Sedative action of cholecystokinin octapeptide on behavioral excitation by thyrotropin releasing hormone and methamphetamine in the rat.
Intracerebroventricular (i.c.v.) injection of C-terminal octapeptide of cholecystokinin (CCK-8) in rats prolonged pentobarbital- and ethanol-induced sleeping time, but non-sulfated CCD-8 (CCK-8-NS) had no effect and caerulein showed a tendency to prolong the pentobarbital narcosis. On the other hand, i.c.v. injection of thyrotropin releasing hormone (TRH) shortened the sleeping time and the effect of CCK-8 was apparently antagonized by combined administration of TRH. Spontaneous locomotor activity in the late morning and early afternoon was not affected by CCK-8, but it increased following i.c.v. injection of CCK-8-NS. Hyperactivity produced by TRH and methamphetamine was suppressed by i.c.v. injection of CCK-8, while CCK-8-NS showed a tendency to enhance the methamphetamine-induced hyperactivity and caerulein had no effect. These results indicate that CCK-8 has a sedative action and antagonizes the behavioral excitation caused by TRH and methamphetamine, but that the effects of CCK-8-NS and caerulein were rather the opposite of those of CCK-8. In an additional experiment the TRH-induced body shaking response was not affected by combined administration of CCK-8.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000187:drug effects; D002108:Ceruletide / Q000494:pharmacology; D002766:Cholecystokinin / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D008694:Methamphetamine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D010424:Pentobarbital / Q000494:pharmacology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012844:Sincalide; D012890:Sleep / Q000187:drug effects; D013973:Thyrotropin-Releasing Hormone / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000494:pharmacology
D006993:Hypnotics and Sedatives; D010446:Peptide Fragments; D000431:Ethanol; D008694:Methamphetamine; D013973:Thyrotropin-Releasing Hormone; D002108:Ceruletide; D002766:Cholecystokinin; D010424:Pentobarbital; D012844:Sincalide