Elsevier

Neuroscience Letters

Volume 289, Issue 2, 4 August 2000, Pages 127-130
Neuroscience Letters

Adenosine A2A receptor facilitation of synaptic transmission in the CA1 area of the rat hippocampus requires protein kinase C but not protein kinase A activation

https://doi.org/10.1016/S0304-3940(00)01295-7Get rights and content

Abstract

Adenosine is a neuromodulator in the hippocampus acting mainly via inhibitory A1 receptors but also via facilitatory A2A receptors. We now investigated the transducing system operated by hippocampal A2A receptors. The selective A2A receptor agonist, CGS 21680 (10 nM), facilitated synaptic transmission by 14%, an effect not modified by the phosphodiesterase IV inhibitor, rolipram (30 μM), or by the adenylate cyclase activator, forskolin (3 μM), or by the protein kinase A inhibitor, HA-1004 (10 μM), but nearly abolished by the protein kinase C inhibitors, chelerythrine (6 μM) or bisindolylmaleimide I (1 μM). Inhibition of protein kinase C also prevented the A2A receptor-induced attenuation of A1 receptor-mediated inhibition of hippocampal synaptic transmission. These results indicate that adenosine A2A receptor facilitation of hippocampal synaptic transmission involves protein kinase C rather than protein kinase A activation.

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Acknowledgements

We thank Schering AG for the gift of rolipram, Professor C.B. Duarte for lending bisindolylmaleimide I and Professor Silva Carvalho (Department Physiol, Fac. Medicine Lisbon) for animal house facilities. RAC is indebt to L.V. Lopes for carrying some of the experiments on A2A/A1 receptor interaction. Supported by Fundação para a Ciência e Tecnologia.

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