NON-OPIOID EFFECTS OF N-METHYL LEVALLORPHAN IN THE ANESTHETIZED RAT

1. 1. The effects of the quaternary opioid antagonist N-methyl levallorphan upon cardiovascular responses to non-opioid agonists has been studied in the urethane-anaesthetised rat. 2. 2. N-methyl levallorphan showed an initial nicotinic agonist effect followed by pronounced ganglion blocking activity after intravenous administration. These effects were observed at doses only 2-fold higher than those required to block cardiovascular responses to [Met]enkephalin. 3. 3. The narrow selectivity of N-methyl levallorphan makes this compound inappropriate for opioid antagonist studies where nicotinic receptors may be involved. © 1990.