Different actions of intracellular free calcium on resting and GABA-gated chloride conductances.
The effects of voltage-dependent Ca2+ current (ICa) on resting and gamma-aminobutyric acid (GABA)-gated Cl- conductances were studied in isolated frog sensory neurons. The amplitude of GABA-gated Cl- current (ICl) was greatly suppressed by a preceding ICa. The GABA dose-response curve was shifted to the right without changing the maximum response by increasing [Ca2+]i. An ICa-activated ICl was observed as an inward tail current on the 'off' phase of ICa. This tail current was easily saturated by increasing the amount of Ca2+ influx.
D000818:Animals; D001001:Anura; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002712:Chlorides / Q000378:metabolism*; D004553:Electric Conductivity; D007425:Intracellular Membranes / Q000378:metabolism; D007473:Ion Channels / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D002712:Chlorides; D007473:Ion Channels; D005680:gamma-Aminobutyric Acid; D002118:Calcium