Central beta adrenoceptor mediation of the antinatriuretic response to behavioral stress in conscious dogs

JP Koepke, A Grignolo, KC Light and PA Obrist

This study examined the renal excretory response to behavioral stress (aversive conditioning) in conscious dogs during infusion of beta adrenoceptor antagonists that either readily cross, or that do not readily cross the blood-brain barrier. With saline infusion alone (n = 7), behavioral stress decreased sodium excretion (-47 +/- 7% from 345 microEq/min) and urine flow rate (-48 +/- 5% from 2.1 ml/min). In the same dogs, infusion of propranolol, which readily crosses the blood- brain barrier, abolished the sodium excretion and urine flow rate responses to behavioral stress (-2 +/- 6% from 527 microEq/min and -5 +/- 3% from 3.0 ml/min, respectively). In a different group of dogs (n = 5), infusion of timolol or oxprenolol, antagonists that cross the blood-brain barrier less readily than propranolol, did not abolish the excretory response to behavioral stress. Behavioral stress decreased sodium excretion and urine flow rate during timolol infusion (-38 +/- 6% from 452 microEq/min and -36 +/- 6% from 2.4 ml/min, respectively) and oxprenolol infusion (-25 +/- 9% from 328 microEq/min and -19 +/- 8% from 1.8 ml/min, respectively). With saline infusion alone in these same dogs, behavioral stress decreased sodium excretion (-48 +/- 7% from 316 microEq/min) and urine flow rate (-40 +/- 7% from 1.7 ml/min). Mean arterial pressure increased similarly among all conditions in this study. Since the three antagonists accumulate to a high degree in the kidney, but only propranolol abolished the excretory response to behavioral stress, renal beta adrenoceptors did not appear to mediate the excretory response.(ABSTRACT TRUNCATED AT 250 WORDS)

Volume 227, Issue 1, pp. 73-77, 10/01/1983
Copyright © 1983 by American Society for Pharmacology and Experimental Therapeutics