Nicotine induced excitation of locus coeruleus neurons is mediated via release of excitatory amino acids.
Previous electrophysiological studies have shown that systemically administered nicotine in low doses increases the firing rate of rat locus coeruleus (LC) neurons. In the present study, this action of nicotine was found to be prevented by pretreatment with kynurenic acid (1 mumol; i.c.v.). In addition, pretreatment with MK 801 effectively blocked the nicotine induced LC excitation in most neurons tested (60%) whereas the rest were left unaffected by this treatment. It is suggested that excitatory amino acids (EAA), e.g. released from nerve terminals from nucleus paragigantocellularis (PGi), indirectly mediated the effect of nicotine on LC neurons.
Engberg
G
G
Department of Pharmacology, University of Göteborg, Sweden.
D000200:Action Potentials / Q000187:drug effects; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D003986:Dibenzocycloheptenes / Q000494:pharmacology; D016291:Dizocilpine Maleate; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D007736:Kynurenic Acid / Q000494:pharmacology; D008125:Locus Coeruleus / Q000166:cytology*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology
D000596:Amino Acids; D003986:Dibenzocycloheptenes; D005971:Glutamates; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D018698:Glutamic Acid; D016291:Dizocilpine Maleate; D009538:Nicotine; D007736:Kynurenic Acid