Differential K+ channel distribution in smooth muscle cells isolated from the pulmonary arterial tree of the rat.
Intracellular photorelease of Ca2+ demonstrated the presence of Ca(2+)-activated K+ channels in smooth muscle cells isolated from different locations of the rat pulmonary arterial tree. However, cell-free patch studies revealed marked differences in K+ channel distribution. In the main pulmonary artery the most frequently observed K+ channel was a approximately 245pS conductance Ca(2+)- and ATP-activated (KCa,ATP) channel. In small pulmonary arteries two K+ channel types predominated: the KCa,ATP channel and a approximately 185pS conductance K+ channel insensitive to intracellular Ca2+, ATP and voltage. This difference in K+ channel distribution may highlight a more complex regulatory mechanism for controlling membrane potential in small pulmonary arteries, reflecting their physiologically more important role in governing pulmonary vascular reactivity.
Albarwani
S
S
University Department of Pharmacology, Oxford, England, U.K.
Heinert
G
G
Turner
J L
JL
Kozlowski
R Z
RZ
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002462:Cell Membrane / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000302:isolation & purification / Q000502:physiology*; D011651:Pulmonary Artery / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D019789:Tetraethylammonium; D000255:Adenosine Triphosphate; D002118:Calcium