Quantal release of ATP in mouse cortex.
Transient currents occur at rest in cortical neurones that reflect the quantal release of transmitters such as glutamate and gamma-aminobutyric acid (GABA). We found a bimodal amplitude distribution for spontaneously occurring inward currents recorded from mouse pyramidal neurones in situ, in acutely isolated brain slices superfused with picrotoxin. Larger events were blocked by glutamate receptor (AMPA, kainate) antagonists; smaller events were partially inhibited by P2X receptor antagonists suramin and PPADS. The decay of the larger events was selectively prolonged by cyclothiazide. Stimulation of single intracortical axons elicited quantal glutamate-mediated currents and also quantal currents with amplitudes corresponding to the smaller spontaneous inward currents. It is likely that the lower amplitude spontaneous events reflect packaged ATP release. This occurs with a lower probability than that of glutamate, and evokes unitary currents about half the amplitude of those mediated through AMPA receptors. Furthermore, the packets of ATP appear to be released from vesicle in a subset of glutamate-containing terminals.
Pankratov
Yuriy
Y
Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
Lalo
Ulyana
U
Verkhratsky
Alexei
A
North
R Alan
RA
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D018756:GABA Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D007608:Kainic Acid / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D058919:Purinergic P2 Receptor Antagonists; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D017470:Receptors, Glutamate / Q000378:metabolism; D013498:Suramin / Q000494:pharmacology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D010975:Platelet Aggregation Inhibitors; D058919:Purinergic P2 Receptor Antagonists; D017470:Receptors, Glutamate; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D011732:Pyridoxal Phosphate; D013498:Suramin; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D000255:Adenosine Triphosphate; D007608:Kainic Acid