大鼠脊髓内甲啡肽、强啡肽A-(1—13)和吗啡在镇痛中的相互加强作用

1.大景以辐射热甩尾法测痛。应用脊髓蛛网膜下腔,连续累加注射法观察药物的镇痛作用。脊髓蛛网膜下腔单独注射甲啡肽100nmol不能提高痛阈,但与吗啡或强啡肽A-(1—13)合用时,可明显加强后者的镇痛作用。 2.脊髓蛛网膜下腔单独注射强啡肽A-(—13)2.5nmol本身无镇痛作用,但与吗啡合用时,却能明显加强吗啡的镇痛作用。 3.本文对连续累加注射法的特点及三类阿片受体及其配基对痛觉的调制作用,进行了讨论。

MUTUAL POTENTIATION OF THE ANALGESIC EFFECTS OF [MET~5] ENKEPHALIN,DYNORPHIN A-(1--13) AND MORPHINE IN THE SPINAL CORD OF THE RAT

1. Nociception of the rat was assessed by measuring the tail flick latency (TFL)with thermal irradiation. Drugs were administered intrathecally in serially increas-ing doses to observe their analgesic effect. Intrathecal injection of 100 nmol ofmet~5] enkephalin (MEK) alone produced no significant increase in TFL. However,when the subthreshold dose of MEK was administered in combination withmorphine or dynorphin A-(1--13), a marked potentiation of the analgesic effectof the latter two was observed. 2. While 2.5 nmol of dynorphin A-(1--13) alone produced no significantincrease in TFL after its intrathecal injection, it potentiated the analgesic effectproduced by serially increasing doses of morphine. 3. The methodology of serial intrathecal injections of increasing doses of drugs,as well the mutual influence of ligands specific for 3 types of opioid receptors in painmodulation are discussed.