Nitric oxide enhances Ca(2+)-dependent K(+) channel activity in rat carotid body cells.
The nitric oxide (NO) donor S-nitroso-acetylpenicillamine (SNAP) enhanced Ca(2+)-dependent K(+) channel activity in rat carotid body chemoreceptor cells. Ca(2+)-dependent K(+) channel activity was enhanced by SNAP in 38% (whole-cell configuration) and 67% (cell-attached mode) of the cells tested and was not affected by intracellular Ca(2+) chelation with BAPTA-AM. Enhancement of Ca(2+)-dependent K(+) channel activity by SNAP was blocked by the cGMP-dependent protein kinase G inhibitor 8-[(4-chlorophenyl)thio]-guanosine 3',5'-cyclic monophosphothioate Rp diastereomer (Rp-8-pCPT-cGMPS). NO thus enhances Ca(2+)-dependent K(+) channel activity through cGMP-dependent protein kinase G. The NO-mediated increase in Ca(2+)-dependent K(+) channel activity is likely to alter the function of carotid body chemoreceptor cells and could explain the decreased chemosensitivity of the carotid body in response to NO released from efferent nerves or vascular endothelial cells.
Silva
Jeane M
JM
Department of Pharmacology and Toxicology, Medical College of Georgia, 1120 15th Street, Augusta, GA 30912-2300, USA.
Lewis
Deborah L
DL
D000818:Animals; D002344:Carotid Body / Q000166:cytology / Q000502:physiology*; D002614:Chelating Agents / Q000494:pharmacology; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D024681:Potassium Channels, Calcium-Activated / Q000502:physiology*; D051381:Rats; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
C090860:8-(4-chlorophenylthio)guanosine 3',5'-cyclic monophosphorothioate; D002614:Chelating Agents; D004791:Enzyme Inhibitors; C494842:Kcnma1 protein, rat; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D051036:Large-Conductance Calcium-Activated Potassium Channels; D020030:Nitric Oxide Donors; D024681:Potassium Channels, Calcium-Activated; D013873:Thionucleotides; D009569:Nitric Oxide; D004533:Egtazic Acid; D026423:S-Nitroso-N-Acetylpenicillamine; D006152:Cyclic GMP; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid