Intraaccumbal mecamylamine infusion does not affect dopamine output in thenucleus accumbens of chronically nicotine-treated rats

Recently we have shown that the nicotinic receptor (nAChR) antagonist mecam ylamine both when administered systemically and locally into the ventral te gmental area (VTA) to chronically nicotine-treated rats reduces dopamine (D A) output in the nucleus accumbens (NAC) and elicits behavioral withdrawal signs. However, the putative contributory role of nAChRs in the NAC in medi ating these effects of systemic mecamylamine has not been clarified. Theref ore, we here investigated the effect on extracellular levels of DA in the N AC of local intraaccumbal administration of mecamylamine to chronically nic otine-treated rats and its putative behavioral correlates. In these experim ents local application of mecamylamine into the NAG, in a concentration tha t increased NAC DA levels in control rats, did not affect DA output or beha vior in the nicotine-treated animals. These results provide further support for the contention that nAChRs in the VTA, but not in the NAG, are of majo r importance for the mesolimbic DA reduction and associated behavioral sign s in nicotine withdrawal.