【摘要】 目的：观察降钙素对大鼠不同脑区痛阈的影响．方法：向大鼠不同脑区注射降钙素（ｃａｌｃｉｔｏｎｉｎ，Ｃａｌ），以辐射热甩尾阈值为指标测定痛阈变化．结果：Ｃａｌ侧脑室（ＶＬＣ）注射引起痛阈明显升高；同时发现向中脑导水管周围灰质（ｐｅｒｉａｑｕａｄｕｃｔａｌｇｒｅｙ，ＰＡＧ）注射Ｃａｌ，痛阈升高幅度更大，表明ＰＡＧ在Ｃａｌ的中枢镇痛效应中起重要作用．而向缰核（ｈａｂｅｎｕｌａ，Ｈａｂ）注射Ｃａｌ，痛阈降低．Ｃａｌ对痛阈的影响与脑内Ｃａ２＋有关．更多还原

【Abstract】 AIM: To study the effects of calcitonin (Cal) injected into different brain areas on pain threshold. METHODS: The analgesic effects of Cal were investigated in rats by the tail flick test. RESULTS: Cal injected into lateral cerebral ventricle (LCV) or periaqueductal gray (PAG) increased obviously the pain threshold to 49±22 % or to 68±12 % ( P <0 01), respectively. When PAG was blocked with lidocaine, the analgesic effect of Cal injected into LCV was lowered 41 ±9 %. Cal injected into habenula (Hab) de￣creas￣ed the pain threshold to -30±5 % ( P <0 01). CONCLUSION: Cal in different rat brain areas induced different effects on pain responses: analgesia or hyperalgesia, and showed that PAG played an important role in the analgesic effect induced by Cal, and the changing of pain threshold was mediated by the Ca 2+ in brain.更多还原