title: Purinergic modulation of the excitatory synaptic input onto rat striatal neurons.
abstract: There is no in situ evidence hitherto for a modulation by ATP of the glutamatergic excitatory transmission onto medium spiny neurons (MSNs) in the rat striatum. In order to resolve this question, we used the patch-clamp technique in brain slice preparations to record excitatory postsynaptic currents (EPSCs) evoked by intrastriatal electrical stimulation and applied N-methyl-d-aspartate (NMDA) or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) to activate transmembrane currents of MSNs. In the absence of external Mg(2+), ATP caused a higher maximum inhibition of the EPSCs than adenosine. Only P1 (A(1)), but not P2 receptor antagonists interfered with the effects of both ATP and adenosine. Moreover, A(1) receptor antagonists were less potent in blocking the inhibition by ATP than that by adenosine. Eventually, adenosine deaminase (ADA) almost abolished the adenosine-induced inhibition, but only moderately decreased the ATP-induced inhibition. Antagonists of A(1) receptors (but not of P2 receptors) counteracted the depression by ATP of the current responses to exogenous NMDA, without altering those to AMPA. It is suggested that ATP indirectly, via its degradation product adenosine, stimulates presynaptic inhibitory A(1) receptors situated at glutamatergic nerve terminals of striatal afferents; these nerve terminals are devoid of P2 receptors. However, ATP, in contrast to adenosine, also activates postsynaptic A(1) receptors at the MSN neurons themselves. The resulting negative interaction with NMDA receptors requires localized extracellular catabolism of ATP by ectonucleotidases.
authors.affiliation: Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, D-04107 Leipzig, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Tautenhahn
authors.forename: Anna
authors.initials: A
authors.lastname: Leichsenring
authors.forename: Ilenio
authors.initials: I
authors.lastname: Servettini
authors.forename: Michael
authors.initials: M
authors.lastname: Pesic
authors.forename: Beata
authors.initials: B
authors.lastname: Sperlagh
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Nörenberg
authors.forename: Peter
authors.initials: P
authors.lastname: Illes
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000502:physiology; D004558:Electric Stimulation; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
chemical_list: D018690:Excitatory Amino Acid Agonists; D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D000255:Adenosine Triphosphate; D000241:Adenosine