Immediate and long-term effects of opiate antagonists on postictal behaviour following amygdala kindling in the rat

Abstract

Male Wistar rats implanted with bipolar electrodes in the amygdaloid complex were kindled. Subcutaneous injection of naloxone or naltrexone in low doses -0.12 and 0.24 mg/kg, respectively -dramatically reduced the postictal behavioural depression (BD) at 10 or 60 min. Remarkably, the BD was still reduced one day later. It would appear that the brain mechanisms involved in postictal BD use #-receptors since BD is quite sensitive to low doses of the preferential antagonists naloxone and naltrexone. The long-term effects, the most novel aspect of these studies, are probably related to immediate effects but could be produced through slow genomic processes or alteration of the response to endogenously released enkephalins.

Behavioral depression induced by an amygdala seizure and the opioid fentanyl was mediated through the nucleus accumbens

“…Previous studies showed that morphine increased the duration of postictal behavioral depression (Frenk et al., 1979; Hardy et al., 1980; Albertson et al., 1984), whereas systemic opioid antagonists, such as naloxone or naltrexone, reduced it (Frenk et al., 1979; Caldecott‐Hazard et al., 1983; Albertson et al., 1984; Cottrell & Bohus, 1987). Frenk et al.…”