Action of cholecystokinin and serotonin on lateral hypothalamic neurons of rats.
Discharges of spontaneously active lateral hypothalamic neurons were extracellularly recorded during iontophoretic administration of cholecystokinin (CCK-8S) or/and serotonin (5-HT) in anesthetized rats. The main results are the following. (1) The proportion of neurons responsive to CCK-8S was 62% (61/99) and that responsive to 5-HT 42% (33/78). (2) Out of the neuronal sample, 36% were influenced by both transmitters, allowing an interaction between the two systems. (3) Co-ejection of CCK and 5-HT elicited a response in 40% of the tested neurons, which was a significantly smaller responsiveness than with separate ejection of CCK-8S. The effect resulted from a reduced number of excited neurons whereas the number of inhibitions did not change. The results show that effects of 5-HT and CCK can converge on the same neuron within the lateral hypothalamus. This might be of relevance in the regulation of feeding behavior.
Zippel
U
U
Institute of Physiology (Charité), Berlin, Germany. ursula.zippel@charite.de
Heidel
E
E
Davidowa
H
H
D000818:Animals; D002766:Cholecystokinin / Q000494:pharmacology* / Q000502:physiology; D004338:Drug Combinations; D004347:Drug Interactions; D005260:Female; D007026:Hypothalamic Area, Lateral / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology* / Q000502:physiology; D012737:Sex Factors
D004338:Drug Combinations; D012701:Serotonin; D002766:Cholecystokinin