Diabetes-induced alterations in calcium homeostasis in sensory neurones of streptozotocin-diabetic rats are restricted to lumbar ganglia and are prevented by neurotrophin-3

Diabetologia. 2002 Apr;45(4):560-70. doi: 10.1007/s00125-002-0785-x.


Aims/hypothesis: In diabetic sensory polyneuropathy the earliest and most severe pathophysiology occurs in neurones with the longest axons. The aim of this study was to characterise a diabetes-induced neurodegenerative marker that was selective for sensory neurones with the longest axons. We studied alterations in calcium homeostasis since this occurs in other neurodegenerative diseases.

Methods: Sensory neurones were cultured from control and streptozotocin-diabetic rats, treated with or without human recombinant neurotrophin-3 (hrNT-3), and neurones from L4-L6 dorsal root ganglia (DRG) which exhibit the longest axons in vivo were compared with those from C5-L3 DRG. Fluorescent video-imaging was used to measure cytoplasmic calcium dynamics.

Results: Streptozotocin diabetes of 8 to 14 weeks, induced an increase in resting internal Ca(2+) concentration ([Ca(2+)](i)), from 67 +/- 7 nmol/l in small neurones and 79 +/- 9 nmol/l in big neurones obtained from control animals to 214 +/- 19 nmol/l in small neurones and 273 +/- 30 nmol/l in big neurones after 14 weeks of diabetes ( p < 0.05) in L4-L6 DRG cultures. Neurones from C5-L3 ganglia and non-neuronal cells were not affected. Treatment of 14-week streptozotocin-diabetic rats with subcutaneous injection of 5 mg/kg NT-3 normalised the increase in resting [Ca(2+)](i). The amplitudes induced by depolarisation, caffeine and ATP [Ca(2+)](i) responses were reduced in small ( < 30 microm diameter) but not big ( > 35 microm diameter) neurones of L4-L6 DRG from streptozotocin-diabetic animals; the C5-L3 DRG were not similarly affected and the changes in the L4-L6 DRG were corrected by NT-3 treatment.

Conclusions/interpretation: Altered calcium homeostasis could be an early molecular marker linked to the onset of diabetic sensory neuropathy. This neurodegenerative index can be corrected by NT-3 therapy and should encourage further work aimed at understanding the mechanistic basis of these observations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Animals
  • Caffeine / pharmacology
  • Calcium / metabolism*
  • Calcium Signaling / drug effects
  • Calcium Signaling / physiology*
  • Diabetes Mellitus, Experimental / physiopathology*
  • Ganglia, Spinal / drug effects
  • Ganglia, Spinal / physiopathology*
  • Homeostasis / drug effects
  • In Vitro Techniques
  • Male
  • Neurons, Afferent / drug effects
  • Neurons, Afferent / physiology*
  • Neurotrophin 3 / pharmacology*
  • Rats
  • Rats, Wistar
  • Time Factors


  • Neurotrophin 3
  • Caffeine
  • Adenosine Triphosphate
  • Calcium