Ciliary neurotrophic factor promotes inactivation of muscle Ca2+ channels via PKC |
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Authors: | Zaldivar Daniel García María C Sánchez Jorge A |
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Institution: | Departmento de Farmacología, Centro de Investigación y de Estudios Avanzados del I.P.N., México, DF 07360, Mexico. |
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Abstract: | The actions of the ciliary neurotrophic factor (CNTF) were assessed on adult mouse skeletal muscle L-type Ca2+ currents and on Ca2+ release from sarcoplasmic reticulum. Currents were measured with the whole cell patch clamp technique. Ca2+ signals in response to single action potentials were recorded with Fluo3-AM. CNTF (20 ng/ml) reversibly reduced the amplitude of Ca2+ channel currents by 50% within 15 min. In addition, CNTF greatly increased the rate of inactivation during depolarizing pulses and shifted the steady state inactivation curve by -12 mV. The effects of CNTF were mimicked by the PKC activator PMA and prevented by the PKC-inhibitor chelerythrine. In contrast to the effects on the Ca2+ conductance, charge movement and Ca2+ signals remained unaffected by CNTF. These results suggest that CNTF can rapidly decrease muscle Ca2+ channel currents by promoting inactivation, probably through an intracellular PKC-dependent mechanism. |
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Keywords: | Calcium channel CNTF Skeletal muscle Excitation-contraction coupling Ca2+ release PKC Current inactivation L-type channels Channel modulation Cav1 1 channels |
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