Cerebral and peripheral blood flow effects of TRH in the rat--a role of vagal nerves.
The cardiovascular effects of the IV infusion of TRH were studied in the rat. TRH tended to increase the MAP and markedly increased the CBF(tot) in the control group, in vagotomized animals and in methylatropine-pretreated rats. A marked vasodilation was noted in the pancreas, gastric mucosa, duodenum and cardiac muscle. This effect was turned to vasoconstriction, the heart excluded, in vagotomized animals. Muscarinic blockade attenuated the vasodilating effect of TRH in the duodenum and gastric mucosa. The results indicate that TRH elicits cerebral vasodilation and a partly nonmuscarinic parasympathetically mediated vasodilation in several gastrointestinal organs in parallel with a vasoconstriction which is unmasked by vagotomy.
Koskinen
L O
LO
Department of Physiology, University of Uppsala, Sweden.
D000818:Animals; D001286:Atropine Derivatives / Q000494:pharmacology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D008297:Male; D010276:Parasympatholytics / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology*; D013973:Thyrotropin-Releasing Hormone / Q000502:physiology*; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology*; D014655:Vascular Resistance / Q000502:physiology
D001286:Atropine Derivatives; D010276:Parasympatholytics; D011976:Receptors, Muscarinic; D013973:Thyrotropin-Releasing Hormone; C006649:methylatropine