Activation of Adenosine A₂ Receptors Stimulates Phosphoinositide Metabolism in Rat Peripheral Nerve

Abstract

The effects of adenosine analogues on phosphoinositide metabolism in rat sciatic nerve were examined. Sciatic nerve segments were prelabeled with [

Release inhibitory receptors activation favours the A2A‐adenosine receptor‐mediated facilitation of noradrenaline release in isolated rat tail artery

“…However, A 2A ‐receptors may be promiscuous in their interaction with G proteins and be coupled to transducing mechanisms other than G s (G i/o ; Cunha et al ., 1999; or the G s ‐like protein, G olf ; Kull et al ., 2000). Furthermore, A 2A ‐receptors not only activate adenylate cyclase but also protein kinase C (Gubitz et al ., 1996; Sheldon et al ., 1996), phospholipase C/inositol triphosphate/calmodulin and calmodulin kinase II pathway (Wirkner et al ., 2000), a serine/threonine protein phosphatase (Revan et al ., 1996) or the mitogen‐activated protein kinase cascade (Sexl et al ., 1997). Facing the multiple coupling possibilities of A 2A ‐adenosine receptors we cannot discard the possibility that, in rat tail artery, A 2A ‐receptors may be coupled to transducing systems other than G s and the occurrence of an interaction by a mechanism similar to that proposed for G q/11 coupled receptors (Cox et al ., 2000; see also Selbie & Hill, 1998) cannot be excluded.…”