Receptive field properties of starburst cholinergic amacrine cells in the rabbit retina.
Patch-clamp recordings were made from ON starburst cholinergic amacrine cells with somas located in the ganglion cell layer of an isolated, dark-adapted rabbit retina preparation. Light responses were analysed and cell identify was confirmed anatomically. The centre light response had a linear current-voltage relation with a reversal potential close to 0 mV. The receptive field size was similar to the dendritic field size. Cholinergic amacrine cells displayed significant surround inhibition. The receptive field profile consisted of a central excitatory region flanked by an inhibitory surround. The surround attenuated the central response to 36% of the maximum. The surround was probably mediated by a combination of presynaptic and postsynaptic inhibition. Starburst amacrine cells did not display action potentials and the presence of a large, voltage-dependent outward current limited depolarizing responses to a maximum potential of about -40 mV. Light responses were completely suppressed during application of 100 microM D,L-2-amino-4-phosphonobutyric acid (APB), consistent with activation exclusively through rod bipolar cells (on) and ON-cone bipolar cells. In darkness the cells displayed a tonic inward current that could be blocked by 100 microM APB and 2 microM CNQX.
Taylor
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WR
Neuroanatomische Abteilung, Max-Planck-Institut für Hirnforschung, Frankfurt, Germany.
Wässle
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D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D002799:Cholinergic Fibers / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D011817:Rabbits; D012160:Retina / Q000502:physiology*; D013997:Time Factors
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione