EVIDENCE FOR THE PARTICIPATION OF β1‐ADRENOCEPTORS IN ISOPRENALINE‐INDUCED RENIN RELEASE FROM RAT KIDNEY SLICES in vitro

Abstract

1 The inhibitory effects were studied of 4 β-adrenoceptor antagonists against renin release induced by isoprenaline (0.5 m̈mol/1) in rat kidney slices. Additionally the pA₂ values of these 4 drugs were measured against isoprenaline in guinea-pig isolated atria and trachea (against β₁- and β₂-adrenoceptors respectively). 2 When employed at a concentration of 2 nmol/1 propranolol and atenolol significantly inhibited renin release (P < 0.001 and P < 0.01) whereas practolol and IPS 339 [t-butyl-amino-3 ol-2 propyl) oximino-9 fluorene] had little effect. 3 A positive correlation was shown between the degree of inhibition of renin release and the pA₂ of the antagonists at the β₁-adrenoceptors. 4 When practolol and IPS 339 were used in equipotent molar concentrations to propranolol for the β₁-adrenoceptors they inhibited renin release. 5 The results suggest that the adrenoceptor involved in the renin release induced by isoprenaline in the rat kidney is of the β₁-type.