Adrenergic receptor-mediated increase of intracellular Ca2+ concentration in isolated bovine corneal epithelial cells.
1. We determined if Ca2+ is a second messenger for adrenergic receptor-effector coupling in bovine corneal epithelial cells. 2. Methoxamine (10(-5) M) selectively increased intracellular Ca2+ concentration (Cai) by 65%. This increase was only partially suppressed through the removal of extracellular Ca2+ or pretreatment with 10(-6) M verapamil. 3. The beta-adrenergic-mediated increases in Cai were entirely dependent on extracellular Ca2+. These increases were directly elicited through stimulation of adenylate cyclase because 10(-6) M isoproterenol and the active analogues of forskolin (10(-5) M) all elevated Cai. 4. Therefore, increases in Cai serve a second messenger function for alpha-1 and beta-adrenergic receptor-effector coupling.
Department of Physiology and Endocrinology, Medical College of Georgia, Augusta 30912-3000.
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Reinach
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Socci
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Keith
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Scanlon
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D005576:Colforsin / Q000494:pharmacology; D003315:Cornea / Q000166:cytology / Q000378:metabolism*; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D008729:Methoxamine / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000378:metabolism*; D015290:Second Messenger Systems; D014700:Verapamil / Q000494:pharmacology
D011941:Receptors, Adrenergic; D005576:Colforsin; D014700:Verapamil; D000262:Adenylyl Cyclases; D008729:Methoxamine; D007545:Isoproterenol; D002118:Calcium