Nicotine regulates 5-HT(1A) receptor gene expression in the cerebral cortex and dorsal hippocampus

Eur J Neurosci. 2001 Mar;13(6):1267-71. doi: 10.1046/j.0953-816x.2001.01501.x.


The 5-HT(1A) receptor has previously been shown to be important in mediating the behavioural effects of nicotine. It is possible that nicotine administration might regulate the levels of 5-HT receptors in limbic and cortical regions, and such regulations may underlie adaptive responses to nicotine in the central nervous system. The effects of acute and chronic systemic (--)-nicotine administration on 5-HT(1A) receptor gene expression were measured by in situ hybridization, in the rat cerebral cortex, dorsal hippocampus and lateral septum. In the cortex, acute nicotine (0.5 mg/kg i.p.) significantly increased the expression of 5-HT(1A) receptor mRNA 2 h and 24 h after injection. Similarly, acute nicotine significantly increased 5-HT(1A) receptor mRNA in the dentate gyrus (DG), CA3 and CA1 regions of the dorsal hippocampus 2 h and 24 h after injection. Acute nicotine was without effect in the lateral septum. Chronic nicotine (0.5 mg/kg i.p; twice daily for 7 days) significantly decreased 5-HT(1A) receptor mRNA in the cortex 2 h after the final injection, but was without effect at 24 h or 72 h. Chronic nicotine caused no changes in 5-HT(1A) mRNA in the lateral septum or dorsal hippocampus. These data demonstrate that nicotine regulates 5-HT(1A) receptor gene expression in the cortex and hippocampus. The rapid regulation of expression of 5-HT(1A) receptor mRNA leads to the hypothesis that nicotine-induced 5-HT release may alter the postsynaptic sensitivity to 5-HT.

MeSH terms

  • Animals
  • Cerebral Cortex / physiology*
  • Dentate Gyrus / metabolism
  • Gene Expression / drug effects*
  • Hippocampus / physiology*
  • In Situ Hybridization
  • Male
  • Nicotine / pharmacology*
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Inbred Strains
  • Receptors, Serotonin / genetics*
  • Receptors, Serotonin, 5-HT1
  • Time Factors
  • Tissue Distribution


  • RNA, Messenger
  • Receptors, Serotonin
  • Receptors, Serotonin, 5-HT1
  • Nicotine