Functional expression of cholecystokinin-A receptor on ventromedial hypothalamic neurons in the immature rat brain

Abstract Cholecystokinin-8 (CCK-8) dose-dependently increased the cytosolic Ca 2+ concentration ([Ca] i ) in ventromedial hypothalamic neurons acutely dissociated from the immature rat brain. The CCK-8 response was mimicked by caerulein, but not by CCK B agonists, and was often inhibited by CCK A receptor antagonists, but rarely by CCK B receptor antagonists. The response was dependent on external Ca 2+ and Na + , and was inhibited by voltage-dependent Ca 2+ channel blockers. The results suggest that CCK-8-induced depolarization via CCK A receptors increased Ca 2+ influx through a voltage-dependent Ca 2+ channel, which in turn increased [Ca] i .