Comparison of the purinergic contribution to sympathetic vascular responses in SHR and WKY rats in vitro and in vivo.
Isolated tail arteries from spontaneously hypertensive rats (SHR) were more responsive than those from Wistar-Kyoto (WKY) control rats to exogenously applied noradrenaline (NA), ATP, alpha,beta-methylene ATP (mATP), KCl and sympathetic nerve stimulation. The sympathetic contractile responses of the SHR and WKY were both reduced to 10-20% of control by alpha 1-adrenoceptor antagonism. The pressor responses to sympathetic nerve stimulation were significantly greater in the SHR than the WKY rats at all stimulation frequencies examined (1-10 Hz). There was no significant difference between SHR and WKY rats in the magnitude of pressor responses produced by i.v. administration of NA or mATP. The pressor responses to sympathetic nerve stimulation in the pithed SHR were no more resistant to alpha-adrenoceptor antagonism than those of the WKY. The results suggest that the contribution by ATP to sympathetic vasoconstriction is no greater in SHR than WKY.
Dalziel
H H
HH
Department of Physiology and Pharmacology, University of Strathclyde, Royal College, Glasgow, U.K.
Machaly
M
M
Sneddon
P
P
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000294:innervation*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011983:Receptors, Purinergic / Q000502:physiology*; D013045:Species Specificity; D013564:Sympathetic Nervous System / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; D011983:Receptors, Purinergic; D000255:Adenosine Triphosphate; D009638:Norepinephrine