title: Role of membrane cholesterol and lipid peroxidation in regulating the Na+/K+-ATPase activity in schizophrenia.
abstract: BACKGROUND
  Na+/K+-ATPase (NKA) activity is compromised in several neuropsychiatric disorders. Oxidative stress and membrane lipid composition play important roles in regulating NKA activity.
  
  
  OBJECTIVE
  The present study was undertaken to evaluate the effects of oxidative stress-induced membrane lipid damage and membrane cholesterol composition on NKA pump activity in schizophrenia.
  
  
  METHODS
  It was a hospital-based, cross-sectional, observational study in 49 cases and 51 controls for 1 year.
  
  
  METHODS
  NKA pump activity in red blood cell membrane, serum levels of thiobarbituric acid reactive substances (TBARS), protein carbonyl (PC) adducts, and cholesterol were measured by standard spectrophotometric techniques in newly diagnosed schizophrenia patients by Diagnostic and Statistical Manual of Mental Disorders, 4thEdition, Text Revision criteria. Membrane cholesterol was analyzed by chloroform and isopropanol extraction followed by measuring the cholesterol concentration by spectrophotometric technique.
  
  
  RESULTS
  Mean values for NKA pump activity, membrane cholesterol level, and serum cholesterol levels were significantly lower in the case group (P< 0.001). The activity of NKA pump was found to be directly correlated to membrane cholesterol level rather than with the serum cholesterol values. Although the NKA pump activity showed inverse relationship with the serum values of TBARS and PC products both, on multiple linear regression analysis, it was found to be significantly positively dependent on the membrane cholesterol (β = 0.268,P= 0.01) and negatively dependent on the serum TBARS (β = -0.63,P< 0.001) levels only.
  
  
  CONCLUSIONS
  Reduced membrane cholesterol and oxidative stress-induced damage to membrane lipids play crucial roles in decreasing the NKA activity in schizophrenia. Hence, for a better prognosis and treatment, measures are required to maintain optimum levels of cholesterol in neuronal tissues along with a proper control on oxidative stress.
authors.affiliation: Department of Biochemistry, Calcutta National Medical College, Kolkata, West Bengal, India.
authors.forename: Suparna
authors.initials: S
authors.lastname: Roy
authors.affiliation: Department of Biochemistry, Calcutta National Medical College, Kolkata, West Bengal, India.
authors.forename: Anindya
authors.initials: A
authors.lastname: Dasgupta
authors.affiliation: Department of Biochemistry, Calcutta National Medical College, Kolkata, West Bengal, India; Department of Biochemistry, North Bengal Medical College, Susrutanagar, Darjeeling, West Bengal, India.
authors.forename: Ushasi
authors.initials: U
authors.lastname: Banerjee
authors.affiliation: Department of Biochemistry, Calcutta National Medical College, Kolkata, West Bengal, India.
authors.forename: Piali
authors.initials: P
authors.lastname: Chowdhury
authors.affiliation: Department of Psychiatry, Calcutta National Medical College and Hospital, Kolkata, West Bengal, India.
authors.forename: Ashis
authors.initials: A
authors.lastname: Mukhopadhyay
authors.affiliation: Consultant Psychiatrist and Director, Clinic Brain, Barasat, West Bengal, India.
authors.forename: Gautam
authors.initials: G
authors.lastname: Saha
authors.affiliation: Department of Psychiatry, NRS Medical College, Kolkata, West Bengal, India.
authors.forename: Omprakash
authors.initials: O
authors.lastname: Singh
keywords: Lipid peroxidation; Na+/K+-ATPase activity; membrane cholesterol; schizophrenia