Effect of intracerebroventricularly injected choline on plasma ACTH and beta-endorphin levels in conscious rats.
In the present study, we examined the effect of intracerebroventricularly injected choline on plasma ACTH (adrenocorticotrophin) and beta-endorphin levels in conscious rats. The intracerebroventricularly injection of choline (50-150 micrograms) elevated plasma ACTH levels in a dose-dependent manner. Plasma beta-endorphin levels were also significantly increased. Pretreatment of rats with mecamylamine (50 micrograms; intracerebroventricularly), the nicotinic receptor antagonist, completely inhibited the ACTH and beta-endorphin response to choline (150 micrograms; intracerebroventricularly). An antagonist of the muscarinic receptor, atropine (10 micrograms; intracerebroventricularly), failed to alter these effects. Pretreatment of rats with hemicholinium-3 (20 micrograms; intracerebroventricularly), a drug which inhibits the uptake of choline into cholinergic neurons, abolished the choline-induced increases in both plasma ACTH and beta-endorphin levels. These results indicate that choline can increase plasma concentrations of ACTH and beta-endorphin through the activation of central nicotinic acetylcholine receptors.
Savci
V
V
Department of Pharmacology, Uludag University Medical Faculty, Bursa, Turkey.
Gürün
M S
MS
Ulus
I H
IH
Kiran
B K
BK
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D002794:Choline / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007278:Injections, Spinal; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D001615:beta-Endorphin / Q000378:metabolism*
D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D002794:Choline