Rani M A, Chandran U, Andrade C, Venkataraman B V
Department of Pharmacology, St. John's Medical College, Bangalore, India.
Indian J Exp Biol. 1996 Jul;34(7):663-6.
Tolerance to morphine analgesia was seen in diabetes. Calcium channel blockers potentiate opioid analgesia while calcium agonists antagonize. Therefore, the present study using thermal pain threshold was taken up to find out, whether felodipine, altered morphine analgesia in experimental diabetes. From the end of 6th week of streptozotocin-diabetes, felodipine was administered po for 2 week to half of the control and diabetic female rats. Morphine analgesia was recorded 1 hr after the first (acute effect) and last dose (chronic effect) of felodipine. Significant elevation of pain threshold was seen in the first 6 weeks in diabetic rats compared to controls. No tolerance was seen to morphine (2 mg/kg, sc) analgesia in diabetic rats. In both control and diabetic rats acute administration of felodipine produced significant analgesia while both acute and chronic administration of felodipine produced significant potentiation of morphine analgesia in control diabetic rats. The results suggest that prior felodipine may enhance morphine analgesia, and that this needs to be explored further in various types of pain.
糖尿病患者会出现对吗啡镇痛的耐受性。钙通道阻滞剂可增强阿片类药物的镇痛作用，而钙激动剂则起拮抗作用。因此，本研究采用热痛阈来探究非洛地平是否会改变实验性糖尿病大鼠的吗啡镇痛效果。从链脲佐菌素诱导糖尿病的第6周结束时起，对一半的对照雌性大鼠和糖尿病雌性大鼠口服给予非洛地平，持续2周。在首次（急性效应）和末次剂量（慢性效应）非洛地平给药1小时后记录吗啡镇痛效果。与对照组相比，糖尿病大鼠在最初6周内痛阈显著升高。糖尿病大鼠对吗啡（2mg/kg，皮下注射）镇痛未产生耐受性。在对照大鼠和糖尿病大鼠中，急性给予非洛地平均产生显著的镇痛作用，而急性和慢性给予非洛地平均使对照糖尿病大鼠的吗啡镇痛作用显著增强。结果表明，预先给予非洛地平可能增强吗啡镇痛作用，这需要在各种类型的疼痛中进一步探索。
