Epileptogenesis and muscular hypertonic postictal phenomena induced by naloxone in intact cats

Epileptogenesis produced by repeated i.p. administration of naloxone chloride and sensory stimulation (photoacoustic stimulation at 1, 3, 10, and 15 Hz) every 15 min was studied in freely moving cats. The repeated administration of naloxone provoked some behavioral manifestations that resemble those produced by electrical amygdaloid kindling. Photoacoustic stimulation accentuated the manifestations. All the animals presented generalized behavioral seizures when total naloxone administration reached 80 mg/kg. None of the animals demonstrated postictal depression. These results suggest an inhibitory role of endogenous opioids and/or GABA in epileptogenesis.