title: Renal microvascular effects of vasopressin and vasopressin antagonists.
abstract: The effects of vasopressin (AVP) and vasopressin antagonists on lumen diameters of cortical afferent and efferent arterioles isolated from rabbit kidneys were examined. Over a concentration range of 10(-14) to 10(-7) M, AVP had no effect on lumen diameters of afferent arterioles, although the arterioles were responsive to norepinephrine. Similarly, addition of 10(-8) M AVP to the lumen of afferent arterioles or to the bath of arterioles pretreated with indomethacin had no effect. In contrast, AVP caused a concentration-dependent reduction of lumen diameters of efferent arterioles. AVP was approximately 100-fold more potent than norepinephrine in producing contraction of efferent arterioles. The V1-selective antagonist, [d(CH2)5Tyr(Me)]AVP, and the V1/V2-antagonist, d(CH2)5D-Tyr(Et) desGlyVAVP, inhibited the vasoconstriction produced by AVP in a concentration-dependent but noncompetitive manner. The V2-selective antagonist, [d(CH2)5D-Ile]VAVP, had no significant effect on AVP-induced vasoconstriction. We conclude that, under the in vitro conditions used, AVP selectively contracts efferent arterioles. The results provide direct evidence for a postglomerular vascular effect of AVP in the renal cortex. This activity, together with its previously described effects on the glomerulus, suggests that AVP may produce changes in glomerular function and/or peritubular forces that are involved in tubular reabsorption.
authors.affiliation: Department of Pharmacology, Smith Kline & French Laboratories, King of Prussia, Pennsylvania 19406-0939.
authors.forename: R M
authors.initials: RM
authors.lastname: Edwards
authors.forename: W
authors.initials: W
authors.lastname: Trizna
authors.forename: L B
authors.initials: LB
authors.lastname: Kinter
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000494:pharmacology*; D001158:Arteries / Q000502:physiology*; D001160:Arterioles / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D011817:Rabbits; D012079:Renal Circulation / Q000187:drug effects*; D013329:Structure-Activity Relationship
chemical_list: D001127:Arginine Vasopressin; D009638:Norepinephrine