Frequency detection and temporally dispersed synaptic signal association through a metabotropic glutamate receptor pathway.
74 - 77.
IN the classical view, a central neuron integrates incoming synaptic information by simple algebraic summation of the resultant bioelectrical signals that coincide in time, The voltage dependence of the NMDA (N-methyl-D-aspartate) type of ionotropic glutamate receptor endows neurons with an additional tool that allows one synaptic input to influence another, providing again, that the two are active simultaneously(1). Here we identify a new mechanism by which non-coincident signals generated by different synaptic inputs are integrated, The device serves to regulate neuronal excitation through G-protein-coupled, metabotropic glutamate receptors (mGluRs)(2) in a powerful and specific manner. We show that, in cerebellar Purkinje cells, a single activation of the climbing-fibre input markedly potentiates mGluR-mediated excitation at parallel-fibre synapses(3). The potentiation results; from a transient rise in cytosolic Ca2+ which is 'memorized' in such a way that it promotes excitation through mGluRs for about two minutes. A Ca2+-transient is also effective if imposed up to two seconds after parallel-fibre stimulation. By allowing temporally and spatially dispersed synaptic signals to be assimilated, this mechanism adds a new element to the computational power of central neurons.
|Title:||Frequency detection and temporally dispersed synaptic signal association through a metabotropic glutamate receptor pathway|
|Keywords:||CEREBELLAR PURKINJE-CELLS, LONG-TERM DEPRESSION, PROTEIN-KINASE-C, CALCIUM TRANSIENTS, CLIMBING FIBER, ACTIVATION, INVITRO, SLICES, INDUCTION, DENDRITES|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Life Sciences > Biosciences (Division of)
UCL > School of Life and Medical Sciences > Faculty of Medical Sciences > Medicine (Division of) > Wolfson Inst for Biomedical Research
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