Influence of adrenergic and cholinergic mechanisms in baclofen induced analgesia.

1. Baclofen induced analgesia was confirmed by means of the mouse hot plate test. 2. Physostigmine significantly increased the response to baclofen whilst neostigmine was ineffective. Baclofen analgesia was reduced by atropine. 3. The response to baclofen was increased by the administration of tolazoline, propranolol and nadolol. In contrast, the analgesic response to morphine was attenuated by the antiadrenergic drugs phenoxybenzamine, tolazoline and nadolol.