ATP-activated cationic and anionic conductances in cultured rat hippocampal neurons.
The effects of adenosine 5'-triphosphate (ATP) on voltage-clamped and dissociated rat hippocampal neurons was investigated. Over 30% of neurons possessed ATP-activated inward currents at a holding potential of -70 mV. The ED50 for these currents was 150 mu M. At this concentration they were blocked by suramin (1 mM), indicating the involvement of P2-purinoceptors. The P2 purinoceptor agonist potency was 2-methylthio ATP > ATP > ADP > alpha,beta-methylene ATP, thus identifying these purinoceptors as belonging to the P2x subclass. The reversal potential for the ATP-activated currents was -45 +/- 8 mV. Ion substitution experiments showed that the permeability ratio for K+/Na+/Cs+/Cl-, was 18:3:2:1, according to the Goldman-Hodgkin-Katz equation, so that ATP activates cationic and anionic conductances in hippocampal neurons.
Balachandran
C
C
The Neurobiology Laboratory, Department of Physiology, University of Sydney, Australia.
Bennett
M R
MR
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000502:physiology*; D000818:Animals; D002478:Cells, Cultured; D004594:Electrophysiology; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D007473:Ion Channels / Q000378:metabolism* / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000187:drug effects; D013498:Suramin / Q000494:pharmacology
D007473:Ion Channels; D018048:Receptors, Purinergic P2; D013498:Suramin; D000255:Adenosine Triphosphate