Analgesic Effect of the Lignans Compound Crystal-8 from Zanthoxylum Nitidum ( Roxb. ) DC. and the Relationship between Crystal-8 and Receptors / 医药导报

ABSTRACT

Objective To study whether crystal-8 exerts analgesic effect on the central nervous system,and to observe the relationship between crystal-8 and receptors. Methods A total of 32 SD rats were randomly divided into the 0.9% sodium chloride solution group, positive control group ( rotundine 2 mg·kg-1 ) , high dose of crystal-8 group ( 2 mg·kg-1 ) and low dose of crystal-8 group ( 1 mg · kg-1 ) . The changes of pain threshold were measured by the thermal stimulation test following intracerebroventricular (ICV) injection.The SD rats or mice were randomly divided into the 0.9% sodium chloride solution group, receptor tool medicine group ( including naloxone, reserpine, haloperidol, scopolamine) , crystal-8 group, receptor tool medicine plus crystal-8 group. The pain threshold was detected by the thermal stimulation test at 15, 30, 45, 60, 90, 120 min after dosing, then the influence of analgesic effect of crystal-8 on the neurotransmitter was observed. Results Compared with the 0.9% sodium chloride solution group, the pain threshold of rats was improved after taking the crystal-8 by intracerebroventricular (ICV) injection(P<0.01).Compared with the crystal-8 group, the naloxone plus crystal-8 group, the haloperidol plus crystal-8 group, the scopolamine plus crystal-8 group couldn't increase the pain threshold, there was no significant difference among these groups(P>0.05).However, Reserpine plus crystal-8 group could significantly decrease the pain threshold in rats compared with the crystal-8 group(P<0.01).The analgesic effect of crystal-8 was interfered by reserpine. Conclusion The analgesic effect of crystal-8 may be involved in the central mechanism,which relates to monoamine neurotransmitters, but has nothing to do with the opioid receptor, M receptor, and the inhibition of central DA receptor.