The adrenergic receptor subtypes present in frog (Rana esculenta) skin.
Frog skin transports ions and water under hormonal control. In spite of the fundamental role played by adrenergic stimulation in maintaining the water balance of the organism, the receptor subtype(s) present in the skin have not been identified yet. We measured the increase in short-circuit current (ISC, an estimate of ion transport) induced by cirazoline, clonidine, xamoterol, formoterol, or BRL 37344, in order to verify the presence of alpha1, alpha2, beta1, beta2, or beta3 receptor subtypes, respectively. Only after treatment with formoterol, BRL 37344 and, to a lesser extent, cirazoline was measured a significant increase in ISC (57%, 33.2%, and 4.7%, respectively). The formoterol and BRL 37344 concentrations producing half-maximal effect (EC50) were 1.12 and 70.1 nM, respectively. Moreover, the formoterol effect was inhibited by treatment with ICI 118551 (antagonist of beta2 receptors) while SR 59230A (antagonist of beta3 receptors) had no effect; opposite findings were obtained when the BRL 37344 stimulation was investigated. Finally, by measuring the transepithelial fluxes of 22Na+ and 36Cl-, we demonstrated that Na+ absorption is increased by activation of beta2 and beta3 and is cAMP-sensitive, whereas the Cl- secretion is only increased by activation of beta2 receptors and is cAMP- and calmodulin-sensitive.
Department of General and Environmental Physiology, University of Bari, Via Amendola 165/A, 70126 Bari, Italy.
Vito
V
Bellantuono
Giuseppe
G
Cassano
Claudio
C
Lippe
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D029845:Amphibian Proteins / Q000378:metabolism*; D000818:Animals; D002147:Calmodulin / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D003000:Clonidine / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004983:Ethanolamines / Q000494:pharmacology; D000068759:Formoterol Fumarate; D007093:Imidazoles / Q000494:pharmacology; D008564:Membrane Potentials; D011412:Propanolamines / Q000494:pharmacology; D011893:Rana esculenta / Q000378:metabolism*; D011941:Receptors, Adrenergic / Q000187:drug effects / Q000378:metabolism*; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism; D022702:Receptors, Adrenergic, beta-3 / Q000378:metabolism; D015398:Signal Transduction; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D017307:Xamoterol / Q000494:pharmacology
C097869:3-(2-ethylphenoxy)-1-(1,2,3,4-tetrahydronaphth-1-ylamino)-2-propanol oxalate; D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D029845:Amphibian Proteins; D002147:Calmodulin; D002712:Chlorides; D004983:Ethanolamines; D007093:Imidazoles; D011412:Propanolamines; D011941:Receptors, Adrenergic; D018340:Receptors, Adrenergic, alpha-1; D018343:Receptors, Adrenergic, beta-2; D022702:Receptors, Adrenergic, beta-3; C026777:ICI 118551; C057368:BRL 37344; D017307:Xamoterol; D012964:Sodium; D000242:Cyclic AMP; D003000:Clonidine; C014282:cirazoline; D000068759:Formoterol Fumarate