Benedek G, Szikszay M
Prog Neuropsychopharmacol Biol Psychiatry. 1985;9(4):369-80. doi: 10.1016/0278-5846(85)90189-7.
Rats were subjected to prolonged footshock, intensive acoustic stress, cold water swim and restraint over a period of 10 days. The analgesic and thermoregulatory properties of morphine (2, 4 and 8 mg/kg, sc.) were tested on the 11th day. Analgesia assessment was performed by means of hot-plate (HP) and tail-flick (TF) tests, and body temperature (Tb) changes was measured. Prolonged footshock and acoustic stress increased the sensitivity to morphine, while repeated restraint lessened morphine's effect. Cold water swim caused ambiguous consequences, facilitated the effect of a small dose of morphine, but reduced that of a large dose. It was concluded that the sensory components of the stressful exposure determine the effects of repeated stress on morphine sensitivity. Whereas painful interventions led to sensitization, and non-painful procedures result in tolerance to morphine's effects. The finding that analgesic and thermoregulatory effects of morphine were simultaneously enhanced supports the contention that the mechanism of sensitization to opiates involves a site where pathways mediating opiate analgesia and thermoregulatory effects converge.
大鼠在10天的时间里接受长时间足部电击、强烈声音应激、冷水游泳和束缚。在第11天测试吗啡（2、4和8毫克/千克，皮下注射）的镇痛和体温调节特性。通过热板（HP）和甩尾（TF）试验进行镇痛评估，并测量体温（Tb）变化。长时间足部电击和声音应激增加了对吗啡的敏感性，而反复束缚则减弱了吗啡的作用。冷水游泳产生了不明确的结果，增强了小剂量吗啡的作用，但减弱了大剂量吗啡的作用。得出的结论是，应激暴露的感觉成分决定了反复应激对吗啡敏感性的影响。疼痛性干预导致致敏，而非疼痛性程序导致对吗啡作用的耐受性。吗啡的镇痛和体温调节作用同时增强这一发现支持了这样一种观点，即对阿片类药物致敏的机制涉及介导阿片类镇痛和体温调节作用的途径汇聚的部位。
