Local a-bungarotoxinsensitive nicotinic receptors in the nucleus accumbens modulate nicotine-stimulated dopamine secretion in vivo. Neurosci 101: 369–375

Previous studies have shown that nicotinic receptors (NAChRs) accessible from the cerebral aqueduct of the brainstem medi-ate the hippocampal norepinephrine (NE) release induced by i.v. nicotine. The present study was designed to investigate the role of hippocampal NAChRs in this process. Nicotinic antag-onists were microinjected or microdialyzed into the hippocam-pus (HP) before administering nicotine (0.09 mg/kg over 60 s, i.v.) to freely moving rats. a-Bungarotoxin (0.3 nmol by micro-injection) blocked nicotine-induced hippocampal NE release by 47 % (p,.05) and abolished the effect of 0.065 mg/kg nicotine. Methyllycaconitine (1.4–5.6 mM in the dialysate) inhibited the stimulatory effect of nicotine 0.09 mg/kg by 48 to 75 % (p,.05). In contrast, mecamylamine (2.9–5.8 mM) and dihydro-b-erythroidine (7–14 mM) were completely ineffective. The role of hippocampal NAChRs was demonstrated further by selectivel