Opiates inhibit the dopaminergic enhancement of the renal response to aldosterone in the rat.

1. Both naloxone, an opiate antagonist, and levorphanol, an opiate agonist, inhibit the enhanced renal response to aldosterone produced by both l-dopa pretreatment and a high K+ diet. 2. This supports the evidence for a common mechanism of action for the enhancement of the renal response to aldosterone produced by l-dopa and a high K+ diet. Whether this mechanism is dopaminergic or opiate is uncertain. 3. The inhibition of the enhanced response, produced by l-dopa, by opiates is consistent with previous findings of displacement of 3H-dopamine from renal homogenates by opiates and supports the hypothesis that the binding sites relate to the renal response to aldosterone.