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- Title
Short-Term Facilitation and Depression in the Cerebellum: Some Observations on Wild-Type and Mutant Rodents Deficient in the Extracellular Matrix Molecule Tenascin C.
- Authors
ANDJUS, PAVLE R.; BAJIĆ, ALEKSANDAR; ZHU, LAN; SCHACHNER, MELITTA; STRATA, PIERGIORGIO
- Abstract
Short-term plasticity was studied on synapses to Purkinje cells (PC): paired-pulse facilitation in parallel fibers (PF) and paired-pulse depression in climbing fibers (CF). Both phenomena relate to synaptic strength. These forms of short-term plasticity were tested on cerebellar slices in rat by early postnatal synchronous stimulation of olivary neurons (i.e., CFs) with harmaline and by inhibition of a metabotropic glutamate receptor (mGluR) as well as in mice that were deficient in the extracellular matrix glycoprotein tenascin-C. Harmaline stimulation delayed the developmental competition between CF inputs and maintained multiple innervation. Paired-pulse depression of the CFPC synapse after harmaline treatment was more expressed. However, pairedpulse facilitation in PF-PC synapses remained unchanged. Electrophysiological responses of postsynaptic mGluR1 in CF-PC synapses could be obtained only with AMPA receptors blocked and glutamate uptake impaired. The mGluR1-specific antagonist CPCCOEt suppressed the CF-mGluR EPSC in some PCs and potentiated it in other PCs. CF paired-pulse depression was not changed with CPCCOEt, thus excluding a presynaptic effect. The postsynaptic effect was underlined by CPCCOEt-induced rise in amplitude of EPSC and by a prolongation of its decay time. Tenascins are extracellular matrix glycoproteins that may restrict the regenerative capacity of the nervous tissue. Testing short-term presynaptic plasticity in tenascin-C-deficient mice showed that CF paired-pulse depression was less expressed while PF paired-pulse facilitation was augmented except in a group of cells where there was even depression. The results underline differences in forms of short-term plasticity with regard to susceptibility to diverse modulatory factors.
- Subjects
PURKINJE cells; SYNAPSES; ELECTROPHYSIOLOGY; TENASCIN; GLYCOPROTEINS
- Publication
Annals of the New York Academy of Sciences, 2005, Vol 1048, Issue 1, p185
- ISSN
0077-8923
- Publication type
Article
- DOI
10.1196/annals.1342.017