Alteration of Synaptosomal Plasma Membrane Cholesterol Content: Membrane Physical Properties and Cation Transport Proteins

H. K. Shapiro, R. L. Barchi

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Abstract: The level of nerve membrane cholesterol was altered by in vitro incubation of rat brain synaptosomal plasma membrane with liposomes having varying cholesterol contents. The normal plasma membrane cholesterol/phospholipid ratio of 0.3–0.4 (mol/mol) could be decreased by about one‐half or increased more than 100%. Fluorescence polarization measurements were made using the probe 1,6‐diphenyl‐1,3,5‐hexatriene. At temperatures below 35°C, lowering membrane cholesterol led to increased apparent microviscosity, while raising cholesterol content produced little change. However, at 45°C a continuous direct relationship existed between experimental membrane cholesterol/phospholipid ratio (ranging from 0.18 to 0.73) and apparent microviscosity. Under standard liposome‐synaptosomal plasma membrane exchange conditions, 80% of the initial specific [3H]saxitoxin binding activity to the voltage‐dependent sodium channel and at least 95% of the (Mg2+,K+)‐p‐nitrophenylphosphatae activity were preserved. Our results indicate that neither the characteristics of toxin binding nor the kinetics of this enzyme activity is dependent upon membrane cholesterol content.

Original languageEnglish (US)
Pages (from-to)1813-1818
Number of pages6
JournalJournal of neurochemistry
Volume36
Issue number5
DOIs
StatePublished - May 1981
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Cellular and Molecular Neuroscience

Keywords

  • (Na,K)‐Adenosine triphosphatase
  • Cholesterol
  • Membrane fluidity
  • Sodium channel protein
  • Synaptosomal plasma membrane

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