Preferential expression of plasmalemmal K-dependent Na+/Ca2+ exchangers in neurons versus astrocytes

Neuroreport. 2002 Aug 27;13(12):1529-32. doi: 10.1097/00001756-200208270-00008.


Numerous isoforms of plasmalemmal K-dependent (NCKX) and K-independent (NCX) Na+/Ca2+ exchangers are expressed in the brain. The physiological functions of each isoform are presently unknown. Therefore, in this study, we compared expression of NCKX and NCX transcripts between primary cultures of cerebellar granule cells, and astrocytes. Northern blot analysis showed that granule cells expressed NCKX2, NCKX3, NCKX4 and NCX3, whereas astrocytes expressed primarily NCX1. Consistent with this molecular characterization, a significant fraction of 45Ca2+ accumulation in Na-loaded granule cells, but not in astrocytes, depended on external K+. This is the first demonstration of native NCKX activity in neurons derived from the central nervous system. Our data suggest that NCKX isoform expression may correspond to the unique Ca2+ homeostasis requirements of neurons.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Astrocytes / chemistry
  • Astrocytes / cytology
  • Astrocytes / metabolism*
  • Calcium / metabolism
  • Calcium Radioisotopes / pharmacokinetics
  • Cells, Cultured
  • Cerebellum / cytology
  • Gene Expression / physiology
  • Immunohistochemistry
  • Neurons / chemistry
  • Neurons / cytology
  • Neurons / metabolism*
  • Potassium / pharmacology
  • RNA, Messenger / analysis
  • Rats
  • Rats, Sprague-Dawley
  • Sodium / metabolism
  • Sodium-Calcium Exchanger / analysis
  • Sodium-Calcium Exchanger / genetics*
  • Sodium-Calcium Exchanger / metabolism


  • Calcium Radioisotopes
  • RNA, Messenger
  • Slc24a3 protein, rat
  • Sodium-Calcium Exchanger
  • potassium-dependent sodium-calcium exchanger
  • Sodium
  • Potassium
  • Calcium