抄録
The type-1 metabotropic glutamate receptor (mGluR1) is required for motor learning and synaptic plasticity in cerebellar Purkinje neurons (PNs). Stimulation of parallel fibers (PFs) is known to elicit two distinct pathways via mGluR1α, an activation of Gq pathway and a direct activation of non-selective cation channels observed as a slow excitatory postsynaptic current (sEPSC). Cerebellum consists of ten lobules in mice and some functional differences between lobules have been reported. In this study we focused on the difference of sPSC between lobules in sagittal section of postnatal 15-17 days mice. We recorded from PNs by whole-cell patch clamp at -70 mV in the presence of blockers of AMPA and GABAA receptors. By applying tetanic stimulation (100 Hz 10 times) to PFs, we observed a transient inward current in lobule 9. The inward current reached a peak at 716 ± 126 ms (mean ± s.e.m) after stimulation and the amplitude was 190 ± 55 pA (n=5). In lobule 10, sEPSC was slower (1078 ± 178 ms) and smaller in amplitude (139 ± 64 pA), we also observed a faster transient outward current in lobule 10, but not in lobule 9. The time to peak was 272 ± 14 ms, and the amplitude was 44 ± 7 pA (n=5). Taken together, it was shown for the first time that PF stimulation-evoked slow PSCs of PNs in lobules 9 and 10 differ from each other. [J Physiol Sci. 2007;57 Suppl:S150]
