NMDA-, but not kainate- or quisqualate-dependent increases in cerebellar cGMP are dependent upon monoaminergic innervation.

As previously reported, intracerebellar injections of D-serine, quisqualate and kainate elevated mouse cerebellar cGMP levels. Similarly, activation of endogenous excitatory amino acid utilizing neurons with harmaline or pentylenetetrazole also increased cerebellar cGMP. We previously have demonstrated that the harmaline- and pentylenetetrazol-dependent cGMP increases are NMDA receptor mediated. In this report we further demonstrate that NMDA-dependent increases in cGMP are dependent upon monoaminergic innervation of the cerebellum, while kainate- and quisqualate-dependent cGMP increases are independent of such innervation.