Graefes Arch Clin Exp Ophthalmol
October 2015
Background: The model of the isolated and superfused retina provides the opportunity to test drugs and toxins. Some chemicals have to be applied using low concentrations of organic solvents as carriers. Recently, E-/R-type (Cav2.
View Article and Find Full Text PDFBackground: Calcium channels are essential in coupling action potential to signal transduction in cells. There are several types of calcium channels, which can be pharmacologically classified as L-, N-, P/Q-, R- and T-type. But molecular basis of R-type channels is less clearly understood compared the other channel types.
View Article and Find Full Text PDFPurpose: NiCl(2) (15 microM) enhances the ERG b-wave amplitude of vertebrate retina, up to 1.5-fold by blocking E/R-type voltage-gated Ca(2+) channels, which is mediated by blocking the release of GABA onto ionotropic GABA-A and GABA-C receptors. In vivo, it is likely that zinc, rather than nickel ions, may be involved in the modulation of retinal signalling.
View Article and Find Full Text PDFPurpose: NiCl(2) (15 microM) stimulates the electroretinogram (ERG) b-wave amplitude of vertebrate retina up to 1.5-fold through its blocking of E/R-type voltage-gated Ca(2+) channels. Assuming that such an increase is mediated by blocking the release of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) via ionotropic GABA receptors, we tested the effect of both GABA itself and GABA-receptor antagonists such as (-)bicuculline (1.
View Article and Find Full Text PDFPurpose: In order to record light-evoked responses from photoreceptor cells and the higher neuronal retinal network, the isolated vertebrate retina represents a sensitive tool for basic research of retinal function and for testing the toxicity of ocular therapeutics. In the past, this in vitro technique was optimized for frog and bovine retina; it should be transferred now to the isolated murine retina because the model could allow for functional testing of genes involved in retinal signalling using wild-type and gene-inactivated mice. Thus, alterations in the electroretinogram (ERG) may reveal differences in retinal information processing because of the inactivation of a specific gene.
View Article and Find Full Text PDFMultiple types of voltage-activated Ca2+ channels (T, L, N, P, Q, R type) coexist in excitable cells and participate in synaptic differentiation, secretion, transmitter release, and neuronal plasticity. Ca2+ ions entering cells trigger these events through their interaction with the ion channel itself or through Ca2+ binding to target proteins initiating signalling cascades at cytosolic loops of the ion conducting subunit (Cava1). These loops interact with target proteins in a Ca2+-dependent or independent manner.
View Article and Find Full Text PDFBrain Res Brain Res Protoc
December 2005
The electroretinogram (ERG) of the isolated bovine retina serves as a proven criterion of retinal activity. It is used as a sensitive pharmacological tool for testing effects of applied drugs and toxins on photoreceptors, and higher order neurons that contribute to the generation of the b-wave. Following isolation and detachment from the underlying pigment epithelium, part of the retina was mounted into a closed chamber and perfused by a nutrient solution.
View Article and Find Full Text PDF