Streptozotocin-induced diabetes in mice reduces the nociceptive threshold, as recognized after application of noxious mechanical stimuli but not of thermal stimuli.
We report herein that streptozotocin (STZ)-induced diabetes selectively alters the nociceptive threshold with respect to noxious mechanical stimuli. Mice were rendered diabetic by an injection of STZ (200 mg/kg, IV). In the tail-pinch test, the latency of the biting response to forceps was significantly decreased in animals with diabetes of 2 weeks and 8 weeks duration as compared to that in age-matched controls. However, the nociceptive threshold, as determined by the tail-flick test, was not significantly altered. The level of substance P in the spinal cord was significantly increased in mice that has been diabetic for 2 weeks, while, there was a significant decrease, as compared to control levels, in level of substance P in mice diabetic for 8 weeks. However, the level of somatostatin was not significantly altered in mice diabetic for either 2 weeks or 8 weeks. These data suggest that STZ-induced diabetes selectively alters a neuronal system that involves substance P but not somatostatin in the spinal cord.
Kamei
J
J
Department of Pharmacology, School of Pharmacy, Hoshi University, Tokyo, Japan.
Ohhashi
Y
Y
Aoki
T
T
Kasuya
Y
Y
D000818:Animals; D001835:Body Weight; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000503:physiopathology*; D006358:Hot Temperature; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009474:Neurons / Q000502:physiology; D010146:Pain / Q000378:metabolism / Q000503:physiopathology*; D010812:Physical Stimulation; D011930:Reaction Time / Q000187:drug effects; D012684:Sensory Thresholds / Q000502:physiology*; D013004:Somatostatin / Q000378:metabolism / Q000502:physiology*; D013116:Spinal Cord / Q000378:metabolism; D013373:Substance P / Q000378:metabolism / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology
D013373:Substance P; D013004:Somatostatin