PROFILE OF β‐ADRENOCEPTORS IN FEMORAL, SUPERIOR MESENTERIC AND RENAL VASCULAR BEDS OF DOGS

Abstract

1 The homogeneity of β-adrenoceptors in femoral, superior mesenteric and renal vascular beds was investigated by the use of the regional perfusion technique in dogs. 2 Isoprenaline and salbutamol produced dose-related increases in femoral and superior mesenteric blood flow. The dose-response curves for the two agonists were parallel, but salbutamol was approximately 1/15 as potent as isoprenaline on a weight basis. 3 Isoprenaline and salbutamol increased renal blood flow in a dose-related manner. However, salbutamol was approximately 1/240 as potent as isoprenaline on a weight basis, and the slope of the dose-response curve for salbutamol was less steep than that for isoprenaline. 4 The dose-response curves to isoprenaline for increase in femoral and superior mesenteric blood flow were shifted to the right by intravenous pindolol but not by intravenous or intra-arterial practolol. 5 The dose-response curves to isoprenaline for increase in renal bood flow were shifted to the right more markedly by intravenous pindolol than by intravenous or intra-arterial practolol. 6 The results indicate that β-adrenoceptors of the renal vascular bed consist of β₁-type and β₂-type whereas the femoral and superior mesenteric vascular beds contain only β₂-adrenoceptors.