Enhancement of sensitization to nicotine-induced ambulatory stimulation by psychological stress in rats.
1. The authors investigated the influence of psychological stress (PSY-stress) on sensitization to nicotine (0.5 mg/kg, s.c.)-induced ambulatory stimulation. 2. Rats were exposed to the emotional responses of animals which received foot-shock (FS), which they, themselves, did not receive. Ten daily exposures to PSY-stress for 20 min enhanced sensitization to the nicotine-induced ambulatory stimulation compared to that in non-stress rats. 3. However, the increased serum corticosterone levels following nicotine (0.5 mg/kg, s.c.) administered 24 hr after the tenth injection of nicotine in the behavioral study was almost the same in the rats exposed to PSY-stress as compared to non-stress rats. 4. These results suggest that PSY-stress may promote sensitization to nicotine-induced ambulatory stimulation and that the combined effect of PSY-stress and nicotine would facilitate the development of sensitization to nicotine.
Kita
T
T
Department of Pharmacology, Nara Medical University, Japan.
Okamoto
M
M
Kubo
K
K
Tanaka
T
T
Nakashima
T
T
D000818:Animals; D003345:Corticosterone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D013268:Stimulation, Chemical; D013315:Stress, Psychological / Q000503:physiopathology / Q000523:psychology*
D018722:Nicotinic Agonists; D009538:Nicotine; D003345:Corticosterone