Contractile agonists preferentially activate CL- over K+ currents in arterial myocytes.
Simultaneous patch-clamp and Ca2+ fluorescence measurements have revealed depolarising oscillations in the membrane potential of arterial (pulmonary) myocytes in response to adenosine 5'-triphosphate (ATP) and endothelin-1 (ET-1). These oscillations (i) are due to the preferential activation of Ca(2+)-activated Cl-, over K+ currents, (ii) occur through a mechanism involving Ca2+ release from intracellular Ca2+ stores and (iii) are likely to promote constriction. These results provide a novel perspective into the relative contribution and importance of Ca2+ activated Cl- and K+ channels in controlling membrane potential of arterial smooth muscle in response to contractile agonists.
Bakhramov
A
A
University Department of Pharmacology, Oxford, United Kingdom.
Hartley
S A
SA
Salter
K J
KJ
Kozlowski
R Z
RZ
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D065101:Chloride Channel Agonists; D019332:Endothelin-1 / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects; D015221:Potassium Channels / Q000819:agonists*; D051381:Rats
D065101:Chloride Channel Agonists; D019332:Endothelin-1; D015221:Potassium Channels; D000255:Adenosine Triphosphate