title: Long-term depression is not modulated by ATP receptors in the rat CA1 hippocampal region.
abstract: ATP is an important extracellular messenger in the CNS. In the hippocampus, a brain structure relevant for learning and memory processes, it acts both as a modulator and as a mediator of synaptic transmission, with implications for synaptic plasticity phenomena. Recent evidence suggests that ATP modulates activity-dependent long-term potentiation (LTP) of Schaffer collateral-CA1 synapses. However, it remains unclear if ATP also modulates LTP counterpart's phenomenon, long-term depression (LTD), in the rat hippocampus. This study investigated the effect of ATP analogues on homosynaptic LTD, induced by low-frequency stimulation of the Schaffer collaterals (1 Hz; 900 pulses) in the CA1 region of young rat hippocampal slices. The metabolically stable ATP analogues beta,gamma-ImATP (20 microM), a P2 receptor agonist, and alpha,beta-MeATP (20 microM), a preferential P2X(1,3) receptor agonist, did not modify LTD (LTD values of 14.7+/-0.5% and 14.1+/-3% for aCSF controls and of 15.1+/-4% and 19.0+/-5.2% for beta,gamma-ImATP and alpha,beta-MeATP, respectively). The ATP analogue beta,gamma-ImATP (20 microM) did not modify LTD also in the presence of the adenosine A1 receptor antagonist DPCPX (50 nM) (21.5+/-4.2% for DPCPX only and of 23.8+/-8.9% for DPCPX plus beta,gamma-ImATP). Finally, the preferential P2X(1,3) receptor antagonist NF023 (10 microM) had also no effect on LTD (18.6+/-5.2% for aCSF and of 18.7+/-5.2% for NF023). The present results suggest that ATP does not modulate activity-dependent homosynaptic LTD in the rat CA1 hippocampal region by activating P2 receptors.
authors.affiliation: Laboratory of Neurosciences, Institute of Molecular Medicine and Faculty of Medicine of Lisbon, Lisbon, Portugal. bruno.da.silva@ed.ac.uk
authors.forename: Bruno M
authors.initials: BM
authors.lastname: da Silva
authors.forename: Alexandre
authors.initials: A
authors.lastname: de Mendonça
authors.forename: Joaquim A
authors.initials: JA
authors.lastname: Ribeiro
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D066298:In Vitro Techniques; D036881:Long-Term Synaptic Depression / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D008297:Male; D018408:Patch-Clamp Techniques / Q000379:methods; D058910:Purinergic P2 Receptor Agonists; D058919:Purinergic P2 Receptor Antagonists; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D013997:Time Factors; D014970:Xanthines / Q000494:pharmacology
chemical_list: D058910:Purinergic P2 Receptor Agonists; D058919:Purinergic P2 Receptor Antagonists; D018048:Receptors, Purinergic P2; D014970:Xanthines; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; C005147:5'-adenylyl (beta,gamma-methylene)diphosphonate; D011732:Pyridoxal Phosphate; D000255:Adenosine Triphosphate; C051360:1,3-dipropyl-8-cyclopentylxanthine; C002630:alpha,beta-methyleneadenosine 5'-triphosphate