Serotonergic mechanism in seizures kindled from the rabbit amygdala.

The effect of agents enhancing or diminishing serotonergic activity on seizures kindled from the rabbit amygdala was examined. Acute administration of 5-hydroxytryptophan (5-HTP) 10 and 25 mg/kg (administered in combination with a peripheral decarboxylase inhibitor), quipazine 1, 5 and 10 mg/kg or femoxetine 5 and 15 mg/kg which enhance serotonergic activity affected neither the intensity of behavioral seizures nor the duration of bioelectrical ones. 5-HTP 25 mg/kg and femoxetine 15 mg/kg prolonged the duration of behavioral seizures. Chronic administration of 5-HTP 25 mg/kg and femoxetine 15 mg/kg prolonged the duration of behavioral seizures. Chronic administration of 5-HTP 25 mg/kg had no effect on the development of kindled seizures. Acute administration of p-chlorphenylalanine (PCPA) 250 mg/kg reduced the intensity and shortened the duration of behavioral seizures. Cyproheptadine which blocks the postsynaptic action of serotonin shortened the duration of behavioral seizures. Chronic administration of PCPA 80 mg/kg delayed the development of kindled seizures. It is concluded that a pharmacological stimulation of the serotonergic system exerts no or little enhancing effect, whereas pharmacological inhibition of this system attenuates and delays the development of seizures kindled from the rabbit amygdala.