NICOTINE MODIFIES THE ACTIVITY OF VENTRAL TEGMENTAL AREA DOPAMINERGIC-NEURONS AND HIPPOCAMPAL GABAERGIC NEURONS

While trying to mimic the dose and time course of nicotine as it is ob tained by a smoker, we found the following results. The initial arriva l of even a low concentration of nicotine increased the firing rate of dopaminergic neurons from the ventral tegmental area (VTA) and increa sed the spontaneous vesicular release of GABA from hippocampal neurons . Longer exposure to nicotine caused variable, bur dramatic, desensiti zation of nicotinic receptors and diminished the effects of nicotine. The addictive properties of nicotine as well as its diverse effects on cognitive function could be mediated through differences in activatio n and desensitization of nicotinic receptors in various areas of the b rain. ((C)Elsevier, Paris).