Role of vanilloid VR1 receptor in thermal allodynia and hyperalgesia in diabetic mice

We examined the role of the vanilloid VR1 receptor in the thermal hyperalge sia and allodynia seen in diabetic mice. Tail-flick latencies at source vol tages of 35 and 50 V for a 50-W projection bulb in diabetic mice were signi ficantly shorter than those in non-diabetic mice. Tail-flick latencies at 3 5 and 50 V in diabetic mice were increased by pretreatment with anti-vanill oid VR1 receptor serum. Intrathecal(i.t.) injection of anti-VR1 serum resul ted in a significant increase in the tail-flick latency at 50 V in non-diab etic mice. However, i.t. pretreatment with anti-vanilloid VR1 receptor seru m did not affect the tail-flick latency at a heat intensity of 35 V in non- diabetic mice. Thus. it seems likely that thermal allodynia and hyperalgesi a in diabetic mice may be due to the sensitization of vanilloid VR1 recepto rs in primary sensory neurons in the spinal cord. (C) 2001 Elsevier Science B.V. All rights reserved.