PMID: 8586820Sep 1, 1995Paper

Loss of maximum attenuation and receptor reserve for isoprenaline at the beta 2-adrenoceptors of the portal veins of hypertensive rats

Journal of Hypertension
S A Doggrell, A J Surman

Abstract

To test the hypothesis that vascular beta 2-adrenoceptor hyporesponsiveness in spontaneously hypertensive rats (SHR) is not induced by increased blood pressure or venous hypertrophy. We compared the attenuating effects or isoprenaline, sodium nitroprusside and verapamilon the portal veins from Wistar-Kyoto (WKY) rats and SHR. studied the effects of slowly reversible beta-adrenoceptor antagonists, bromoacetylalprenololmenthane (BAAM) and ICI 147798, on the isoprenaline responses in order to determine the affinity and fractional beta 2-adrenoceptor occupancy-response relationships for isoprenaline. The SHR portal veins did not develop hypertrophy. There was a small reduction in the sensitivity to isoprenaline and a marked reduction in the maximum attenuation of hypertension caused by isoprenaline. The sensitivity and efficacy of sodium nitroprusside and verapamil were not altered by hypertension. BAAM and ICI 147798 inhibited the isoprenaline responses and reduced the maximum attenuation to isoprenaline. In the WKY rat portal vein the dissociation constant (KA) values for isoprenaline were independent of BAAM concentration, and was 1.78 +/- 0.32 x 10(-7) mol/l. Similar isoprenaline KA values were obtained from the ICI 147798 data...Continue Reading

Citations

Feb 28, 2004·Trends in Cardiovascular Medicine·R D Feldman, R Gros
Jun 1, 2000·Journal of Smooth Muscle Research = Nihon Heikatsukin Gakkai Kikanshi·K ShimamuraS Sunano
Jul 8, 2008·European Journal of Pharmacology·Delphine HolopherneJean-Claude Desfontis

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