Abstract
ATP and glutamate are the principal gliotransmitters released from astrocytes through various mechanisms. Glutamate released from astrocytes activates neuronal receptors including NMDA receptors (Araque et al., 1998) and facilitates glutamate release (Perea & Araque, 2007). In contrast, ATP of astrocytic origin is rapidly hydrolysed into adenosine in the brain slices that are rich in ecto-nucleuotidase and activates presynaptic A1 receptors, which in turn attenuates excitatory transmission (Zhang et al, 2003; Pascual et al., 2005; Serrano et al., 2006). In the nucleus of the solitary tract, activation of presynaptic P2X receptors, extracellular ATP-gated cation channels, facilitates glutamate release (Kato & Shigetomi, 2001; Shigatomi & Kato, 2004). Here I present lines of structural, pharmacological, and circumstantial evidence supporting that these presynaptic P2X receptors are the "interface" molecules directly transducing excitation of "syncytia network" of astrocytes into synaptic excitation of neurons. Supported by MEXT, Japan. [J Physiol Sci. 2008;58 Suppl:S12]
