Abstract

Aims

The present study attempts to evaluate the effects of different doses of morphine on experimental epileptiform activity caused by pentylenetetrazol (PTZ) in rats.

Methods

Thirty adult male rats were assigned to saline (n = 5), morphine (2, 5, and 10 mg/kg, n = 15), naloxone (1 mg/kg, n = 5), and pre-treated with naloxone₊morphine (1 + 10 mg/kg, n = 5) groups. The animals were anesthetized with ketamine + xylazine (80 + 8 mg/kg), and then a bipolar electrode was implanted into the CA1 (AP: −2.76 mm, ML: −1.4 mm and DV: 3 mm). To evaluate the effects of drugs on spike count and their amplitudes by elab amplifier, after drug administration for 25 min, PTZ (80 mg/kg, i.p.) was injected to induce epileptiform activity. Finally, diazepam (10 mg/kg) was used to suppress epileptic activity.

Results

The results revealed that morphine at a dose of 2 mg/kg decreased, and at doses of 5 and 10 mg/kg had an increasing effect on seizure-like events (SLEs). Nevertheless, morphine at a dose of 10 mg/kg enhanced SLEs significantly (p < 0.01). Naloxone at a dose of 1 mg/kg had no significant effect on the spike count but increased amplitude of them (p < 0.001). Moreover, being pretreatment with naloxone at a dose of 1 mg/kg, the morphine group showed significantly increased in the spike count (p < 0.05).

Conclusions

Morphine has biphasic effects on PTZ-induced epileptiform activities that way at a low dose has an inhibitory effect, but if the dose is increased, it will intensify the desired event and that the stimulatory effects of morphine appear not to be via opioid receptors.

中文翻译：

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吗啡对戊四唑致大鼠癫痫活性的刺激和抑制作用

摘要

宗旨

本研究试图评估不同剂量的吗啡对戊四唑 (PTZ) 引起的大鼠实验性癫痫样活动的影响。

方法

将 30 只成年雄性大鼠分配到生理盐水 ( n  = 5)、吗啡 (2、5 和 10 mg/kg，n  = 15)、纳洛酮 (1 mg/kg，n  = 5)，并用纳洛酮₊吗啡 (1 + 10 mg/kg, n  = 5) 组。用氯胺酮 + 甲苯噻嗪 (80 + 8 mg/kg) 麻醉动物，然后将双极电极植入 CA1（AP：-2.76 mm，ML：-1.4 mm 和 DV：3 mm）。为了通过 elab 放大器评估药物对尖峰计数及其振幅的影响，在给药 25 分钟后，注射 PTZ (80 mg/kg, ip) 以诱导癫痫样活动。最后，地西泮 (10 mg/kg) 用于抑制癫痫活动。

结果

结果显示，2 mg/kg 剂量的吗啡降低，而 5 和 10 mg/kg 剂量的吗啡对癫痫样事件 (SLE) 的影响增加。然而，10 mg/kg 剂量的吗啡显着增强了 SLE（p  < 0.01）。1 mg/kg 剂量的纳洛酮对尖峰计数没有显着影响，但增加了它们的幅度（p  < 0.001）。此外，在用 1 mg/kg 剂量的纳洛酮进行预处理后，吗啡组的尖峰计数显着增加 ( p  < 0.05)。

结论

吗啡对 PTZ 诱导的癫痫样活动具有双相作用，即在低剂量时具有抑制作用，但如果增加剂量，则会加剧所需的事件，并且吗啡的刺激作用似乎不是通过阿片受体。