A potassium channel blocker induces a long-lasting enhancement of corticostriatal responses.
Disruptions in synaptic plasticity in the dorsal striatum may contribute to the pathophysiology underlying Parkinson's disease. Here we report a novel, chemically-induced form of plasticity induced by application of the potassium channel blocker tetraethylammonium (TEA) in the dorsolateral striatum of the adult rat. Transient application of TEA persistently increased synaptically-evoked extracellularly-recorded corticostriatal responses in an activity-, concentration- and time-dependent manner. Pharmacological experiments suggest that this plasticity is dependent on L-type calcium channel and protein kinase C (PKC) activation. Striatal dopamine depletion induced by nigrostriatal dopamine lesions with 6-hydroxydopamine significantly reduced, but did not abolish, TEA-mediated enhancement of the corticostriatal response. Intracellular recordings demonstrate that this TEA-mediated plasticity is associated with an increase in EPSP size and slope, as well as input resistance. Collectively, these findings demonstrate a novel form of L-type calcium channel-dependent plasticity in the adult dorsal striatum that is induced in the absence of dopaminergic input.
Norman
Eric D
ED
Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0615, USA.
Egli
Regula E
RE
Colbran
Roger J
RJ
Winder
Danny G
DG
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects* / Q000502:physiology; D003342:Corpus Striatum / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019789:Tetraethylammonium / Q000494:pharmacology; D013997:Time Factors
D026902:Potassium Channel Blockers; D019789:Tetraethylammonium