Cholecystokinin octapeptide (CCK-8) injected into a cerebral ventricle induces a fever-like thermoregulatory response mediated by type B CCK-receptors in the rat.
In conscious female Wistar rats with chronic lateral cerebroventricular cannula, the thermoregulatory effects of CCK-8, ceruletide and prostaglandin E1 (PGE1) were studied. In addition, the possible involvement of type A or type B receptors of CCK-8 in thermoregulatory effects of PGE1 and CCK-8 was also investigated. In the normothermic rat an intracerebroventricular (i.c.v.) injection of CCK-8 or ceruletide induced a thermogenic response with tail-skin vasoconstriction and a resulting rise in colonic temperature (Tc). There was a significant negative correlation between the starting level of Tc and the extent of rise in Tc following an i.c.v. administration of PGE1, CCK-8 or ceruletide. Subcutaneously injected CCK-8 caused decreases in Tc in a cool ambient temperature as also described by others. The fever-like response to i.c.v. injected CCK-8 was attenuated by a CCK type B receptor blocker, but not by a CCK type A receptor blocker. Conversely, the hypothermic response to peripherally administered CCK-8 was attenuated by a type A receptor blocker, but not by a type B receptor blocker. Neither of these CCK-receptor blockers influenced the fever caused by an i.c.v. injection of PGE1. It is concluded that in normothermic rats the thermogenic response observed after i.c.v. injection of CCK-8 and ceruletide is the most likely central thermoregulatory change mediated by CCK type B receptors, while the well-known hypothermic response observed after peripheral injection of these peptides might also be explained by their direct effect on variables influencing some of the thermoregulatory effector mechanisms at the periphery.
Szelényi
Z
Z
Department of Pathophysiology, University Medical School, Pécs, Hungary.
Barthó
L
L
Székely
M
M
Romanovsky
A A
AA
D000527:Alprostadil / Q000008:administration & dosage / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001570:Benzodiazepinones / Q000008:administration & dosage / Q000494:pharmacology; D001831:Body Temperature / Q000187:drug effects; D001833:Body Temperature Regulation / Q000187:drug effects* / Q000502:physiology; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism / Q000187:drug effects; D005260:Female; D005334:Fever; D007276:Injections, Intraventricular; D010671:Phenylurea Compounds; D051381:Rats; D017208:Rats, Wistar; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000502:physiology*; D012844:Sincalide / Q000008:administration & dosage / Q000494:pharmacology*; D012881:Skin Temperature / Q000187:drug effects; D013997:Time Factors
D001570:Benzodiazepinones; D010671:Phenylurea Compounds; D011949:Receptors, Cholecystokinin; C058121:L 365260; D000527:Alprostadil; D012844:Sincalide