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

Abstract

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