Pentylenetetrazol augmentation of developing kindled amygdaloid seizures

The effects of daily administration of pentylenetetrazol (PTZ) on the rate of the development of kindled amygdaloid seizures (KAS) were tested in the rat. Rats were pretreated for 6 days with 25 mg/kg PTZ or normal saline 15 min. prior to each daily amygdaloid stimulation. The PTZ group exhibited fully developed KAS, including a maximal behavioral ranking (BR) and an afterdischarge duration (AD) of over 90 sec, in 3.8 ± 0.3 stimulations compared to 8.0 ± 0.6 stimulations (ave. ± SEM) for the saline controls. Within 10 min after dosing, PTZ consistently induced intermittent spiking of 5 sec or less in the EEG and behaviorally induced head nodding and sniffing. However, chemical kindling due to the 6 repetitive doses of PTZ was not observed. When the PTZ pretreatment was stopped on the 7th day, the BR and AD of the PTZ pretreatment group decreased from 187% and 161% of control values, respectively, to 118% and 100% of control. It appears that PTZ augments both the AD and BR of the developing KAS but does not accelerate the actual rate of the development of the KAS.