Acute and chronic effects of nicotine on serotonin uptake in prefrontal cortex and hippocampus of rats.
We sought to investigate the effect of nicotine exposure (chronic and acute) on serotonin transporter (SERT) activity in two regions of the brain important for behavioral effects of nicotine. We first looked at the effects of chronic nicotine exposure (0.7 mg/kg nicotine, twice a day for 10 days) on [(3)H]5-HT uptake in prefrontal cortex (PFC) and hippocampus of rats. A significant increase in [(3)H]5-HT uptake was observed in synaptosomes prepared from both regions. To rule out the possibility that the increases were due to the last injection given, in a separate set of experiments a single injection of nicotine was administered the evening before sacrifice. No change in uptake occurred in either region, suggesting that the increases in uptake caused by nicotine was an effect of chronic exposure and not to an acute treatment. SERT binding studies, using prefrontocortical or hippocampal membrane preparations, revealed that chronic nicotine exposure significantly increased B(max) which correlated to an increase in SERT density. Lastly, we looked at the short-term effect of nicotine on [(3)H]5-HT uptake. Rats received a single nicotine injection 15-75 min before sacrifice. PFC synaptosomes displayed a time-dependent increase in uptake, whereas hippocampal synaptosomes showed an increase at only one time point.
D000818:Animals; D002352:Carrier Proteins / Q000187:drug effects* / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000187:drug effects* / Q000378:metabolism*; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D050486:Serotonin Plasma Membrane Transport Proteins; D013574:Synaptosomes / Q000187:drug effects; D013997:Time Factors; D014316:Tritium
D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D018722:Nicotinic Agonists; D050486:Serotonin Plasma Membrane Transport Proteins; C493232:Slc6a4 protein, rat; D014316:Tritium; D012701:Serotonin; D009538:Nicotine