RELAXANT AND BETA-2-ADRENOCEPTOR BLOCKING ACTIVITIES OF (+/-)-, (+)-PINDOLOL AND (-)-PINDOLOL ON THE RAT ISOLATED AORTA

Abstract— The KCl contracted rat aorta is relaxed by procaterol, (±)‐,(+)‐and (—)‐pindolol. The relaxations to procaterol, but not to (±)‐pindolol, were prevented by ICI 118,551 at 10−6 M. The relaxations to (±)‐pindolol are, therefore, not due to β‐adrenoceptor agonism. At 10−7 M ICI 118,551, (±)‐, (+)‐and (‐)‐pindolol were β2‐adrenoceptor antagonists as they inhibited the relaxant responses of the aorta to procaterol. 1990 Royal Pharmaceutical Society of Great Britain