Depolarizing effect of GABA in horizontal cells of the rabbit retina.
Gamma-amino butyric acid (GABA) has been characterized as an inhibitory neurotransmitter acting through chloride mediated channels in the adult nervous system. Using gramicidin-perforated patch clamp recordings from horizontal cells dissociated from the retinas of adult rabbits, we found that GABA is able to induce cell depolarization. Ionic currents induced by GABA in dissociated horizontal cells showed a reversal potential close to -30 mV. This value is more positive than the resting potential of these cells (ca. -70 mV). Therefore, according to the Nernst equation, the intracellular chloride concentration in horizontal cells was estimated to be of 44 mM. The depolarizing effect of GABA at the dendrites of horizontal cells may serve to shape the center-surround organization of the receptive fields in retinal cells, thereby securing the shape discrimination of visual input.
Varela
Carolina
C
Departamento de Fisiología, Universidad de Alcalá, Alcalá de Henares, E-28871 Madrid, Spain.
Rivera
Luis
L
Blanco
Román
R
De la Villa
Pedro
P
D000818:Animals; D002478:Cells, Cultured; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D015350:Contrast Sensitivity / Q000187:drug effects / Q000502:physiology; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D010364:Pattern Recognition, Visual / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051248:Retinal Horizontal Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*; D014785:Vision, Ocular / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism* / Q000494:pharmacology
D018118:Chloride Channels; D002712:Chlorides; D005680:gamma-Aminobutyric Acid