Chronic nicotine exposure affects the normal operation of hippocampal circuits.
Evidence suggests that dopamine hyperfunction in schizophrenia blocks direct sensory information flow to CA1 pyramidal cells via the temporoammonic path. Owing to the high prevalence of smoking in schizophrenics, we examined whether nicotine modulates synaptic transmission in the temporoammonic path. Application of nicotine suppressed temporoammonic synaptic transmission as in the case of dopamine application. The suppressive effect of nicotine, however, disappeared in chronic nicotine-exposed hippocampi, suggesting the loss of nicotinic modulation of transmission in the temporoammonic path. In addition, the dopaminergic modulation of temporoammonic synaptic transmission decreased after chronic nicotine treatment. These observations suggest that chronic nicotine exposure affects the normal operation of hippocampal circuits.
Nakauchi
Sakura
S
Department of Neurobiology and Behavior, University of California, Irvine, California 92697-4550, USA.
Yamazaki
Yoshihiko
Y
Sumikawa
Katumi
K
D000818:Animals; D004079:Dihydro-beta-Erythroidine / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000528:radiation effects; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009407:Nerve Block / Q000379:methods; D009415:Nerve Net / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D010852:Picrotoxin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D004079:Dihydro-beta-Erythroidine; D004298:Dopamine; D018756:GABA Antagonists; D009538:Nicotine; D018722:Nicotinic Agonists; D010852:Picrotoxin