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Effect of intrathecal or intracerebroventricular administrition of ofq on pain threshold and acpuncture analgesia in rats

Zhang Xiulin, Zhu Chongbin, Xu Shaofen, Cao Xiaoding, Wu Gencheng, Li Moyi, Cui Dafu, Chi Chengwu

State Key Labratory of Medical Neurobiology, Shanghai Medical University. Shanghai 200032, China；Shanghai Institute of Biochemistry, Chinese Academy of Science. Shanghai 200031, China

Abstract

Orphanin FQ (OFQ) is a newly discovered 17-amino-acid peptide capable of inducing hyperalgesia.In the present study, the effects of OFQ on basal pain threshold and acupuncture anlgesia (AA) in rats were observed using the tail-flick tesl. It was found that intrathecal (IT) or intracerebroventricular (ICV) administrition of 0.1 #mu#g OFQ had no effect on basal pain threshold of rats, while 1 #mu#g OFQ could lower the threshold. However, OFQ at both the doses (0.1 or 1.0 #mu#g) administered by either IT or ICV injection could antagonize AA with that occuring in the brain being more prominent then in the spinal cord. When the rats were repeatedly treated with antisense oligonucleotide to block synthesis of OFQ receptor, pain threshold increased significantly.At such instance, when the OFQ was combined with acupuncture, the effect of AA showed no obvious change. The above results show that the OFQ at small dose has no effect on pain threshold but can lower it at larger d0se; while in both cases OFQ can antagonize AA.

Key words: Orphanin FQ;Pain modulation;Anti-sense oligonucleotide;Central nervous system;Acupuncture analgesia

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Citing This Article：

Zhang Xiulin, Zhu Chongbin, Xu Shaofen, Cao Xiaoding, Wu Gencheng, Li Moyi, Cui Dafu, Chi Chengwu. Effect of intrathecal or intracerebroventricular administrition of ofq on pain threshold and acpuncture analgesia in rats. Acta Physiol Sin 1997; 49 (5): (in Chinese with English abstract).