Influence of various drugs on the voluntary intake of nicotine by rats

The effects of the dopaminergic agonists ( L-dopa, pergolide) and antagonis ts (haloperidol, clozapin) and a cholinergic agonist (tacrine) and antagoni st (mecamylamine) on the voluntary intake of nicotine were investigated wit h the 2-bottle paradigm with the test drugs being dissolved directly in the drinking fluid of the animals. This method was found to be a reliable proc edure to quickly screen compounds with specific sites of action in the brai n for their effects on the voluntary intake of nicotine or perhaps other su bstances of abuse as well, L-dopa, pergolide and haloperidol did not affect the intake of nicotine, whereas tacrine increased it slightly and clozapin e and mecamylamine markedly, These results indicate that blockade of nicoti nic and dopaminergic D4 receptors partially reduce the desired effect of ni cotine by forcing the animals to consume more of this substance, Copyright (C) 2000 S. Karger AG, Basel.