P2X1 and P2X5 subunits form the functional P2X receptor in mouse cortical astrocytes.
ATP plays an important role in signal transduction between neuronal and glial circuits and within glial networks. Here we describe currents activated by ATP in astrocytes acutely isolated from cortical brain slices by non-enzymatic mechanical dissociation. Brain slices were prepared from transgenic mice that express enhanced green fluorescent protein under the control of the human glial fibrillary acidic protein promoter. Astrocytes were studied by whole-cell voltage clamp. Exogenous ATP evoked inward currents in 75 of 81 astrocytes. In the majority ( approximately 65%) of cells, ATP-induced responses comprising a fast and delayed component; in the remaining subpopulation of astrocytes, ATP triggered a smoother response with rapid peak and slowly decaying plateau phase. The fast component of the response was sensitive to low concentrations of ATP (with EC(50) of approximately 40 nm). All ATP-induced currents were blocked by pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS); they were insensitive to ivermectin. Quantitative real-time PCR demonstrated strong expression of P2X(1) and P2X(5) receptor subunits and some expression of P2X(2) subunit mRNAs. The main properties of the ATP-induced response in cortical astrocytes (high sensitivity to ATP, biphasic kinetics, and sensitivity to PPADS) were very similar to those reported for P2X(1/5) heteromeric receptors studied previously in heterologous expression systems.
Lalo
Ulyana
U
Faculty of Life Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom.
Pankratov
Yuri
Y
Wichert
Sven P
SP
Rossner
Moritz J
MJ
North
R Alan
RA
Kirchhoff
Frank
F
Verkhratsky
Alexei
A
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002540:Cerebral Cortex / Q000166:cytology*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D005434:Flow Cytometry / Q000379:methods; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D051379:Mice; D008822:Mice, Transgenic; D018408:Patch-Clamp Techniques / Q000379:methods; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000378:metabolism* / Q000502:physiology*; D058469:Receptors, Purinergic P2X; D058476:Receptors, Purinergic P2X2; D058485:Receptors, Purinergic P2X5
D005904:Glial Fibrillary Acidic Protein; C546401:P2RX2 protein, human; C546465:P2RX5 protein, human; C546402:P2rx2 protein, mouse; C546466:P2rx5 protein, mouse; D010975:Platelet Aggregation Inhibitors; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D058476:Receptors, Purinergic P2X2; D058485:Receptors, Purinergic P2X5; D049452:Green Fluorescent Proteins; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; D011732:Pyridoxal Phosphate; C045674:2',3'-O-(2,4,6-trinitro-cyclohexadienylidine)adenosine 5'-triphosphate; D000255:Adenosine Triphosphate; D002118:Calcium