From the Second Department of Internal Medicine, Faculty of Medicine,
Kyushu University, Fukuoka, Japan.
Correspondence to Yusuke Ohya, MD, PhD, Second Department of Internal Medicine, Kyushu University, Faculty of Medicine, Maidashi 3–1-1, Higashi-ku, Fukuoka 812–82, Japan. E-mail ohya{at}intmed2.med.kyushu-u.ac.jp
Abstract—The amplitude of the
whole-cell L-type Ca2+ channel current recorded from
vascular smooth muscle cells is reportedly greater in spontaneously
hypertensive rats (SHR) than in Wistar-Kyoto rats (WKY). However, no
study has examined properties of single Ca2+ channels in
arterial cells from these strains. To further test the
hypothesis that activation of L-type Ca2+ channels in
arterial smooth muscle cells would be enhanced in SHR, we
recorded single Ca2+ channel currents in resistance
mesenteric artery cells from SHR and WKY (8 to 9 weeks of age) using a
cell-attached patch clamp technique. With 50 mmol/L
Ba2+ in the recording pipette, the depolarizing
pulse from a holding potential of -40 mV evoked the single L-type
Ca2+ channel current. Opening of the single channels was
more frequent in cells from SHR than from WKY. Single-channel
conductance (20 pS) and open time (1 ms at 0 mV) did not differ in the
two strains. The results suggest that an increased amplitude of the
whole-cell current can be attributed to the enhanced opening of single
Ca2+ channels in the arterial smooth muscle
cells from SHR compared with WKY.
© 1998 American Heart Association, Inc.
Scientific Contributions
Single L-Type Calcium Channels in Smooth Muscle Cells From Resistance Arteries of Spontaneously Hypertensive Rats
Key Words: muscle, smooth, vascular • electrophysiology • calcium channels • vascular resistance • hypertension, genetic
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