The modulation of excitatory synaptic transmission by adenosine in area CA1 of the rat hippocampus is temperature dependent.
We tested the possibility that extracellular adenosine concentration varies with tissue temperature by measuring the tonic adenosinergic inhibition of excitatory synaptic transmission at different temperatures in the in vitro rat hippocampus. Application of the A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) enhanced population excitatory postsynaptic potentials (EPSPs) by antagonizing tonic adenosinergic inhibition; this effect was greatest at 25 degrees C, and was progressively reduced at 35 and 37.5 degrees C. These results demonstrate that tonic adenosinergic inhibition is inversely related to temperature. In a second experiment, an exogenous A1 agonist, N6-cyclohexyladenosine (CHA), was applied to slices to inhibit evoked EPSPs. CHA inhibition of EPSPs was greater at 35 than at 25 degrees C, demonstrating that the reduced adenosinergic inhibition at higher temperatures is not a result of reduced A1 receptor function.
Grover
L M
LM
Department of Physiology, Marshall University School of Medicine, Huntington, WV 25755-9340, USA. grover@marshall.edu
Yan
C
C
D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D051381:Rats; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013696:Temperature; D014970:Xanthines / Q000494:pharmacology*
D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D014970:Xanthines; C027513:N(6)-cyclohexyladenosine; C051360:1,3-dipropyl-8-cyclopentylxanthine; D000241:Adenosine