title: Altered Purkinje cell responses and calmodulin expression in the spontaneously ataxic mouse, Pogo.
abstract: Ataxia is often associated with altered cerebellar motor control, a process in which Purkinje cells (PCs) play a principal role. Pogo mice display severe motor deficits characterized by an ataxic gait accompanying hindlimb hyperextension. Here, using whole-cell patch-clamp recordings, we show that parallel fiber (PF)-excitatory post-synaptic currents (PF-EPSCs) are reduced, paired-pulse facilitation (PPF) is increased and PF-PC long-term depression (LTD) is impaired in Pogo mice; in contrast, climbing-fiber EPSCs are preserved. In control mice, treatment with the calmodulin antagonist calmidazolium (5 μm) impaired PPF and LTD. Notably, cerebellar calmodulin expression was significantly reduced in Pogo mice compared with control mice. Control PCs predominantly exhibited a tonic firing pattern, whereas the firing pattern in Pogo PCs was mainly a complex burst type. These results implicate alterations in PC responses and calmodulin content in the abnormal cerebellar function of Pogo mice.
authors.affiliation: Department of Physiology, Konyang University College of Medicine, Daejeon, Korea.
authors.forename: Kwan Young
authors.initials: KY
authors.lastname: Lee
authors.forename: Jin Seong
authors.initials: JS
authors.lastname: Kim
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Hyung Seo
authors.initials: HS
authors.lastname: Park
authors.forename: Young-Gil
authors.initials: YG
authors.lastname: Jeong
authors.forename: Nam-Seob
authors.initials: NS
authors.lastname: Lee
authors.forename: Dong Kwan
authors.initials: DK
authors.lastname: Kim
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001259:Ataxia / Q000378:metabolism* / Q000503:physiopathology*; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism; D036881:Long-Term Synaptic Depression / Q000502:physiology; D051379:Mice; D008817:Mice, Mutant Strains; D009473:Neuronal Plasticity / Q000502:physiology; D018408:Patch-Clamp Techniques; D011689:Purkinje Cells / Q000166:cytology / Q000502:physiology*; D013569:Synapses / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D002147:Calmodulin