title: Characterization of functional nicotinic acetylcholine receptors involved in catecholamine release from the isolated rat adrenal gland.
abstract: We tried to characterize nicotinic acetylcholine receptors involved in the release of catecholamines from the rat adrenal gland. The isolated adrenal gland was retrogradely perfused via the adrenal vein with Krebs-Ringer solution at a flow rate of 0.5 ml/min. Endogenous catecholamines, adrenaline and noradrenaline, released into the perfusate were electrochemically measured using high-performance liquid chromatography. (-)-Nicotine (3 x 10(-6)-3 x 10(-5) M) evoked the release of catecholamines (adrenaline >> noradrenaline) in a concentration-dependent manner. The (-)-nicotine (10(-5) M)-induced release of catecholamines was effectively attenuated by mecamylamine (10(-7) and 10(-6) M) (a relatively selective antagonist of alpha3beta4 nicotinic receptors), but not influenced by alpha-bungarotoxin (3 x 10(-7) M) (an antagonist of alpha7 nicotinic receptors) and dihydro-beta-erythroidine (10(-5) M) (a relatively selective antagonist of alpha4beta2 nicotinic receptors). (+/-)-Epibatidine (3 x 10(-7) and 10(-6) M) (a non-selective nicotinic receptor agonist), (-)-cytisine (10(-5) and 10(-4) M) (an agonist of beta4 nicotinic receptors) and (+/-)-2-(3-pyridinyl)-1-azabicyclo(2.2.2)octane (RJR-2429) (10(-5) M) (a putative agonist of alpha3beta4 nicotinic receptors) effectively evoked the release of catecholamines (adrenaline >> noradrenaline), while (E)-N-methyl-4-(3-pyridinyl)-3-butene-1-amine (RJR-2403) (up to 10(-4) M) (a selective agonist of alpha4beta2 nicotinic receptors) had no effect. The efficacies of these agonists are as follows: (+/-) epibatidine >> RJR-2429>(-)-cytisine>(-)-nicotine >> RJR-2403. These results suggest that alpha3beta4 nicotinic receptors are involved in the release of catecholamines from the rat adrenal gland.
authors.affiliation: Department of Pharmacology, Kochi Medical School, Nankoku, Kochi, 783-8505, Japan yakotani@dtn.am400gw.kochi-ms.ac.jp
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Yokotani
authors.forename: Shoshiro
authors.initials: S
authors.lastname: Okada
authors.forename: Kumiko
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism*; D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D004837:Epinephrine / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000502:physiology*
chemical_list: D002395:Catecholamines; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D009538:Nicotine; D004837:Epinephrine