Cardiovascular effects of synthetic substance P in several species.
In dogs anaesthetised with chloralose, infusion of synthetic substance P into the femoral artery caused marked elevation of femoral arterial blood flow which was well sustained during the infusion period. Doses less than 59 fmol/kg/min increased femoral arterial flow only, but larger doses caused transient hypotension accompanied by tachycardia. The administration of substance P by i.v. and intravertebral (i.vert.) arterial routes caused hypotension and tachycardia of similar pattern and magnitude to those produced by intrafemoral (i.f.) arterial infusion of equivalent doses. I.v. injection of substance P into rats and rabbits caused qualitatively similar cardiovascular effects to those in dogs, but higher doses were required for threshold responses. Substance P had little effect on the spontaneously beating isolated guinea-pig heart. Like many other vasodilator substances in vivo, substance P caused constriction of the isolated perfused ear vein from the rabbit. The results suggest that the major cardiovascular effect of synthetic substance P is vasodilatation and that a direct action on vascular smooth muscle is involved.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects; D004285:Dogs; D004423:Ear / Q000098:blood supply; D005260:Female; D006168:Guinea Pigs; D006439:Hemodynamics / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D013045:Species Specificity; D013373:Substance P / Q000494:pharmacology*
D013373:Substance P