Hyperalgesia and decreased neuronal nitric oxide synthase in diabetic rats

Neuroreport. 1998 Jan 26;9(2):243-7. doi: 10.1097/00001756-199801260-00013.


To evaluate the role of nitric oxide synthase (nNOS) in the pathogenesis of diabetic neuropathy, we investigated nociception and nNOS expression in dorsal root ganglion (DRG) of rats with streptozocin-induced diabetes. Paw withdrawal threshold to noxious mechanical stimuli was decreased in both L-NAME-treated and diabetic rats. The number of NADPH-diaphorase positive neurons was significantly decreased in untreated diabetic compared with control rats. Decreased expression of nNOS protein was confirmed by immunoblotting. Insulin treatment completely prevented decreases in withdrawal threshold and nNOS expression. Cyclic GMP content paralleled nNOS expression in experimental animals. These results suggest that decreased nNOS-cGMP system in DRG may play a role in the pathogenesis of diabetic sensory neuropathy.

MeSH terms

  • Animals
  • Blotting, Western
  • Cyclic GMP / metabolism
  • Diabetes Mellitus, Experimental / complications*
  • Diabetes Mellitus, Experimental / enzymology
  • Diabetes Mellitus, Experimental / psychology
  • Diabetic Neuropathies / enzymology*
  • Enzyme Inhibitors / pharmacology
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / enzymology
  • Histocytochemistry
  • Hyperalgesia / enzymology
  • Hyperalgesia / etiology*
  • Hyperalgesia / psychology
  • Male
  • NG-Nitroarginine Methyl Ester / pharmacology
  • Neurons / enzymology*
  • Nitric Oxide Synthase / antagonists & inhibitors
  • Nitric Oxide Synthase / metabolism*
  • Pain Measurement
  • Rats
  • Rats, Sprague-Dawley


  • Enzyme Inhibitors
  • Nitric Oxide Synthase
  • Cyclic GMP
  • NG-Nitroarginine Methyl Ester