title: Quantitative changes of maximum contractile response to norepinephrine in mesenteric arteries from spontaneously hypertensive rats during the development of hypertension.
abstract: Maximum contractile responses of mesenteric arterial strips from spontaneously hypertensive rats (SHR) to norepinephrine (NE) were determined at all stages of hypertension (6-30 weeks of age), and data compared with findings in normotensive Wistar-Kyoto rats (WKY). Although the maximum responses to NE in the strips from both 6- and 14-week-old SHR--that is, before and after the development of elevated blood pressure--were significantly greater than those in the strips from age-matched WKY, the ratio of the maximum contraction induced by NE to that by KCl (NE/K+ ratio) was increased only after the development of hypertension. The difference in the NE/K+ ratio was also apparent in strips of femoral artery from 14-week-old rats but not in strips of thoracic aorta. The angiotensin II/K+ ratios in the three arterial strips, which were significantly decreased with advancing age of the rats, were not significantly different between the SHR and WKY. There was a good correlation between the NE/K+ ratios in the mesenteric arterial strips and the blood pressures of both SHR and WKY. It is concluded that the NE/K+ ratio in the mesenteric arterial strips was in good agreement with the onset of hypertension in SHR.
mesh_terms: D000375:Aging; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006973:Hypertension / Q000503:physiopathology*; D066298:In Vitro Techniques; D008638:Mesenteric Arteries / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000804:Angiotensin II; D011189:Potassium Chloride; D009638:Norepinephrine