horizontal cell

(redirected from Horizontal cells)
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horizontal cell

A neuron of the inner nuclear layer of the retina. The axons of these cells run horizontally and connect various parts of the retina.
See also: cell
References in periodicals archive ?
Although the possibility remains that zinc exerts a direct effect on calcium channels, its effect on transmitter release may derive from its ability to modulate the hemichannel currents on horizontal cells at the photoreceptor synapse.
Focusing their efforts on the melanopsin light sensor, which is responsible for sensing day and night but barely involved - in mammals, at least - in seeing images, Yau's team looked for melanopsin-containing cells in other vertebrates, and found some in the retinal horizontal cells in goldfish and catfish.
A recent hypothesis based on evidence from carp retina holds that currents through Cx26 hemichannels on horizontal cell dendritic processes serve to modulate calcium currents and related photoreceptor transmitter release via an ephaptic current within the synaptic region.
It would also be consistent with a reduced inhibition of glutamate receptors on second-order retinal neurons (5), or possibly even an action of zinc on hemichannels (15), since hemichannels have been suggested as a means of feedback from horizontal cells onto cones in the carp retina, where the hemichannel blocker cambenoxolone has been shown to alter feedback-mediated responses (16).
In the experiments reported here, we sought to develop methods to locally raise intracellular calcium levels in horizontal cells.
All-trans retinoic acid (RA), a metabolite of vitamin A, acting through a plasma membrane retinoic acid-binding protein, has been shown to reduce electrical coupling between horizontal cells both in situ and between cell pairs in culture (10).
1B) were obtained from horizontal cells like the one shown in the fluorescence micrograph of Figure 1C.
Retinal horizontal cells are second order neurons that receive direct input from photoreceptors.
Positive controls to ensure that the imaging system was working properly included demonstrations: (a) that increases in calcium were observed in skate Muller and horizontal cells upon application of the calcium ionophore ionomycin [ILLUSTRATION FOR FIGURE 1C OMITTED]; and (b) that glutamate and GABA both increased calcium levels in isolated skate retinal horizontal cells [ILLUSTRATION FOR FIGURE 1D OMITTED], as had been described previously (14).
Figure 1 shows that a robust and easily detectable signal could indeed be detected from isolated external horizontal cells using these techniques.
Horizontal cells of the vertebrate retina are interneurons; they form a lateral inhibitory pathway in the visual system mediating interactions between photoreceptors and bipolar cells at the first stage of signal transduction.
The purpose of the present study was to determine whether such self-referencing, ion-selective electrodes could be used to detect steady ion fluxes from retinal horizontal cells of the skate.

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