Thompson Alexis C, DiPirro Jean M, Sylvester Ahmad R, Martin Lisa B E, Kristal Mark B
Research Institute on Addictions, University of Buffalo, Buffalo, New York, USA.
J Am Assoc Lab Anim Sci. 2006 Nov;45(6):13-6.
Previous work in our laboratory showed that the recommended oral dose of buprenorphine (0.5 mg/kg) was not as effective as the standard therapeutic subcutaneous dose for postoperative analgesia in male Long-Evans (hooded) and Sprague-Dawley (albino) rats. The aim of the current study was to extend this analysis to female rats. We measured the pain threshold in adult female rats in diestrus or proestrus before and 30 and 60 min after oral buprenorphine (0.5 mg/kg,), the standard subcutaneous dose of buprenorphine (0.05 mg/kg), or vehicle only (1 ml/kg each orally and subcutaneously). Female rats showed an increased pain threshold (analgesia) after subcutaneous buprenorphine but no change in pain threshold after either oral buprenorphine or vehicle only. Estrous cycle stage (proestrus versus diestrus) did not affect the analgesic effects of buprenorphine, but rats in proestrus showed significantly lower pain thresholds (less tolerance to pain) than did those in diestrus. These results show that the oral dose of buprenorphine recommended for postoperative analgesic care does not induce significant analgesia in female rats and therefore is not as effective as the standard subcutaneous dose.
我们实验室之前的研究表明，对于雄性朗-埃文斯（带帽）大鼠和斯普拉格-道利（白化）大鼠，推荐的丁丙诺啡口服剂量（0.5毫克/千克）在术后镇痛方面不如标准治疗性皮下注射剂量有效。本研究的目的是将该分析扩展至雌性大鼠。我们测量了处于动情间期或动情前期的成年雌性大鼠在口服丁丙诺啡（0.5毫克/千克）、标准皮下注射剂量的丁丙诺啡（0.05毫克/千克）或仅给予赋形剂（口服和皮下注射均为1毫升/千克）之前以及之后30分钟和60分钟时的疼痛阈值。雌性大鼠在皮下注射丁丙诺啡后疼痛阈值升高（出现镇痛效果），但口服丁丙诺啡或仅给予赋形剂后疼痛阈值无变化。发情周期阶段（动情前期与动情间期）不影响丁丙诺啡的镇痛效果，但处于动情前期的大鼠疼痛阈值显著低于处于动情间期的大鼠（对疼痛的耐受性更低）。这些结果表明，推荐用于术后镇痛护理的丁丙诺啡口服剂量在雌性大鼠中不会诱导显著的镇痛效果，因此不如标准皮下注射剂量有效。
