ATP modulation of synaptic transmission in the spinal substantia gelatinosa.
Actions of adenosine triphosphate (ATP) on neurons of the substantia gelatinosa (SG) were evaluated in spinal cord slices using tight-seal, whole-cell recordings. Bath-applied ATP activated a fast inward current and potentiated both glutamate-induced and synaptically evoked currents by acting through a purinergic receptor with the pharmacology of the P2 type. ATP also induced a delayed slow outward current and depressed synaptic currents that appeared to result from hydrolysis of ATP to adenosine. The inhibitory actions had features suggesting mediation by a P1-like purinergic receptor. Suramin, a putative P2 antagonist, inhibited ATP-induced fast inward currents but did not suppress synaptic currents evoked by dorsal root stimulation. It was concluded that in the SG, ATP released in synaptic regions acts as a synaptic modulator by augmenting excitatory amino acid actions and possibly by also producing a secondary adenosine inhibition.
Li
J
J
Department of Physiology, University of North Carolina at Chapel Hill 27599, USA.
Perl
E R
ER
D000227:Adenine Nucleotides / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D006224:Cricetinae; D004558:Electric Stimulation; D004594:Electrophysiology / Q000379:methods; D005071:Evoked Potentials / Q000187:drug effects; D018698:Glutamic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D008647:Mesocricetus; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D012265:Ribonucleotides / Q000494:pharmacology; D013116:Spinal Cord / Q000502:physiology*; D013376:Substantia Gelatinosa / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects*; D013997:Time Factors
D000227:Adenine Nucleotides; D012265:Ribonucleotides; C022571:adenosine 5'-O-(3-thiotriphosphate); D018698:Glutamic Acid; D000255:Adenosine Triphosphate; D000241:Adenosine