• 作者： 廖志飛; 陳介甫
• 作者服務機構： 國立陽明醫學院藥理學科及榮民總醫院醫學研究部
• 中文摘要： 本研究觀察腹腔給予 Ketamine（5 － 30 mg/kg），對大白鼠之活動性、禁水引發之喝水行為、20次反應後得水為賞（FR20）之工具反應行為及以電刺激引發之連續避免行為（兩次電刺激之間隔及反應與電刺激之間隔均為20秒）之影響。實驗中，FR20工具反應行為之平均反應率為每秒1.32次而於連續避免行為則為每秒0.06次。結果顯示 Ketamine（10－30 mg/kg）可因劑量之加大而加強動物之活動性，但降低FR20之工具反應行為。雖然 Ketamine 顯著地抑制禁水引發之喝水行為，但它對於以水當獎賞之FR20工具反應行為之降低作用，似乎並非由於減少口渴所引發之飲水動機所致。較低劑量（10與15 mg/kg）之 Ketamine 可有效地增加避免電刺激之反應而伴隨著減少電刺激次數，但較大劑量（30 mg/kg）則顯著地降低連續避免反應行為。由此可見 Ketamine 可抑制較高反應速率之 FR20 工具反應行為而促進較低反應速率之連續避免行為。從上述之結果及別人報導之結果顯示 Ketarnine 對於動物之受程式控制之行為（Schedule－controlled behavior）有很特別的作用，更重要的於有效劑量下之作用與受程式控制行為之反應速率有關。
• 英文摘要： Effects of ketamine (5-30 mg/kg, i.p.) on locomotor activity, drinking behavior induced by waterdeprivation, responding under 20 responses fixed-ratio (FR 20) schedule of water presentation, and re-sponding under a continuous-avoidance schedule (shock-shock interval and response-shock interval were20 seconds) were studied in rats. The mean control rate of responding under FR 20 schedule was 1.32responses/sec and that of continuous-avoidance schedule was 0.06 responses/sec. Ketamine (10-30 mg/kg)significantly enhanced locomotor activity while decreased responding under FR 20 schedule of waterpresentation in a dose-related fashion. Although ketamine significantly changed drinking behavior inducedby water deprivation, the rate-decreasing effect of ketamine on operant responding maintained by waterreinforcement was unlikely to result from a decrease in thirst motivation. Lower effective doses (10 and15 mg/kg) of ketamine significantly increased postshock responses with concomitant decrease in shockrate, whereas higher dose (30 mg/kg) decreased the responding maintained under a continuous-avoidanceschedule. Therefore, ketamine increased the lower rate of responding under a continuous-avoidance sched-ule while decreased the higher rate of responding under FR 20 schedule. From these and other reportedresults it may be concluded that ketamine affects schedule-controlled operant behavior in characteristicways, depending on the control rate of responding at some effective doses range.
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