Activation of orexin neurons by acute nicotine.
The hypothalamus is a prominent central site of action of nicotine but the phenotype of nicotine-sensitive neurons in this region has not been fully described. Hypothalamic orexin neurons are important regulators of state-dependent behavior, arousal and feeding. Here, we treated rats with acute nicotine and quantitated Fos expression as a marker of neuronal activation. Nicotine increased the percentage of orexin neurons expressing Fos without a significant effect on non-orexin neurons. This effect was attenuated by the nicotinic antagonists mecamylamine and dihydro-beta-erythroidine, implicating alpha4beta2-containing nicotinic receptors. The orexin system is likely to play an important role in the coordination of physiological and behavioral responses to acute nicotine treatment.
Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, USA.
Ravi K
RK
Pasumarthi
Leah R
LR
Reznikov
Jim
J
Fadel
D000818:Animals; D004079:Dihydro-beta-Erythroidine / Q000494:pharmacology; D005731:Ganglionic Stimulants / Q000494:pharmacology; D007031:Hypothalamus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D009538:Nicotine / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology; D000068797:Orexins; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D005731:Ganglionic Stimulants; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D018733:Nicotinic Antagonists; D000068797:Orexins; D016760:Proto-Oncogene Proteins c-fos; D004079:Dihydro-beta-Erythroidine; D008464:Mecamylamine; D009538:Nicotine