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Thiamine Deficiency Increases Intrinsic Excitability of Mouse Cerebellar Purkinje Cells.

Authors
  • Bolaños-Burgos, Ivonne Carolina1
  • Bernal-Correa, Ana María2
  • Mahecha, Germán Arturo Bohórquez3
  • Ribeiro, Ângela Maria1, 4
  • Kushmerick, Christopher5, 6, 7
  • 1 Graduate Program in Neuroscience, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. , (Brazil)
  • 2 Graduate Program in Physiology and Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. , (Brazil)
  • 3 Department of Morphology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. , (Brazil)
  • 4 Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. , (Brazil)
  • 5 Graduate Program in Neuroscience, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. [email protected] , (Brazil)
  • 6 Graduate Program in Physiology and Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. [email protected] , (Brazil)
  • 7 Department of Physiology and Biophysics, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. [email protected] , (Brazil)
Type
Published Article
Journal
Cerebellum (London, England)
Publication Date
Apr 01, 2021
Volume
20
Issue
2
Pages
186–202
Identifiers
DOI: 10.1007/s12311-020-01202-x
PMID: 33098550
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

Thiamine deficiency is associated with cerebellar dysfunction; however, the consequences of thiamine deficiency on the electrophysiological properties of cerebellar Purkinje cells are poorly understood. Here, we evaluated these parameters in brain slices containing cerebellar vermis. Adult mice were maintained for 12-13 days on a thiamine-free diet coupled with daily injections of pyrithiamine, an inhibitor of thiamine phosphorylation. Morphological analysis revealed a 20% reduction in Purkinje cell and nuclear volume in thiamine-deficient animals compared to feeding-matched controls, with no reduction in cell count. Under whole-cell current clamp, thiamine-deficient Purkinje cells required significantly less current injection to fire an action potential. This reduction in rheobase was not due to a change in voltage threshold. Rather, thiamine-deficient neurons presented significantly higher input resistance specifically in the voltage range just below threshold, which increases their sensitivity to current at these critical membrane potentials. In addition, thiamine deficiency caused a significant decrease in the amplitude of the action potential afterhyperpolarization, broadened the action potential, and decreased the current threshold for depolarization block. When thiamine-deficient animals were allowed to recover for 1 week on a normal diet, rheobase, threshold, action potential half-width, and depolarization block threshold were no longer different from controls. We conclude that thiamine deficiency causes significant but reversible changes to the electrophysiology properties of Purkinje cells prior to pathological morphological alterations or cell loss. Thus, the data obtained in the present study indicate that increased excitability of Purkinje cells may represent a leading indicator of cerebellar dysfunction caused by lack of thiamine.

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