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Chinese Journal of Clinical Pharmacology and Therapeutics ›› 2019, Vol. 24 ›› Issue (7): 759-765.doi: 10.12092/j.issn.1009-2501.2019.07.006

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Effects of propofol on spinal cord GRPR of intrathecal morphine-induced pruritus model in rats

HENG Bingbing, DAI Shuyang, YANG Danfeng, BEEKOO Deepti, LIAN Qingquan, SHANGGUAN Wangning   

  1. Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital of WenZhou Medical University, Wenzhou 325027, Zhejiang, China
  • Received:2018-12-06 Revised:2019-05-05 Online:2019-07-26 Published:2019-07-29
  • About author:衡冰冰,女,硕士,研究方向:麻醉药理。 Tel: 15057767715 E-mail: 15057767715@163.com

Abstract:

AIM: To observe the effects of propofol on intrathecal morphine-induced pruritus in rats and explore the possible mechanism of propofol in treating intrathecal morphine-induced pruritus. METHODS: Thirty rats succeeded with intrathecal morphine-induced pruritus model, were randomly divided into 5 groups: 8 min group, 16 min group, 24 min group, 32 min group and 60 min group. 10 min after intrathecal injection with 40μg/kg morphine , rats were killed at 8 min, 16 min, 24 min, 32 min and 60 min thereafter, respectively to collect the dorsal spinal cord for Western blot. Forty-eightrats succeeded with intrathecal morphine-induced pruritus model, were randomLy divided into 4 groups: control group, propofol group, normal saline group and intralipid group. Same volume of normal saline 80 μL/kg, propofol 0.8 mg/kg, normal saline 80 μL/kg, intralipid 80 μL/kg were administered via the jugular vein to four groups respectively 10 min after intrathecal injection with normal saline or 40μg/kg morphine. Six rats were randomly selected from each group for pruritus behavior observation. The observation started from 30 min before up to 60 min after the intrathecal injection, and the injection scratching responses of the rat were recorded. The remaining rats in each group were executed after the intrathecal injection 42 min to collect the spinal cord for Western blot and immunohistochemistry to detect the protein concentration of GRPR. RESULTS:The peak of scratching frequency was at 10-20 min after morphine intrathecal injection, and almost disappeared at 60min. Compared with normal saline and intralipid groups, the scratching behavior was significantly decreased in propofol group (P<0.01); the expression of GRPR in spinal cord of control group and propofol group was lower (P<0.01). There was no significant difference of the expression of GRPR between normal saline group and intralipid group. CONCLUSION: Intrathecal injection of morphine-induced scratching behavior can be significantly alleviated by low-dose propofol. Propofol may significantly decrease the expression of GRPR in spinal cord in morphine-induced pruritus model.

Key words: pruritus, rat, morphine, propofol, GRPR

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