Extracellular adenosine 5′-triphosphate plus activation of glutamatergic receptors induces long-term potentiation in CA1 neurons of guinea pig hippocampal slices

The mechanism of adenosine 5'-triphosphate (ATP)-induced long-term potentiation (LTP) was studied pharmacologically using guinea pig hippocampal slices. Application of 10 mu M ATP for 10 min transiently depressed, then slowly augmented, synaptic transmission in CA1 neurons, leading to LTP. This ATP-induced LTP was blocked by addition of an N-methyl-D-aspartate (NMDA) glutamate receptor antagonist. Furthermore, co-application of 10 mu M ATP and 100 mu M L-glutamate for 10 min also induced LTP, and this effect was blocked by the use of Ca2+-free solution during drug application. These results suggest that, in CA1 neurons, a co-operative effect involving extracellular ATP and the activation of NMDA receptors, which increases intracellular Ca2+ levels, is required to trigger the intracellular biological process involved in ATP-induced LTP. (C) 1999 Elsevier Science ireland Ltd. All rights reserved.