Involvement of protein kinase A in nitric oxide stimulating effect on a BK(Ca) channel of human dermal fibroblasts.
We reported previously that a large-conductance Ca2+-activated K+ (BK(Ca)) channel constitutes a significant fraction of the K+ current in human dermal fibroblasts, and that nitric oxide (NO) increases the open-channel probability (NPo) of BK(Ca) channels via a soluble guanylate cyclase (sGC)/cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG) pathway. The purpose of this study was to investigate whether the adenylate cyclase (AC)/cAMP/protein kinase A (PKA) pathway may also be involved in NO action on BK(Ca) channels in human dermal fibroblasts. Electrophysiological single-channel recordings were performed on fifth-passage cells of human penile skin cultures. KT5720 (specific PKA inhibitor) blocked the stimulatory effect of sodium nitroprusside (NO donor) on BK(Ca) channels. By contrast, forskolin (AC activator) or 8-bromo-cAMP (cell-permeable cAMP analog) did not increase the NPo of the channel. The PKA catalytic subunit (PKAcs) alone did not increase the NPo of the channel in cell-attached and inside-out patches, however, PKAcs with cGMP increased the NPo. In contrast, PKAcs with cGMP did not increase the NPo of BK(Ca) channels with 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one pretreatment, and KT5720 pretreatment also blocked the stimulatory effect of 8-Br-cGMP. In conclusion, the present data suggest the involvement of PKA in the stimulatory effect of NO on the BK(Ca) channel in human dermal fibroblasts through cGMP.
Roh
Siyoung
S
Department of Physiology, College of Medicine, Chung-Ang University, Seoul, Korea.
Choi
Seyong
S
Lim
Inja
I
D000262:Adenylyl Cyclases / Q000378:metabolism; D000293:Adolescent; D002227:Carbazoles / Q000494:pharmacology; D002478:Cells, Cultured; D002648:Child; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D020405:Dermis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004594:Electrophysiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011758:Pyrroles / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology
D002227:Carbazoles; D004791:Enzyme Inhibitors; D007211:Indoles; D051036:Large-Conductance Calcium-Activated Potassium Channels; D020030:Nitric Oxide Donors; D011758:Pyrroles; D009599:Nitroprusside; D009569:Nitric Oxide; C057416:KT 5720; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D000262:Adenylyl Cyclases; D006152:Cyclic GMP