Mechanisms of chloride transport in crayfish stretch receptor neurones and guinea pig vas deferens: implications for inhibition mediated by GABA.
Since activation of GABAA receptors is believed to open an associated Cl- channel, the intracellular Cl- activity (aiCl) must be lower than that predicted from a passive distribution, to account for hyperpolarizing responses, or higher, to account for depolarizing responses. The physiological and pharmacological properties of the implied Cl- extruding and accumulating mechanisms have been investigated by direct measurements of aiCl. A coupled K+-Cl- co-transport has been found in crayfish stretch receptor neurones and a predominating Cl(-)HCO3(-) exchange in guinea pig vas deferens. From the different ionic mechanisms involved in Cl- extrusion and accumulation, it is proposed that drugs which affect Cl- transport mechanisms will reduce GABA responses of both polarities only if their action is via interference with the Cl- recognition site, but not if it is via interference with the co- or counter-ion recognition site.
D000641:Ammonia / Q000378:metabolism; D000818:Animals; D003400:Astacoidea; D001639:Bicarbonates / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000378:metabolism*; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology*; D008564:Membrane Potentials; D009130:Muscle, Smooth / Q000294:innervation*; D009433:Neural Inhibition; D011188:Potassium / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000502:physiology; D011963:Receptors, GABA-A; D012964:Sodium / Q000378:metabolism; D014649:Vas Deferens / Q000294:innervation; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D001639:Bicarbonates; D002712:Chlorides; D007473:Ion Channels; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D000641:Ammonia; D012964:Sodium; D011188:Potassium