Lysophospholipids elevate [Ca2+]i and trigger exocytosis in bovine chromaffin cells
Journal
Neuropharmacology
Journal Volume
51
Journal Issue
1
Pages
18-26
Date Issued
2006
Date
2006
Author(s)
Abstract
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.
Subjects
Ca2+ current; Capacitance; Exocytosis; Intracellular Ca2+ stores; Lysophospholipid
Other Subjects
1 [[6 (3 methoxyestra 1,3,5(10) trien 17beta yl)amino]hexyl] 1h pyrrole 2,5 dione; 2 aminoethoxydiphenylborane; calcium ion; guanine nucleotide binding protein; lysophosphatidic acid; lysophosphatidic acid receptor; lysophospholipid; lysophospholipid receptor; pertussis toxin; ryanodine; sodium ion; sphingosine 1 phosphate; sphingosine 1 phosphate receptor; thapsigargin; calcium; calcium channel blocking agent; catecholamine; drug derivative; enzyme inhibitor; inositol 1,4,5 trisphosphate; lysophosphatidic acid; lysophospholipid; ryanodine; sodium channel blocking agent; sphingosine; sphingosine 1 phosphate; sphingosine 1-phosphate; thapsigargin; animal cell; article; calcium current; chromaffin cell; controlled study; cow; exocytosis; nonhuman; nucleotide sequence; polymerase chain reaction; priority journal; protein expression; sodium current; stimulus secretion coupling; whole cell; animal; biosynthesis; calcium signaling; cattle; cell culture; cell membrane; cell separation; dose response; drug antagonism; drug effect; electrophysiology; metabolism; molecular genetics; physiology; reverse transcription polymerase chain reaction; 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
Type
journal article
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