Modulation of the Gaba- and Pentobarbital-Gated Cl Current by Intracellular Calcium in Frog Sensory Neurons
Voltage-dependent Ca2+ currents are well known to play an important role in the regulation of a vast number of neuronal functions. The transient increase in intracellular free calcium resulting from Ca2+-channel activation has been shown to trigger various ionic currents in the soma of a variety of nerve cells, i.e., calcium-dependent potassium, chloride, or unselective anion conductances. In addition to this well-established interaction with ionic channels, Ca2+ has been demonstrated to modulate desensitization kinetics of ACh receptors in the neuromuscular end plate (Miledi, 1980) and to inhibit a nicotinic chloride response in Aplysia neurons (Chemeris et al., 1982) as well as the nicotinic cation response in frog sympathetic ganglion cells (Morita et al., 1979). These findings point to a possible involvement of Ca2+ ions not only in the regulation of pure ionic channels but also in the modulation of transmitter-operated receptor—ionophore complexes.
KeywordsDepression Trypsin HEPES Acetylcholine Collagenase
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