Arginine vasopressin potentiates natriuretic effect of atrial peptide.

We investigated potentiation of atrial peptide (AP)-induced natriuresis by vasopressin in anesthetized rats. Increasing doses of vasopressin potentiated AP-induced natriuresis in a dose-dependent manner, e.g.

Influence of narcotic antagonist drugs upon nitrous oxide analgesia in mice.

Nitrous oxide produced a concentration-related suppression of phenylquinone-induced abdominal constriction in mice. This analgesic effect was significantly reduced (but not abolished) by systemic pretreatment with (-)-naloxone or naltrexone but not (+)-naloxone. Systemic pretreatment with methylnaltrexone failed to appreciably influence nitrous oxide analgesia; however, methylnatrexone, administered centrally, significantly attenuated the drug effect.