title: Effect of cholinergic drugs on the concentration of intracellular free calcium of rat pituitary intermediate lobe cells.
abstract: We tested the effect of cholinergic drugs on the concentration of intracellular free calcium in rat melanotropes. Acetylcholine, muscarine, carbachol, and nicotine resulted in a significant rise in this parameter. Effect of acetylcholine was reduced by atropine (non-selective muscarinic antagonist), pirenzepine (M1 muscarinic antagonist), and 4-DAMP (M3 > M1 muscarinic antagonist), but exposure to the M1 muscarinic agonist McN-A 343 resulted in a significantly smaller calcium-response than that seen in response to acetylcholine or to muscarine. This suggests the involvement of both M1 and M3 muscarinic receptors in the acetylcholine-induced calcium-rise. On the other hand, in the presence of atropine the acetylcholine-induced calcium-rise was not eliminated: this fact indicates that nicotinic receptors are also involved in the acetylcholine-induced intracellular calcium-rise. The acetylcholine-, and nicotine-induced calcium-rise was significantly reduced in presence of the neuronal-type nicotinic antagonist, mecamylamine. This suggests the involvement of a neuronal-type nicotinic receptor in the acetylcholine-induced intracellular calcium-response. Moreover, because in a further experiment almost 80% of the cells investigated responded to muscarine as well as nicotine, we conclude that both functionally active muscarinic and nicotinic receptors are present on the same cell.
authors.affiliation: Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest.
authors.forename: Z
authors.initials: Z
authors.lastname: Némethy
authors.forename: G B
authors.initials: GB
authors.lastname: Makara
authors.forename: Z
authors.initials: Z
authors.lastname: Acs
mesh_terms: D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology*; D000367:Age Factors; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology*; D002478:Cells, Cultured; D018679:Cholinergic Agonists / Q000494:pharmacology*; D003600:Cytosol / Q000378:metabolism; D005260:Female; D008297:Male; D008544:Melanocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009116:Muscarine / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D010890:Pirenzepine / Q000494:pharmacology; D010902:Pituitary Gland / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D018679:Cholinergic Agonists; D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D018722:Nicotinic Agonists; D010880:Piperidines; D014665:Vasodilator Agents; D010890:Pirenzepine; D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride; D009538:Nicotine; D001285:Atropine; D009116:Muscarine; C042375:4-diphenylacetoxy-1,1-dimethylpiperidinium; D002217:Carbachol; D000109:Acetylcholine; D002118:Calcium