Movement of cellular ions during stimulation with isoproterenol in simian eccrine clear cells.
The ionic mechanism of beta-adrenergic sweating is unknown. In isolated rhesus eccrine secretory coils, K efflux was determined by an extracellular K electrode and cellular monovalent ions by X-ray microanalysis. Isoproterenol (Iso) induced a small (dose-dependent propranolol-inhibitable) K efflux followed by net K reuptake. Similar K response was seen with forskolin, theophylline, or isobutyl-methylxanthine (IBMX). The net K uptake often exceeded the net K efflux, causing a small net accumulation of K. Bumetanide (BT) and ouabain not only abolished the Iso (with or without IBMX) -induced net K uptake but increased the Iso-induced initial K efflux about threefold. BT and ouabain drastically decreased K and Cl concentrations in the clear cell (by X-ray microanalysis) only in the presence of Iso plus IBMX, suggesting that adenosine 3',5'-cyclic monophosphate (cAMP) may simultaneously stimulate both KCl efflux (by unknown mechanisms) and K reuptake (presumably by BT-sensitive cotransporters and ouabain-sensitive Na pumps). Thus the cAMP-mediated ion movement is different from the cholinergic mechanism that is characterized by the net KCl loss, cell shrinkage (Saga et al., J. Membr. Biol. 107: 13-24, 1989; Takemura et al., J. Membr. Biol. In press), and no augmentation of methacholine-induced K efflux by BT or ouabain.
Sato
K T
KT
Department of Dermatology, University of Iowa College of Medicine, Iowa City 52242.
Saga
K
K
Ohtsuyama
M
M
Takemura
T
T
Kang
W H
WH
Sato
F
F
Suzuki
Y
Y
Sato
K
K
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D002034:Bumetanide / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism; D004439:Eccrine Glands / Q000166:cytology / Q000378:metabolism*; D004577:Electron Probe Microanalysis; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D008253:Macaca mulatta; D010042:Ouabain / Q000494:pharmacology; D010477:Perfusion; D011188:Potassium / Q000378:metabolism
D002712:Chlorides; D002034:Bumetanide; D010042:Ouabain; D007545:Isoproterenol; D011188:Potassium; D015056:1-Methyl-3-isobutylxanthine