FIGURE 8.

Hypothetical scheme of adenosine-mediated attenuation of reciprocal synapses in mitral cells. (A) Recurrent inhibition. (B) Adenosine activates A₁ receptors in mitral cell dendrites, which leads to inhibition of voltage-activated calcium channels (VACC) of the N-type and P/Q-type. The reduction of calcium influx decreases the amount of glutamate released by mitral cells, resulting in reduced excitation of interneurons (granule cells and parvalbumin interneurons) as well as reduced self-excitation. The reduction of interneuron excitation attenuates GABA release and, hence, recurrent inhibition.