Investigation of the nature of electrical responses of horizontal cells of the fish retina

Trifonov, Yu. A.; Chailakhyan, L. M.; Byzov, A. L.

doi:10.1007/bf01065594

Cited by 13 publications

(10 citation statements)

References 11 publications

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“…3). Therefore, the values of reversal potentials measured in this experiment are believed to be much more reliable than those obtained by conventional methods (Trifonov et al 1970;Marshall & Werblin, 1978). The reversal potentials of the light responses, the e.p.s.p.s and the amino acid potentials were estimated at a very narrow range (-5 to -10 mV), or rather at the same potential level if experimental errors are taken into account (Figs. 4, 5 and 7).…”

Section: Discussionmentioning

confidence: 99%

“…and Glu or Asp potential, must coincide at the same potential level. However, accurate measurement ofthe reversal potentials was difficult, because adjacent horizontal cells are electrically coupled through gap junctions (Yamada & Ishikawa, 1965;Witkovsky & Dowling, 1969;Kaneko, 1971;Simon, 1973;Fain, Gold & Dowling, 1976), and the syncytial horizontal cell complex called the S-space (Naka & Rushton, 1967) cannot be uniformly polarized by current injection (Trifonov, Chailakhyan & Byzov, 1970;Marshall & Werblin, 1978).…”

Section: Introductionmentioning

confidence: 99%

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Calcium action potential and its use for measurement of reversal potentials of horizontal cell responses in carp retina.

Murakami

Takahashi

1987

The Journal of Physiology

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1. In the carp retina perfused with a solution containing high‐Ca2+, Ba2+ and some K+‐channel blockers, the horizontal cell produced a regenerative Ca2+ action potential when the cell was depolarized by bath application of L‐glutamate (Glu) or L‐aspartate (Asp). The action potential was triggered also by a transretinal electrical stimulation which evoked an e.p.s.p. in the horizontal cell. In this solution, some cells produced the action potential spontaneously. 2. The action potential had an overshoot of about 20 mV which lasted for several seconds or even minutes. It had a threshold and showed refractoriness. In addition, it was insensitive to tetrodotoxin, but was blocked by Co2+. These observations revealed, in horizontal cells in situ, the presence of a voltage‐dependent Ca2+ channel similar to that found in dissociated cells. It is supposed that, in a physiological environment, the Ca2+ channel is prevented from becoming regenerative probably because it is counteracted by K+ channel activities. 3. Simultaneous recordings from two separate horizontal cells showed full synchronization of the Ca2+ action potentials whose amplitudes were identical. The potential uniformity thus formed in the S‐space (Naka & Rushton, 1967) enabled us to measure reversal potentials of horizontal cell responses irrespective of the electrical coupling between the cells. 4. During an overshoot of the Ca2+ action potential, an electrically evoked e.p.s.p. as well as a light response appeared with polarities reversed to those elicited at the resting state. Their reversal potentials could be estimated within a very narrow range between ‐5 and ‐10 mV. At this range, both Glu‐ and Asp‐induced potentials reversed the polarity, too. 5. These observations suggest that the ionic mechanisms are identical in the three kinds of horizontal cell response: light response, e.p.s.p. and amino acid‐induced potentials.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calcium action potential and its use for measurement of reversal potentials of horizontal cell responses in carp retina.

Murakami

Takahashi

1987

The Journal of Physiology

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“…The concentration required to record measurable effect, or the highest concentration tried when no effect was seen, is shown in parentheses. Under the retinal condition tested, the substance caused a depolarization (+, [1][2][3][4][5] is actively taken up into glial cells in the retina; and the retinal uptake of aspartate is saturable, with high-and low-affinity components (21). We have noted above that the effect of 1-5 mM glutamate on the horizontal cells appears to be a nonspecific or nonsynaptic effect.…”

mentioning

confidence: 87%

“…This depolarization appears to result in a continuous release of neurotransmitter from the receptor onto second-order neurons (2). Light, by supressing the sodium current, hyperpolarizes the photoreceptor and depresses the release of transmitter (3,4).…”

mentioning

confidence: 99%

L-aspartate: evidence for a role in cone photoreceptor synaptic transmission in the carp retina.

Wu¹,

Dowling²

1978

Proc. Natl. Acad. Sci. U.S.A.

123

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A number of putative neurotransmitter substances and their antagonists were applied to the carp retina while intracellular recordings from L-type cone horizontal cells were made. Of all the substances tested, L-aspartate was found to be the most potent agent in depolarizing these horizontal cells in dark-adapted, partially light-adapted, and Co2+-treated retinas. Furthermore, DL-a-aminoadipate, an L-aspartate antagonist, blocked the effects of both the endogenous photoreceptor transmitter and exogenously applied L-aspartate on the horizontal cells. The results suggest that L-aspartate and the natural transmitter interact with the same population of postsynaptic receptors in the horizontal cell membrane.In darkness, the vertebrate photoreceptor is partially depolarized by a sodium current that flows into the outer segment of the cell (1). This depolarization appears to result in a continuous release of neurotransmitter from the receptor onto second-order neurons (2). Light, by supressing the sodium current, hyperpolarizes the photoreceptor and depresses the release of transmitter (3, 4). The light response of second-order neurons (the horizontal and bipolar cells) is thus caused by a decrease of neurotransmitter secretion from the receptor terminal.Horizontal cells and one subclass of bipolar cell [the hyperpolarizing bipolar cell (HBC)] hyperpolarize in response to light; another subclass of bipolar cell [the depolarizing bipolar cell (DBC)] depolarizes in light. It is reasonable to assume, therefore, that, if the photoreceptor transmitter acts directly on these elements, it will depolarize horizontal cells and the HBC and hyperpolarize the DBC. Blockade of transmitter release from the receptor terminals, on the other hand, should mimic the effects of light on these cell types (5-7).

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“…They are also close to the reversal potentials ofresponses ofretinal horizontal cells in situ to both photoreceptor input and to L-glutamate (Trifonov, Chailahian & Byzov, 1971;Marshall & Werblin, 1978;Shiells et al 1981). In addition, the present results indicate that L-glutamate may increase the conductance ofsolitary horizontal cells either to an ion whose equilibrium (Nernst) potential is between 0 and -20 mV, or else both to ions whose equilibrium potential are positive (viz.…”

Section: Reversal Potential Of Solitary Horizontal-cell Responses To mentioning

confidence: 99%

Responses of solitary retinal horizontal cells from Carassius auratus to L‐glutamate and related amino acids.

Ishida

Kaneko

Tachibana

1984

The Journal of Physiology

122

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SUMMARY1. Effects of L-glutamate and its analogues on membrane potentials of solitary horizontal cells were studied by intracellular recording. L-glutamate depolarized these cells at micromolar concentrations (> 10,sM), while D-glutamate and L-a-amino adipic acid produced slight depolarizations only at millimolar concentrations. Neither L-nor D-aspartate, even at millimolar doses, produced any change in solitary horizontal-cell resting potential.2. Solitary horizontal-cell responses to L-glutamate did not desensitize detectably. Responses to pairs of brief, ionophoretic pulses of L-glutamate were nearly equal in amplitude at inter-pulse intervals as short as 50 ms. Responses to maintained applications of low doses of L-glutamate did not decline for as long as 2 min.3. Depolarizing responses were produced by ionophoretic applications of Lglutamate near cell somata as well as dendrites. The mean sensitivity was 1t4 + 1-5 mV/nC with a maximum of 5-1 mV/nC. 4. Depolarizing responses to L-glutamate reversed in polarity at membrane potentials between 0 and -20 mV, were accompanied by a decrease in membrane slope resistance, and were suppressed by replacement of extracellular sodium ions with choline.5. These results demonstrate that chemosensitivity of retinal horizontal cells to acidic amino acids persists after dissociation protocols, and in several respects resembles that found in horizontal cells in situ. These findings are consistent with the notion that retinal horizontal cells receive a synaptic input involving L-glutamate or a similar substance.

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Investigation of the nature of electrical responses of horizontal cells of the fish retina

Cited by 13 publications

References 11 publications

Calcium action potential and its use for measurement of reversal potentials of horizontal cell responses in carp retina.

Calcium action potential and its use for measurement of reversal potentials of horizontal cell responses in carp retina.

L-aspartate: evidence for a role in cone photoreceptor synaptic transmission in the carp retina.

Responses of solitary retinal horizontal cells from Carassius auratus to L‐glutamate and related amino acids.

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