Centrally injected CDP-choline increases plasma vasopressin levels by central cholinergic activation.
In the present study, both the effects of intracerebroventricular (i.c.v.) injection of cytidine-5'-diphosphate choline (CDP-choline) on plasma vasopressin levels and the choline involvement of these effects were investigated. I.c.v. administration of CDP-choline (0.5, 1.0 and 2.0 micromol) increased plasma vasopressin levels dose- and time-dependently. I.c.v. injection of equimolar dose of choline (1 micromol) produced similar vasopressin response. However equimolar dose of cytidine (1 micromol; i.c.v.), the other hydrolysis product of CDP-choline, did not affect plasma vasopressin levels. Pretreatment of rats with hemicholinium-3, neuronal high affinity choline uptake inhibitor (20 microg; i.c.v.) blocked the vasopressin response to i.c.v. CDP-choline (1 micromol). Pretreatment of rats with mecamylamine (50 microg; i.c.v.), a nonselective nicotinic receptor antagonist, abolished the increase in plasma vasopressin induced by CDP-choline while atropine (10 microg; i.c.v.), nonselective muscarinic receptor antagonist, failed to change the response. In conclusion, intracerebroventricularly injected CDP-choline can increase plasma vasopressin levels by activating central nicotinic cholinergic receptors through the activation of presynaptic cholinergic mechanisms.
Cavun
Sinan
S
Department of Pharmacology and Clinical Pharmacology, Medical Faculty, Uludag University, 16059, Bursa, Turkey.
Savci
Vahide
V
Ulus
Ismail H
IH
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D018678:Cholinergic Agents / Q000494:pharmacology; D003562:Cytidine / Q000494:pharmacology; D003566:Cytidine Diphosphate Choline / Q000008:administration & dosage / Q000494:pharmacology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006426:Hemicholinium 3 / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D018697:Nootropic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D010275:Parasympathetic Nervous System / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D017661:Receptors, Presynaptic / Q000187:drug effects; D013268:Stimulation, Chemical; D013569:Synapses / Q000187:drug effects; D014667:Vasopressins / Q000097:blood*
D018678:Cholinergic Agents; D018691:Excitatory Amino Acid Antagonists; D018727:Muscarinic Antagonists; D018733:Nicotinic Antagonists; D018697:Nootropic Agents; D017661:Receptors, Presynaptic; D014667:Vasopressins; D006426:Hemicholinium 3; D003566:Cytidine Diphosphate Choline; D003562:Cytidine; D008464:Mecamylamine; D016291:Dizocilpine Maleate; D001285:Atropine