Adenosine A3 receptors are located in neurons of the rat hippocampus

Adenosine is a neuromodulator acting mainly via inhibitory A, and facilitatory A(2A) receptors. Whole tissue PCR also identified adenosine A(3) receptors in the brain and A(3) receptor agonists affect CNS neuronal responses and viability. However, recent reports failed to detect A(3) receptor expression in CNS neurons and showed that A(3) receptor agonists can bind and activate A(1) receptors. We now present evidence for the presence of A(3) receptor mRNA in CNS neurons using single cell PCR analysis of laser dissected hippocampal neurons. Western blot analysis showed that A(3) receptors are present in rat hippocampal nerve terminal membranes. This indicates that A(3) receptors are present in CNS neurons in the hippocampus.