Electrically evoked calcium responses in rods of the frog retina.

Miyachi, Ei-ichi; Takahashi, Kyoh-Ichi; Murakami, Motohiko

doi:10.2170/jjphysiol.34.307

Cited by 8 publications

(5 citation statements)

References 29 publications

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“…In 20% of cones in turtle retina, feedback from horizontal cells evokes a spike (Piccolino & Gerschenfeld, 1980). Transretinal current pulses also induced oscillatory depolarizations in frog retina (Miyachi et al 1984). In our recordings, the retinal slice was superfused with control Ringer solution and no current injection was applied (Fig.…”

Section: Resultsmentioning

confidence: 99%

Photoreceptor encoding of supersaturating light stimuli in salamander retina

Hou

Slaughter

2005

The Journal of Physiology

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In the dark-adapted salamander retina, spikes could be elicited from rods under normal physiological conditions. Spike activity was observed in rods during the recovery phase of the response to saturating light. These action potentials were calcium spikes, blocked by cadmium and L-type calcium channel blockers. In response to light stimuli that saturate the rod peak response, calcium action potentials occurred with a delay that depended on light intensity, with stronger light increasing spike latency. Therefore, these spikes encode rod visual information at light intensities beyond rod saturation. Postsynaptic currents of similar time course were observed in second and third order neurones. Since rods exposed to brighter light stimuli produced more delayed spike activity, these signals might contribute to negative afterimages.

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Section: Resultsmentioning

confidence: 99%

Photoreceptor encoding of supersaturating light stimuli in salamander retina

Hou

Slaughter

2005

The Journal of Physiology

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“…In addition to contacting cones, horizontal cell dendrites contact the synaptic terminals of rods. Because surround stimulation did not evoke an observable depolarizing response in rods, it was thought for many years that rods did not receive negative feedback from horizontal cells (32,71,254,313). However, as discussed above, the central mechanism for feedback involves a shift in voltage dependence of I Ca that can produce negligible voltage changes in the photoreceptor.…”

Section: Horizontal Cell Feedback To Rodsmentioning

confidence: 99%

Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina

Thoreson

Dacey

2019

Physiological Reviews

121

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Synaptic interactions to extract information about wavelength, and thus color, begin in the vertebrate retina with three classes of light-sensitive cells: rod photoreceptors at low light levels, multiple types of cone photoreceptors that vary in spectral sensitivity, and intrinsically photosensitive ganglion cells that contain the photopigment melanopsin. When isolated from its neighbors, a photoreceptor confounds photon flux with wavelength and so by itself provides no information about color. The retina has evolved elaborate color opponent circuitry for extracting wavelength information by comparing the activities of different photoreceptor types broadly tuned to different parts of the visible spectrum. We review studies concerning the circuit mechanisms mediating opponent interactions in a range of species, from tetrachromatic fish with diverse color opponent cell types to common dichromatic mammals where cone opponency is restricted to a subset of specialized circuits. Distinct among mammals, primates have reinvented trichromatic color vision using novel strategies to incorporate evolution of an additional photopigment gene into the foveal structure and circuitry that supports high-resolution vision. Color vision is absent at scotopic light levels when only rods are active, but rods interact with cone signals to influence color perception at mesopic light levels. Recent evidence suggests melanopsin-mediated signals, which have been identified as a substrate for setting circadian rhythms, may also influence color perception. We consider circuits that may mediate these interactions. While cone opponency is a relatively simple neural computation, it has been implemented in vertebrates by diverse neural mechanisms that are not yet fully understood.

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“…These spikes, apparently arising from a calcium conductance, are further unmasked or facilitated in the presence of strontium, high calcium, or barium Brown & Flaming, 1978). Calcium-dependent spikes have also been observed in frog rods in response to transretinal current pulses (Miyachi et al, 1984). In toad rods, some evidence for depolarizing influences other than spikes has been obtained by modifying the normal superfusing media.…”

Section: Introductionmentioning

confidence: 99%

Prolonged depolarization in rods in situ

Burkhardt

Zhang²,

Gottesman³

1991

Vis Neurosci

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Intracellular recordings were made from rods in the superfused retina of the marine toad (Bufo marinus). It was found that injection of a brief depolarizing current pulse (0.04-1 nA) evoked a distinctive, long-lasting response, here called "the prolonged depolarization." The response appears to be regenerative, has a stereotypical waveform, is typically about 6 mV in amplitude and 3 s in duration, and has a relatively long recovery period (10-60 s). As a rule, the response cannot be directly evoked by light but the current-evoked response is significantly enhanced in the presence of steady illumination. The light-evoked hyperpolarization and the depolarizing spikes of the rod are both attenuated in the presence of the prolonged depolarization. The prolonged depolarization is not an altered manifestation of the depolarizing spikes of toad rods since both can be recorded simultaneously and steady illumination suppresses the spikes while enhancing the prolonged depolarization. The response is enhanced in chloride-free superfusate and also appears to be enhanced by the use of electrodes containing chloride. The response is markedly shortened in superfusates that lack calcium or contain 1-5 mM cobalt. On this and other evidence, it is suggested that the response may be generated by the sequential action of calcium channels and calcium-activated chloride channels. Although rarely evoked by light, the prolonged depolarization of toad rods is otherwise remarkably similar to the prolonged depolarization of turtle cones. It is proposed that the prolonged depolarization, in contrast to the feedback depolarization of cones, arises from mechanisms common to both rods and cones.

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Electrically evoked calcium responses in rods of the frog retina.

Cited by 8 publications

References 29 publications

Photoreceptor encoding of supersaturating light stimuli in salamander retina

Photoreceptor encoding of supersaturating light stimuli in salamander retina

Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina

Prolonged depolarization in rods in situ

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