Calcium currents in bullfrog sympathetic neurons. II. Inactivation.
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منابع مشابه
Calcium currents in bullfrog sympathetic neurons. II. Inactivation
Calcium currents in bullfrog sympathetic neurons inactivate slowly and partially during depolarizations lasting 0.5-1 s. There is also a slower (minutes) inactivation process with a broad voltage dependence. An irreversible loss of current (rundown) is prominent with low concentrations of intracellular Ca2+ buffers, with either Ca2+ or Ba2+ as the charge carrier. The extent and rate of the more...
متن کاملCalcium currents in bullfrog sympathetic neurons. I. Activation kinetics and pharmacology
The calcium current of bullfrog sympathetic neurons activates and deactivates rapidly (tau less than 3 ms). For brief depolarizations, the current can be fit reasonably well by a Hodgkin-Huxley-type model with a single gating particle of charge +3. With 2 mM Ca2+ as the charge carrier, half-maximal activation occurs at approximately -5 mV, near the voltage where activation and deactivation are ...
متن کاملCalcium Currents in Bullfrog Sympathetic Neurons L Activation Kinetics and Pharmacology
The calcium current o f bullfrog sympathetic neurons activates and deactivates rapidly (7 < 3 ms). For brief depolarizations, the current can be fit reasonably well by a Hodgkin-Huxley-type model with a single gating particle o f charge + 3. With 2 mM Ca 2+ as the charge carrier, half-maximal activation occurs at ~ 5 mV, near the voltage where activation and deactivation are slowest. When extra...
متن کاملSurface charge and calcium channel saturation in bullfrog sympathetic neurons
Currents carried by Ba2+ through calcium channels were recorded in the whole-cell configuration in isolated frog sympathetic neurons. The effect of surface charge on the apparent saturation of the channel with Ba2+ was examined by varying [Ba2+]o and ionic strength. The current increased with [Ba2+]o, and the I-V relation and the activation curve shifted to more positive voltages. The shift of ...
متن کاملIdentification of the single channels that underlie the N-type and L-type calcium currents in bullfrog sympathetic neurons.
Most of the whole-cell calcium current of frog sympathetic neurons is an N-type current, blocked by omega-conotoxin GVIA (omegaCGVIA). Thus, these cells should be an excellent system to study the properties of single N-type channels. However, a channel that is active near -10 mV in isotonic Ba2+, originally identified as "N-type," corresponds more closely to a omegaCGVIA-resistant component of ...
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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1989
ISSN: 0022-1295,1540-7748
DOI: 10.1085/jgp.94.1.169