Quantitative analysis of photoreceptor inputs to external horizontal cells in the goldfish retina.

Abstract

The types of photoreceptors converging onto L-type external horizontal cells (LEHCs) were identified, and their interactions studied, by analyzing responses recorded intracellularly in live, immobilized goldfish under dark-adapted conditions. Our observations indicate that LEHCs receive inputs from red-sensitive and green-sensitive cones, in that : (1) the response waveform differed markedly when elicited by shorter (<550nm)-, as opposed to longer (>600nm)-, wavelength stimuli; (2) on plotting response amplitude vs. log stimulus intensity, the slope of the curves increased as the stimulus wavelengths were decreased, when the amplitude was measured at times >100 msec after the onset of the flash; (3) the spectral sensitivity of LEHC responses, measured at times >100 msec after stimulus onset, was intermediate between those of red-sensitive cones and green-sensitive cones ; and (4) the amplitude of responses to flashes of mixed wavelengths differed from those predicted by the principle of univariance. When brief, red (706 nm) flashes were presented simultaneously with, or within 600 msec after brief, green (502 nm) flashes, the amplitudes of LEHC responses were significantly larger than predicted from linear summation of red and green inputs. Our observations thus indicate not only that red-sensitive and greensensitive cones converge on the LEHC, but in addition, that their inputs interact to enhance LEHC responses. The enhancement might occur, at least in part, presynaptically.

Modulation by melatonin of glutamatergic synaptic transmission in the carp retina

“…Glass microelectrodes filled with 4 m potassium acetate and having a tip resistance of 70–150 MΩ, in combination with an amplifier (MEZ 8300; Nihon Koden Corporation, Tokyo, Japan), were employed to record intracellular potentials. Cone‐ and rod‐driven HCs were identified by reference to previously well‐established criteria (cone HCs: Yang et al 1982, 1983, 1994; Xu et al 2001; rod HCs: Kaneko & Yamada, 1972; Yang et al 1988, 1994).…”

Modulation of cone horizontal cell activity in the teleost fish retina. I. Effects of prolonged darkness and background illumination on light responsiveness

“…The different types of horizontal cells were identified bv nreviouslv established criteria (Werblin and Dowlina. 1969;Kaneko, 1970;Mitarai et al, 1974;Yang~ et al, 1982b;Mange1 et al, 1985). All horizontal cells recorded showed sustained, graded responses with large receptive fields.…”

Functional N-Methyl-<i>D</i>-Aspartate Receptors Are Expressed in Cone-Driven Horizontal Cells in Carp Retina

“…. Test flashes of 500 nm (log I = -0.6) and 680 nm (log I = -0.6) were alternately presented in the dark, which activate short wavelength-sensitive cones, most likely green-sensitive cones, and red-sensitive cones [21] . NMDA of 100 M depolarized the membrane potential from -25 to -15 mV, which was associated with a decrease of the hyperpolarizing light responses (see also fig.…”