Effects of verapamil on hyperalgesia and spinal cord dorsal horn c-fos expression after trauma in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of verapamil on hyperalgesia and spinal cord dorsal horn c fos expression after trauma in rats Methods Forty Wistar rats weighing 160 220g were randomly divided into five groups with eight animals in each group Traumatic pain model was made by amputation of right hind limb 0 5cm below ankle joint In group A animals received intraperitoneal verapamil 10mg/kg after trauma; in group B fentanyl 30 ?g/kg; in group C verapamil 10mg/kg plus fentanyl 30?g/kg; in group D normal saline; in group E animals received neither trauma nor verapamil or fentanyl The pain threshold of the skin surrounding the site of trauma was measured at 15 min, 30 min,1h and 2h after trauma and the interval between the radiation heat applied to the skin over ankle and the withdrawal of the hind limb was taken as pain threshold Fos like immunoreactive (FLI) neurons were determined in 1 2 luminal of ipsilateral lumber spinal cord dorsal horn with FOS immunohistochemistry technique 2h after trauma Results The pain threshold of the skin surrounding trauma site decreased significantly at 15 min, 30 min, 1h and 2h after trauma (P