Non-genomic action of 17beta-estradiol on opening of Ca(2+)- and voltage-activated K+ channel in lacrimal acinar cells.
The effect of the sex hormone 17 beta-estradiol on the opening of Ca(2+)- and voltage-activated K+ channels (BK channels) in the basolateral plasma membrane of mouse lacrimal acinar cells was studied by patch-clamp single-channel recording and Ca(2+)-measurement using fura-2 AM. In intact cells (the cell-attached configuration) using a pipette containing a Na+ -rich solution, estradiol was added to the bath solution, which does not have direct contact with the electrically isolated areas of membrane patch from which the single-channel currents were recorded. Estradiol increased the frequency of opening of the BK channels within a few minutes after its application. The effect of estradiol on the opening of the BK channels in acinar cells in male mice was greater than that in females. In Ca(2+)-measurement using fura-2 AM, estradiol did not increase the level of intracellular Ca2+ during a 5-minute observation period. The application of estradiol with propranolol, a beta-adrenergic receptor blocker, did not increase BK channel opening. The application of estradiol with Rp-cAMPS, an inhibitor of cyclic AMP-dependent protein kinase (protein kinase A), also inhibited the increase in channel opening. The addition of a catalytic unit of protein kinase A to the inside of the excised membrane patch increased the frequency of opening of the BK channels. These results suggest that estradiol interacts with beta-adrenergic receptor on the basolateral membrane and regulates the opening of BK channels by protein phosphorylation via a cyclic AMP pathway, without a change in the Ca2+ level.
Suzuki
Kazuo
K
Department of Bio-Medical Engineering, School of High-Technology for Human Welfare, Tokai University, Japan. suzukazu@wing.ncc.u-tokai.ac.jp
Oda
Yuichi
Y
Oda
Kentaro
K
Tanaka
Sinano
S
Sakaino
Yukimi
Y
Matsudaira
Takumi
T
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects; D004357:Drug Synergism; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005456:Fluorescent Dyes; D016257:Fura-2; D007765:Lacrimal Apparatus / Q000166:cytology* / Q000502:physiology; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008856:Microscopy, Fluorescence; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects* / Q000378:metabolism; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects*; D013873:Thionucleotides / Q000494:pharmacology; D013997:Time Factors
D005456:Fluorescent Dyes; D051036:Large-Conductance Calcium-Activated Potassium Channels; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D013873:Thionucleotides; C016957:adenosine-3',5'-cyclic phosphorothioate; D004958:Estradiol; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D002118:Calcium; D016257:Fura-2