Abstract
Activity dependent regulation of AMPA receptor (AMPA-R) trafficking is one of the underlying bases of synaptic plasticity in hippocampus. However, detailed characteristics of AMPA-R trafficking has not yet been revealed in cerebellum. We addressed following issues: whether or not reduction mechanisms for AMPA-R activity through constitutive endocytosis share common features with those for long-term depression (LTD) in parallel fiber (PF) synapse in cerebellar Purkinje cell. Amplitude of PF-evoked EPSCs was reduced to 50-60% through constitutive endocytosis of AMPA-R, shown by intracellular application of Tetanus toxin (TeTX). Chelerythrine (10μM), a protein kinase C (PKC) inhibitor, suppressed TeTX-induced reduction in PF-EPSC amplitude. However, BAPTA (20mM) had no effect on this reduction in PF-EPSC amplitude. These results suggest that background activity of PKC is enough for constitutive endocytosis of AMPA-R. Furthermore, constitutive endocytosis is suggested to be independent of intracellular Ca2+ concentration. [Jpn J Physiol 54 Suppl:S142 (2004)]
