O. Salminen et L. Ahtee, The effects of acute nicotine on the body temperature and striatal dopamine metabolism of mice during chronic nicotine infusion, NEUROSCI L, 284(1-2), 2000, pp. 37-40
The effects of acute nicotine administration on body temperature and striat
al dopamine metabolism of mice during chronic subcutaneous nicotine infusio
n were investigated. On the 7th day of nicotine infusion the hypothermic ef
fect of 1 mg/kg nicotine s.c. but not that of 2 mg/kg was weakened suggesti
ng that tolerance developing to nicotine's hypothermic effect during chroni
c nicotine can be overcome by increasing the dose of nicotine. In saline-in
fused control mice 1 mg/kg nicotine increased striatal 3,4-dihydroxyphenyla
cetic acid (DOPAC) but not homovanillic acid (HVA) concentration whereas 2
mg/kg increased both DOPAC and HVA. On the 7th day of nicotine infusion DOP
AC and HVA concentrations were similar to control; and acute nicotine did n
ot increase them suggesting that nicotinic acetylcholine receptors (nAChRs)
regulating striatal dopamine metabolism were desensitized. The results sug
gest that the nAChRs mediating nicotine's effects on thermoregulation and b
rain dopamine metabolism differ. (C) 2000 Elsevier Science Ireland Ltd. All
rights reserved.