Hyperglycemia and mechanical allodynia observed in STZ-induced diabetic rats. (A) Following a single i.p. injection of STZ, the blood glucose level was significantly enhanced two weeks later. The enhancement persisted for at least another 7 weeks. (B) The growth rate of STZ rats was reduced. The body weight of control rats exhibited a steady increase, whereas the body weight of STZ rats remained unchanged. (C) PWTs in response to von Frey filament stimulation were significantly lowered two weeks after the STZ injection. The mechanical allodynia lasted for at least another 7 weeks. Data points are expressed as mean ± S.E.M. Error bars smaller than the size of the symbol are not shown. (*P < 0.05 vs. control, n = 12-15).