Evidence for a cGMP gated cation channel in photoreceptor cell membranes of Sepia officinalis.
It is assumed that cyclic nucleotides are involved in signal transduction of invertebrate photoreceptors. In this study, membranes of photoreceptor cells from freshly caught cuttlefish were isolated, and the membrane proteins were reconstituted into proteoliposomes. With the dye Neutral red it was possible to measure cyclic nucleotide induced Na+ fluxes into the liposomes. cGMP and cAMP concentrations for half maximal activation of Na+ fluxes are 77 microM and 224 microM, respectively, with Hill coefficients of 2.0 for cGMP and 2.4 for cAMP. These fluxes may demonstrate the presence of at least one cyclic nucleotide gated cation channel in the membranes of the photoreceptor cells of the invertebrate Sepia officinalis.
Huppertz
B
B
Institut für Biologie II, RWTH Aachen, Germany.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism*; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D007473:Ion Channels / Q000378:metabolism*; D008854:Microscopy, Electron; D008974:Mollusca / Q000378:metabolism* / Q000648:ultrastructure; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism* / Q000648:ultrastructure; D011510:Proteolipids; D015398:Signal Transduction
D007473:Ion Channels; D011510:Proteolipids; C020485:proteoliposomes; D006152:Cyclic GMP