Effect of intracerebroventricularly injected choline on plasma ACTH and β-endorphin levels in conscious rats

• Published in: European journal of pharmacology 1996-08, Vol.309 (3), p.275-280
• Main Authors: Savci, Vahide, Gürün, M.Sibel, Ulus, Ismail H, Kiran, Burhan K
• Format: Article
• Language: English
• Subjects: ACTH (adrenocorticotrophin); Adrenocorticotropic Hormone - metabolism; Animals; Atropine; beta-Endorphin - metabolism; Choline; Choline - pharmacology; Dose-Response Relationship, Drug; Hemicholinium-3; Injections, Spinal; Male; Mecamylamine; Rats; Rats, Wistar; β-Endorphin
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/0014-2999(96)00330-5

In the present study, we examined the effect of intracerebroventricularly injected choline on plasma ACTH (adrenocorticotrophin) and β-endorphin levels in conscious rats. The intracerebroventricularly injection of choline (50–150 μg) elevated plasma ACTH levels in a dose-dependent manner. Plasma β-endorphin levels were also significantly increased. Pretreatment of rats with mecamylamine (50 μg; intracerebroventricularly), the nicotinic receptor antagonist, completely inhibited the ACTH and β-endorphin response to choline (150 μg; intracerebroventricularly). An antagonist of the muscarinic receptor, atropine (10 μg; intracerebroventricularly), failed to alter these effects. Pretreatment of rats with hemicholinium-3 (20 μg; intracerebroventricularly), a drug which inhibits the uptake of choline into cholinergic neurons, abolished the choline-induced increases in both plasma ACTH and β-endorphin levels. These results indicate that choline can increase plasma concentrations of ACTH and β-endorphin through the activation of central nicotinic acetylcholine receptors.