Morphine and Naloxone Effects on Seizure in Brain Slice of Morphine-Dependent Infant Mice

The aim of this study was to evaluate the effects of different concentrations of morphine and naloxone on epileptic activity in live brain slices taken from morphine-dependent and control infant mice.
Forty neonatal mice were randomly selected. To establish dependency, 2, 4, 8, 16 and 32 mg / kg morphine was injected subcutaneously once daily (0.1 cc) for 5 consecutive days from day 14-18 after birth. On postnatal days 19-20, brain slices were prepared and cerebrospinal fluid was perfused with low magnesium to induce experimental- epiletform activity. The effects of 10, 100 and 1000 µM concentrations of morphine and 10 µM naloxone were investigated on epileptic activity. Chenges in the number as well as onset and amplitude of activities were considered as an indicator to determine the quantity of their effect.
The results showed that morphine 100 µM increased the activity while 10 and 1000 µM concentrations of morphine and 10 µM naloxone attenuated epileptic activity in both groups. Naloxone reduced pro-seizure effect of morphine, but anti-seizure effect of morphine couldnt restored by naloxone.
Morphine has a two-phase concentration-dependent effect on epileptic activity in the infant mice; so that low and high concentrations of morphine inhibit epileptic activity, but its moderate concentration potentiates the epileptic activity. Naloxone has an anti-seizure effect.