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 obtained by a smoker, we found the following results. The initial arrival of even a low concentration of nicotine increased the firing rate of dopaminergic neurons from the ventral tegmental area (VTA) and increased the spontaneous vesicular release of GABA from hippocampal neurons. Longer exposure to nicotine caused variable, but dramatic, desensitization of nicotine 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 activation and desensitization of nicotinic receptors in various areas of the brain. L'arrivée initiale de même une faible concentration de nicotine augmente la décharge des neurones dopaminergiques de l'aire tegmentale ventrale (VTA) et augmente la libération vésiculaire spontanée de GABA par les neurones de l'hippocampe. Une exposition prolongée à la nicotine cause une désensibilisation des récepteurs nicotiniques variable mais prononcée et diminue les effets de la nicotine.