KIR current inactivation modulates dendritic calcium in medium spiny neurons
© Steephen and Manchanda; licensee BioMed Central Ltd. 2009
Published: 13 July 2009
The membrane potential of striatal medium spiny neurons (MSNs) fluctuates between down- and up-states. In ventral striatum, inward rectifying potassium (KIR) currents in 40% of MSNs inactivate . KIR current inactivation appears to alter spike frequency and onset during up-states . However, it is not known whether these translate into significant changes in calcium dynamics in the dendrites. We describe a computational study investigating how this inactivation influences dendritic calcium transients.
Two MSNs were modeled using NEURON, one equipped with non-inactivating KIR currents (henceforth, "non-inKIR") and the other with inactivating KIR currents (henceforth "inKIR") and their dendritic calcium transients were compared in response to injected current and synaptic inputs. Measurements were made from the distal dendrites.
The facilitatory effect of KIR current inactivation on dendritic calcium influx appears to be mediated through action potential firing frequency and their timing. In view of the reports that dendritic intracellular calcium levels influence cortico-striatal input plasticity , our findings suggest that KIR current inactivation may significantly modulate synaptic plasticity.
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