Corticosterone reversibly alters brain alpha-bungarotoxin binding and nicotine sensitivity.
Previous studies have shown that chronic corticosterone (CCS) treatment via subcutaneous pellets elicits reduced sensitivity to many actions of nicotine in mice as well as decreased brain alpha-bungarotoxin (alpha-BTX) binding. We report here the time courses of altered sensitivity to nicotine, as measured by acoustic startle, Y-maze crossing and rearing activities, heart rate, and body temperature, and alpha-BTX binding during and after CCS treatment. CCS treatment resulted in rapid decreases in sensitivity to nicotine for four of the five responses that were measured, as well as rapid changes in alpha-BTX binding. Sensitivity to nicotine returned to control levels within 3 days following pellet removal, but alpha-BTX binding returned to control levels in most brain regions 9-11 days after pellet removal. Because the restoration of control sensitivity to nicotine occurred long before alpha-BTX binding returned to control levels, it seems likely that factors other than changes in alpha-BTX binding cause chronic CCS-induced changes in sensitivity to nicotine.
Institute for Behavioral Genetics, University of Colorado, Boulder 80309, USA.
E U
EU
Grun
J R
JR
Pauly
A E
AE
Bullock
A C
AC
Collins
D000315:Adrenalectomy; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002038:Bungarotoxins / Q000493:pharmacokinetics*; D002940:Circadian Rhythm / Q000187:drug effects; D003345:Corticosterone / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D051379:Mice; D008809:Mice, Inbred C3H; D009043:Motor Activity / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009538:Nicotine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D011863:Radioimmunoassay; D013216:Reflex, Startle / Q000187:drug effects
D002038:Bungarotoxins; D009419:Nerve Tissue Proteins; D018722:Nicotinic Agonists; D009538:Nicotine; D003345:Corticosterone