatly demonstrates a causal link between in vivo release of a peptide hormone and activation of a neural circuit. © 1990 Nature Publishing Group.