Neuronal Receptors (s) having Activation of mGluR1 in Purkinje cells causes a Ca-dependent release of a retrograde messenger, probably Glutamate, which acts on presynaptic ionotropic glutamatergic receptor (AMPA/kinate) on the parallel fibers (PFs), depolarizes PFs and modulates neurotransmission from parellel fibers to Purkinje cells as Publication facts