BACKGROUND: Voltage-dependent Ca(2+) channels trigger and control important cellular processes like neurotransmitter release and secretion, long-term potentiation, and gene expression in excitable cells. During retinal signal perception and processing, presynaptic Ca(2+) channels facilitate neurotransmitter release in photoreceptors and bipolar neurons, at nonspiking synapses which generate graded potentials. METHODS: The nature of voltage-gated Ca(2+) channels involved in retinal signal transduction is investigated in the present report by recording the electroretinogram (ERG) from the isolated and perfused bovine retina. Transcripts of the E/R- and T-type Ca(2+) channels are detected by RT-PCR. RESULTS: Using the Ca(2+) channel antagonists (+/-)-isradipine, NiCl(2), mibefradil, and SNX-482 results in either stimulatory or inhibitory effects on the ERG b-wave amplitude. On the transcript level, mRNA is detected for the E/R-type and a T-type voltage-gated Ca(2+) channel containing Ca(v)2.3 and Ca(v)3.1 as ion-conducting subunits, respectively. CONCLUSION: Blocking of the E/R-type Ca(2+) channels by NiCl(2) (10 microM) and SNX-482 (30 nM) contributes to the stimulatory effect, whereas antagonism of T-type as well as L-type Ca(2+) channels meditates the inhibitory action on the b-wave amplitude. Thus, a novel function for E/R-type voltage-gated Ca(2+) channels is probably associated with the visual signal transduction in the mammalian retina.
BACKGROUND: Voltage-dependent Ca(2+) channels trigger and control important cellular processes like neurotransmitter release and secretion, long-term potentiation, and gene expression in excitable cells. During retinal signal perception and processing, presynaptic Ca(2+) channels facilitate neurotransmitter release in photoreceptors and bipolar neurons, at nonspiking synapses which generate graded potentials. METHODS: The nature of voltage-gated Ca(2+) channels involved in retinal signal transduction is investigated in the present report by recording the electroretinogram (ERG) from the isolated and perfused bovine retina. Transcripts of the E/R- and T-type Ca(2+) channels are detected by RT-PCR. RESULTS: Using the Ca(2+) channel antagonists (+/-)-isradipine, NiCl(2), mibefradil, and SNX-482 results in either stimulatory or inhibitory effects on the ERG b-wave amplitude. On the transcript level, mRNA is detected for the E/R-type and a T-type voltage-gated Ca(2+) channel containing Ca(v)2.3 and Ca(v)3.1 as ion-conducting subunits, respectively. CONCLUSION: Blocking of the E/R-type Ca(2+) channels by NiCl(2) (10 microM) and SNX-482 (30 nM) contributes to the stimulatory effect, whereas antagonism of T-type as well as L-type Ca(2+) channels meditates the inhibitory action on the b-wave amplitude. Thus, a novel function for E/R-type voltage-gated Ca(2+) channels is probably associated with the visual signal transduction in the mammalian retina.
Authors: Kai Januschowski; Sebastian Mueller; Rebecca Dollinger; Sven Schnichels; Johanna Hofmann; Martin S Spitzer; Karl-Ulrich Bartz-Schmidt; Peter Szurman; Sebastian Thaler Journal: Graefes Arch Clin Exp Ophthalmol Date: 2014-05-02 Impact factor: 3.117
Authors: Jan Niklas Lüke; Felix Neumaier; Serdar Alpdogan; Jürgen Hescheler; Toni Schneider; Walid Albanna; Isha Akhtar-Schäfer Journal: BMC Ophthalmol Date: 2020-05-06 Impact factor: 2.209