The synapses made by many arthropod photoreceptors are disinhibitory and use histamine as their transmitter. Because decreases and not increases in the cleft concentration of transmitter constitute the important event at these synapses, a transporter to clear the cleft of histamine would seem particularly crucial to signal transfer. We report here that 3H-histamine is taken up selectively into ...

PURPOSE Most retinal disease genes are preferentially expressed in photoreceptors, the light-sensitive cells involved in phototransduction. In addition, some of the genes linked to retinal diseases are essential for normal retinal development. The goal of this study was to identify new transcripts enriched in photoreceptors involved in retinal development or diseases. METHODS To isolate uncha...

PURPOSE To investigate the role of glial-cell-line-derived neurotrophic factor (GDNF) on proliferation, differentiation, and apoptosis of different retinal cell types--in particular, photoreceptor cells. METHODS Reaggregated histotypic spheres, derived from retinal cells of the E6 chicken embryo were used. Under rotation, so-called rosetted spheroids arose by aggregation of dissociated retina...

Spontaneous activation of rhodopsin without light absorption occurs at a much lower rate in rod photoreceptors and insect rhabdoms than in cones. The difference lies in the pigment molecules themselves, and has implications for the design of visual photoreceptors.

Abstract—We propose a simple retinomorphic neural network that consists of photoreceptors generating nonuniform outputs for common optical inputs with random offsets, an ensemble of noisy McCulloch-Pitts neurons each of which has random threshold values, local synaptic connections between the photoreceptors and the neurons with variable receptive fields (RFs), output cells, and local synaptic c...

Traditional electrophysiological research on invertebrate photoreceptors has been conducted in vivo, using intracellular recordings from intact compound eyes. The only exception used to be Drosophila melanogaster, which was exhaustively studied by both intracellular recording and patch-clamp methods. Recently, several patch-clamp studies have provided new information on the biophysical properti...

PURPOSE Gene inactivation with homologous recombination in mice is a widely used tool to study gene function. However, many proteins play essential roles in a number of tissues and germline gene inactivation often results in embryonic lethality. To overcome this limitation and to dissect the functions of essential genes beyond embryonic development, we generated mouse rod opsin promoter-control...

Mutations in the extracellular matrix protein eyes shut homolog (EYS) cause photoreceptor degeneration in patients with retinitis pigmentosa 25 (RP25). Functions of EYS remain poorly understood, due in part to the lack of an EYS gene in mouse. We investigated the localization of vertebrate EYS proteins and engineered loss-of-function alleles in zebrafish. Immunostaining indicated that EYS local...

It is shown that light elicits distinct responses from cells in the fly’s eye which are different from photoreceptors. These cells are designated as “slow cells” because of their sluggish response characteristics. Like the visual cells the slow cells depolarize upon light stimulation, but the time course of their responses is clearly different from that of the photoreceptors. Furthermore, the i...