P2Y1 receptor-mediated glutamate release from cultured dorsal spinal cord astrocytes.
P2 receptors have been implicated in the release of neurotransmitter and proinflammatory cytokines by the response to neuroexcitatory substances in astrocytes. In the present study, we examined the mechanisms of ADP and adenosine 5'-O-2-thiodiphosphate (ADPbetaS, ADP analogue) on glutamate release from cultured dorsal spinal cord astrocytes by using confocal laser scanning microscopy and HPLC. Immunofluorescence activity showed that P2Y(1) receptor protein is expressed in cultured astrocytes. ADP and ADPbetaS-induced [Ca(2+)](i) increase and glutamate release are mediated by P2Y(1) receptor. Ca(2+) release from IP(3)-sensitive calcium stores and protein kinase C (PKC) activation is important for glutamate release from astrocytes. Furthermore, P2Y(1) receptor-evoked glutamate release is regulated by volume-sensitive Cl(-) channels and anion co-transporter, which open up the possibility that P2Y(1) receptor activation causes the increase of cell volume. Release of glutamate by ADPbetaS was abolished by 5-nitro-2 (3-phenyl propy lamino)-benzoate plus furosemide but was unaffected by botulinum toxin A. These observations indicate that P2Y(1) receptor-evoked glutamate may be mediated via volume-sensitive Cl(-) channel but not via exocytosis of glutamate containing vesicles. We speculate that P2Y(1) receptors-evoked glutamate efflux, occurring under pathological condition, may modulate the activity of synapses in spinal cord.
Zeng
Jun-Wei
JW
Department of Neurobiology, Third Military Medical University, Chongqing, China.
Liu
Xiao-Hong
XH
Zhang
Jin-Hai
JH
Wu
Xi-Gui
XG
Ruan
Huai-Zhen
HZ
D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D018118:Chloride Channels / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D018698:Glutamic Acid / Q000378:metabolism*; D018613:Microscopy, Confocal; D020671:Posterior Horn Cells / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000378:metabolism*; D058472:Receptors, Purinergic P2Y1; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013572:Synaptic Vesicles / Q000187:drug effects / Q000378:metabolism; D013873:Thionucleotides / Q000494:pharmacology; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology
D018118:Chloride Channels; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D013873:Thionucleotides; C030812:adenosine 5'-O-(2-thiodiphosphate); D018698:Glutamic Acid; D000244:Adenosine Diphosphate; D011493:Protein Kinase C; D002118:Calcium