Responses to noradrenaline of portal vein strips from normotensive and spontaneously hypertensive rats.
1 Responses to noradrenaline of isolated portal vein strips from 5-7 week and 15-17 week Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) have been examined. 2 15-17 week SHR tissue exhibited a greater sensitivity (lower ED50) to noradrenaline but only at reduced Ca2+EXT levels. 3 pA2 values for the alpha-adrenoreceptor antagonists WB 4101 and prazosin were significantly lower in 5-7 week SHR consistent with some change at the adrenoreceptor level. 4 Veins from SHR relaxed more rapidly in CA2+-free saline following removal of noradrenaline than did veins from WKY. 6 D600 is a competitive antagonist of the Ca2+EXT-dependent component of the noradrenaline response but K1 values were not significantly different in SHR and WKY.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000375:Aging; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004146:Dioxanes / Q000494:pharmacology; D005711:Gallopamil / Q000494:pharmacology; D006973:Hypertension / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011169:Portal Vein / Q000503:physiopathology; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D005711:Gallopamil; C010654:(2-(2',6'-dimethoxy)phenoxyethylamino)methylbenzo-1,4-dioxane; D009638:Norepinephrine; D011224:Prazosin