Effects of chronic treatment with (+)-nicotine on the stress-induced hypertension and downregulation of central nicotinic receptors in rats: comparative study with (-)-nicotine.
The effects of chronic treatment with (+)-nicotine on the immobilization stress-induced changes in blood pressure, body weight, and [3H]cytisine binding to brain nicotinic receptors were examined in rats and were compared with those of (-)-nicotine. Immobilization stress (2 hr/day(-1), for 2 weeks) induced a moderate elevation of blood pressure, loss of body weight gain, and downregulation of [3H]cytisine binding sites in cerebral cortex and midbrain. Chronic treatment with (+)- or (-)-nicotine inhibited the stress-induced hypertension but did not suppress the inhibition of body weight gain by stress. Body weight before stress load was also reduced by (-)-nicotine but not (+)-nicotine treatment. Treatment with each isomer increased the maximum number of [3H]cytisine binding sites (Bmax) of brain stem, cerebral cortex, and hippocampus. The Bmax in midbrain was also increased by (+)-nicotine but not by (-)-nicotine. Stress-induced downregulation in cerebral cortex was inhibited by both isomers. These results suggest that (+)- and (-)-nicotine cause various effects, including anti-stress effect, on the central nervous system in rats, which are slightly different between the isomers.
Takita
M
M
Department of Pharmacology, School of Medicine, Fukui Medical University, Matsuoka, Japan.
Taniguchi
T
T
Zhu
J
J
Piao
H L
HL
Tsai
T Y
TY
Muramatsu
I
I
D000470:Alkaloids / Q000378:metabolism; D000818:Animals; D001392:Azocines; D001667:Binding, Competitive; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D015536:Down-Regulation; D005731:Ganglionic Stimulants / Q000494:pharmacology*; D006973:Hypertension / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D009538:Nicotine / Q000097:blood / Q000737:chemistry / Q000494:pharmacology*; D011807:Quinolizines; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000378:metabolism; D013237:Stereoisomerism; D013312:Stress, Physiological / Q000503:physiopathology*; D014316:Tritium; D015430:Weight Gain / Q000187:drug effects; D000093843:Quinolizidine Alkaloids
D000470:Alkaloids; D001392:Azocines; D005731:Ganglionic Stimulants; D009538:Nicotine; D011807:Quinolizines; D011978:Receptors, Nicotinic; D014316:Tritium; C004712:cytisine; D000093843:Quinolizidine Alkaloids