脑钠肽镇痛作用及机制的研究

目的：研究脑钠肽（ｂｒａｉｎｎｅｔｒｉｕｒｅｔｉｃｐｅｐｔｉｄｅ，ＢＮＰ）的镇痛作用及机制。方法：在小鼠热板、扭体和甲醛试验上，分别观察用药后舔足潜伏期、扭体数及疼痛评分的变化。一氧化氮（ＮＯ）用ｇｒｅｅｎ法测定。结果：ＢＮＰ（２５，５０，１００μｇ·ｋｇ－１，ｉｐ）能显著延长小鼠舔足潜伏期，并呈量效关系，其ｉｐＥＤ５０为３８．６μｇ·ｋｇ－１；ｉｐ２５、５０μｇ·ｋｇ－１ＢＮＰ显著减少小鼠扭体数和脑组织中ＮＯ含量；ｉｐ５０μｇ·ｋｇ－１和ｉｃｖ２μｇ·ｋｇ－１ＢＮＰ均可显著抑制甲醛致小鼠疼痛，降低疼痛评分，进一步发现ＢＮＰ的镇痛作用可被ＥＧＴＡ加强，ＣａＣｌ２拮抗，但维拉帕米可部分逆转ＣａＣｌ２对ＢＮＰ镇痛的拮抗。结论：ＢＮＰ有显著镇痛作用，其镇痛作用可被Ｃａ２＋影响。

The studies on analgesic action of brain natriuretic peptide and its mechanism

AIM: To study the analgesic effect of brain natriuretic peptide(BNP) and its mechanism. METHODS: On the hot plate, writhing and methyl aldehyde test in mice, the changes of the latencies of licking paws, the writhing numbers and pain score were observed respectively after administrating drugs. The content of nitric oxide(NO) was measured with Green method. RESULTS: BNP(25,50,100 μg·kg-1,ip) could significantly and dose dependently prolong the latencies of licking paws, the ED50 of ip BNP was 386 μg·kg-1; BNP 25,50 μg·kg-1 ip markedly decreased the writhing numbers and the content of NO in the cerebrum; Both ip 50 μg·kg-1 and icv 2 μg·kg-1 BNP could inhibit the pain induced by methyl aldehyde in mice and reduce the pain score. It was further found that analgesic action of BNP could be antagonized by CaCl2 and enhanced by EGTA, and verapamil partilly overturned the antagonism of CaCl2 on the analgesic action of BNP. CONCLUSION: BNP has significant analgesic action and its mechanism may be influenced by calcium ion.