ryanodine and lysophosphatidic-acid

ryanodine has been researched along with lysophosphatidic-acid* in 2 studies

Other Studies

2 other study(ies) available for ryanodine and lysophosphatidic-acid

ArticleYear
Lysophospholipids elevate [Ca2+]i and trigger exocytosis in bovine chromaffin cells.
    Neuropharmacology, 2006, Volume: 51, Issue:1

    Sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) are responsible for many physiological functions, including angiogenesis, neuronal survival, and immunity. However, little is known about their effects in modulating the stimulus-secretion coupling in bovine chromaffin cells. The result of PCR showed that at least two receptors (S1P(3) and LPA(1)) were expressed in bovine chromaffin cells. The elevation of [Ca(2+)](i) by S1P was fast and sustaining; but the elevation by LPA was slow and transient. The EC(50) for S1P and LPA in elevating the [Ca(2+)](i) were 0.55+/-0.01 and 0.54+/-0.40microM, respectively. This elevation could be totally blocked by thapsigargin, 2-APB, and U73122. Pertussis toxin pretreatment inhibited about half of the elevation in [Ca(2+)](i) suggesting the involvement of G(i) and other G-proteins. Repetitive [Ca(2+)](i) elevations elicited by S1P, but not LPA, were inhibited by ryanodine. S1P was more effective than LPA in triggering exocytosis as measured by the changes in membrane capacitance. The whole-cell Ca(2+) current was inhibited by both lysophospholipids but Na(+) current was inhibited by S1P only. These results suggest the differential effects of LPA and S1P in releasing Ca(2+) from the intracellular Ca(2+) stores and modulating the stimulus-secretion coupling in bovine chromaffin cells.

    Topics: Animals; Base Sequence; Calcium; Calcium Channel Blockers; Calcium Signaling; Catecholamines; Cattle; Cell Membrane; Cell Separation; Cells, Cultured; Chromaffin Cells; Dose-Response Relationship, Drug; Electrophysiology; Enzyme Inhibitors; Exocytosis; Inositol 1,4,5-Trisphosphate; Lysophospholipids; Molecular Sequence Data; Reverse Transcriptase Polymerase Chain Reaction; Ryanodine; Sodium Channel Blockers; Sphingosine; Thapsigargin

2006
Evidence that IP3 and ryanodine-sensitive intra-cellular Ca2+ stores are not involved in acute hyposmotically-induced prolactin release in Tilapia.
    Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology, 2004, Volume: 14, Issue:3

    Prolactin (PRL) cells from the euryhaline tilapia, Oreochromis mossambicus, behave like osmoreceptors by responding directly to reductions in medium osmolality with increased secretion of the osmoregulatory hormone PRL. Extracellular Ca(2+) is essential for the transduction of a hyposmotic stimulus into PRL release. In the current study, the presence and possible role of intracellular Ca(2+) stores during hyposmotic stimulation was investigated using pharmacological approaches. Changes in intracellular Ca(2+) concentration were measured with fura-2 in isolated PRL cells. Intracellular Ca(2+) stores were depleted in dispersed PRL cells with thapsigargin (1 microM) or cyclopiazonic acid (CPA, 10 microM). Pre-incubation with thapsigargin prevented the rise in [Ca(2+)](i) induced by lysophosphatidic acid (LPA, 1 microM), an activator of the IP(3) signalling cascade, but did not prevent the hyposmotically-induced rise in [Ca(2+)](i) in medium with normal [Ca(2+)] (2mM). Pre-treatment with CPA produced similar results. Prolactin release from dispersed cells followed a pattern that paralleled observed changes in [Ca(2+)](i). CPA inhibited LPA-induced prolactin release but not hyposmotically-induced release. Xestospongin C (1microM), an inhibitor of IP(3) receptors, had no effect on hyposmotically-induced PRL release. Pre-exposure to caffeine (10mM) or ryanodine (1microM) did not prevent a hyposmotically-induced rise in [Ca(2+)](i). Taken together these results indicate the presence of IP(3) and ryanodine-sensitive Ca(2+) stores in tilapia PRL cells. However, the rapid rise in intracellular [Ca(2+)] needed for acute PRL release in response to hyposmotic medium can occur independently of these intracellular Ca(2+) stores.

    Topics: Animals; Calcium; Cells, Cultured; Enzyme Inhibitors; Inositol Phosphates; Lysophospholipids; Osmosis; Osmotic Pressure; Pituitary Gland; Prolactin; Ryanodine; Signal Transduction; Tilapia

2004