Propofol suppresses formalin stimulation -induced c-fos gene expression in the rat spinal cord / 中华麻醉学杂志

ABSTRACT

Objective To investigate whether spinal cord is involved in the analgesic effect of propofol.Methods Fifteen adult SD rats of both sexes weighing 195～223g were randomly divided into three group of five animals each control group received normal saline intraperitoneally(ip), fentanyl group received fentanyl 0 1mg/kg and propofol group propofol 100mg/kg ip 2 min later 4% formalin 150?l was injected subcutaneously into the planta region of right hindpaw 1h after formalin injection animals of all three groups were anesthetized with pentobarbital sodium ip After induction of anesthesia chest was open and 100 ml of normal saline was infused via left ventricle then followed by 4% formalin infusion for fixation of tissue, 90 min later spinal cord, L 3 5 sect, was removed for determination of c fos expression in spinal cord using fos immunohistochemistry technique Results In control group in less than 10 s after formalin intraplantar injection the animals were agitated, restless, lame and paw licking In fentanyl group and propofol group the righting reflex was suppressed for (19 4?7 8) min and (7 2?1 5)min and no pain response was seen during this period When righting reflex recovered the pain response was much lighter than that in the control group Formalin stimulation induced c fos expression was seen only in the ipsilateral spinal cord Both fentanyl and propofol significantly suppressed c fos expression evoked by formalin stimulation The number of fos like immunoreactivity neurons(FLIN) decreased by 57 8% and 36 3% respectively(P