Slow inactivation of cardiac L-type Ca2+ channel induced by cold acclimation of guinea pig.
نویسندگان
چکیده
Whole cell L-type Ca2+ current was recorded in ventricular myocytes dissociated from guinea pigs that were bred at ambient temperatures ranging between daily averages of 4 and 29°C. The dynamic voltage range of inactivation, as measured using 400-ms conditioning pulses and a holding potential of -40 mV, extended from -50 to -20 mV in myocytes prepared in summer. In winter, the inactivation curve was shifted to more negative potentials than in summer. Double-pulse experiments revealed that the negative shift was due to slow-inactivation kinetics. The negative shift of inactivation could be induced in myocytes prepared from animals that had been kept at 5°C for >3 wk in the summer. The negative shift in Ca2+ current inactivation could be abolished by adding guanosine 5'- O-(2-thiodiphosphate) (5 mM) to the pipette solution, but not by adding staurosporine (2 μM) or 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (100 μM) to the bath. The cold acclimation may introduce the slow inactivation of the cardiac L-type Ca2+ channel through an unknown pertussis toxin-insensitive G protein.
منابع مشابه
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Takagi, Shuichi, Yasuki Kihara, Shigetake Sasayama, and Tamotsu Mitsuiye. Slow inactivation of cardiac L-type Ca21 channel induced by cold acclimation of guinea pig. Am. J. Physiol. 274 (Regulatory Integrative Comp. Physiol. 43): R348–R356, 1998.—Whole cell L-type Ca21 current was recorded in ventricular myocytes dissociated from guinea pigs that were bred at ambient temperatures ranging betwee...
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ورودعنوان ژورنال:
- American journal of physiology. Regulatory, integrative and comparative physiology
دوره 274 2 شماره
صفحات -
تاریخ انتشار 1998