Neuropeptide Y-induced constriction in small resistance vessels of skeletal muscle

摘要: Abstract The in vivo responsiveness of small arterioles and venules the rat cremaster muscle to topical administration neuropeptide Y was assessed using closed-circuit television microscopy. Male Sprague-Dawley rats were anesthetized with sodium pentobarbital (50 mg/kg) exposed increasing bath concentrations (10−10–10−7 M). Neuropeptide produced dose-dependent constrictions first ( 90±8 μ m ), second 50±6 ) third 21±4 order arterioles. Arteriolar reactivity peptide inversely related vessel diameters. Venules relatively unresponsive Y. Exposure alpha-adrenergic receptor antagonist, phentolamine (10−6 M), failed modify arteriolar constrictor responses Y, while pretreatment sympathetic neuronal blocking agent, guanethidine (10−5 a small, but significant, reduction sensitivity. These data suggest that causes constriction skeletal muscle, primarily by acting directly on vascular smooth induce contraction, not via release endogenous norepinephrine.