关键词: 嘌呤碱基, 嘌呤核苷类, 痛阈

Abstract: Objective To determine the effect of purine bases and purine nucleosides on thermo-pain threshold and acute withdrawal in morphine dependent rats. Methods Twenty-eight Wistar rats were randomly divided into 4 groups: control group, morphine dependent group, morphine plus purine bases group and morphine plus purine nucleosides group, there were 7 rats per group. The tail flick test was used to determine the thermo-analgesic latency and naloxone was used to observe and evaluate the precipitated syndrome. Results In morphine, morphine plus adenine and guanine, and morphine plus adenosine and guanosine groups, significant antinociceptive effects were observed as compared with control group(P<0.05). In morphine plus aden ine and guanine, and morphine plus adenosine and guanosine groups, the latencies of tail flick were increased, while the counts of wet dog shakes and diarrhea or defecation were significantly higher than those in morphine dependent rats(P<0.05). Conclusion Adenine and guanine, as well as adenosine and guanosine can raise the basic thermo-analgesic threshold in chronic morphine dependent rats. Co-adminstration of large dosage of adenine and guanine or adenosine and guanosine together with morphine may aggravate some of the withdrawal symptoms.

Key words: purine bases, purine nucleosides, pain threshold