Kinetic properties of voltage-gated Na+ currents in rat muscular sympathetic neurons with and without adenosine triphosphate and guanosine triphosphate in intracellular solution.
Voltage-gated Na+ currents were recorded from anatomically identified postganglionic muscular sympathetic neurons without and with ATP and GTP in the intracellular solution. The main findings of the study were that cells without ATP and GTP in the intracellular solution express a higher amplitude and greater density of voltage-gated Na+ current, and their Na+ current activates faster and also inactivates faster time dependently. The current is also steady-state inactivated to a lesser degree and recovers from inactivation more slowly in cells without added ATP and GTP. These findings suggest that the presence of ATP and GTP, substrates for channel phosphorylation, changes the kinetic properties of Na+ currents.
Rola
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The Medical University of Warsaw, The Faculty of Medicine, Department of Experimental and Clinical Physiology, Krakowskie Przedmieście 26/28, Warsaw 00-927, Poland.
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D000255:Adenosine Triphosphate / Q000502:physiology*; D000818:Animals; D006160:Guanosine Triphosphate / Q000502:physiology*; D007424:Intracellular Fluid / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D009474:Neurons / Q000502:physiology; D051381:Rats; D015222:Sodium Channels / Q000502:physiology*; D017783:Superior Cervical Ganglion / Q000502:physiology; D017779:Sympathetic Fibers, Postganglionic / Q000502:physiology*
D015222:Sodium Channels; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate