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.
Pasumarthi
Ravi K
RK
Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, USA.
Reznikov
Leah R
LR
Fadel
Jim
J
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