Search

1. The authors attempted to detect a possible effect of treatment with phenelzine on a physiological response to nicotine in the rat. 2. Positive findings in an animal model suggest the feasibility of more complicated experiments in animals and the possibility of studies involving human subjects. 3. Treatment of Sprague Dawley rats (n = 10) with phenelzine sulfate (15.0 mg/kg ip) every 48 hours for 14 days was associated with a 73.3% decrease in the hypothermic response to nicotine. 4. Treatment with phenelzine did not enhance the rate of elimination of nicotine. 5. The authors discuss a possible relationship between changes in nicotinic mechanisms and the therapeutic actions of drugs used to treat affective illness.

1. Chronic treatment with amitriptyline produces supersensitivity to the hypothermic effects of the muscarinic agonist oxotremorine. 2. Chronic treatment with amitriptyline also produces supersensitivity to the hypothermic effects of nicotine. 3. Oxotremorine and other naturally occurring muscarinic agonists are also nicotinic agonists. 4. Chronic treatment with amitriptyline produces time-dependent and reversible supersensitivity to the hypothermic effects of nicotine. 5. The authors assessed the possibility that the development of supersensitivity to oxotremorine following chronic treatment with amitriptyline is related to an effect of this antidepressant on a nicotinic mechanism. 6. A nicotinic receptor antagonist would blunt (though not necessarily eliminate) enhanced sensitivity to the thermic effects of oxotremorine if the nicotinic effects of the latter are significant. 7. The simultaneous administration of mecamylamine (a peripherally and centrally active nicotinic receptor antagonist) greatly augments (rather than blunts) the hypothermic response to oxotremorine. 8. The data suggest that the oxotremorine may activate a nicotinic mechanism counterbalancing its effect on a muscarinic mechanism. 9. This is consistent with previously published reports that the activation of nicotinic and muscarinic mechanisms can exert opposite effects.

1. Two but not one week of treatment with amitriptyline (AMI) produces subsensitivity to the hypothermic effects of the alpha 2 antagonist yohimbine. 2. Subsensitivity persisted for the three weeks during which it was measured following the discontinuation of AMI. 3. Two weeks of twice daily injections of saline did not alter the thermic response to this agent. 4. The results support other data indicating tricyclic antidepressants (TCAs) subsensitize alpha 2 mediated thermic changes and are consistent with reports that TCAs down-regulate alpha 2 receptors.