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Co-localization and functional cross-talk between A1 and P2Y1 purine receptors in rat hippocampus
Article first published online: 2 AUG 2007
European Journal of Neuroscience
Volume 26, Issue 4, pages 890–902, August 2007
How to Cite
Tonazzini, I., Trincavelli, M. L., Storm-Mathisen, J., Martini, C. and Bergersen, L. H. (2007), Co-localization and functional cross-talk between A1 and P2Y1 purine receptors in rat hippocampus. European Journal of Neuroscience, 26: 890–902. doi: 10.1111/j.1460-9568.2007.05697.x
- Issue published online: 2 AUG 2007
- Article first published online: 2 AUG 2007
- Received 13 February 2007, revised 30 May 2007, accepted 11 June 2007
- brain damage;
- electron microscopy;
- G protein coupled receptors;
Adenosine and ATP, via their specific P1 and P2 receptors, modulate a wide variety of cellular and tissue functions, playing a neuroprotective or neurodegenerative role in brain damage conditions. Although, in general, adenosine inhibits excitability and ATP functions as an excitatory transmitter in the central nervous system, recent data suggest the existence of a heterodimerization and a functional interaction between P1 and P2 receptors in the brain. In particular, interactions of adenosine A1 and P2Y1 receptors may play important roles in the purinergic signalling cascade. In the present work, we investigated the subcellular localization/co-localization of the receptors and their functional cross-talk at the membrane level in Wistar rat hippocampus. This is a particularly vulnerable brain area, which is sensitive to adenosine- and ATP-mediated control of glutamatergic transmission. The postembedding immunogold electron microscopy technique showed that the two receptors are co-localized at the synaptic membranes and surrounding astroglial membranes of glutamatergic synapses. To investigate the functional cross-talk between the two types of purinergic receptors, we evaluated the reciprocal effects of their activation on their G protein coupling. P2Y1 receptor stimulation impaired the potency of A1 receptor coupling to G protein, whereas the stimulation of A1 receptors increased the functional responsiveness of P2Y1 receptors. The results demonstrated an A1–P2Y1 receptor co-localization at glutamatergic synapses and surrounding astrocytes and a functional interaction between these receptors in hippocampus, suggesting ATP and adenosine can interact in purine-mediated signalling. This may be particularly important during pathological conditions, when large amounts of these mediators are released.