Table 5.

Kindling parameters and effect of valproate in good and poor valproate responders

Parameter	Poor responders	Good responders	p
Kindling development
Initial ADT (μA)	190.6 ± 28.6 (110–590)	159.1 ± 23.3 (90–330)	0.2384
Kindling rate (number of stimulations until stage V)	7.4 ± 0.5 (5–12)	7.7 ± 0.9 (5–12)	0.8011
Cumulative afterdischarge duration until stage V (sec)	151.9 ± 12.2 (52–250)	210.1 ± 28.3 (110–385)	0.1747
Effect of VPA on ADTs in kindled rats
Control ADT (μA) in fully kindled rats	83.3 ± 8.3 (39–145)	55.8 ± 6.7 (29–110)*	0.0246
VPA ADT (% of individual control ADT)	123.3 ± 16.2 (25–233)	394.8 ± 34.5 (245–640)***	<0.0001
VPA plasma level (μg/ml)	383.7 ± 10.0 (320–461)	380.5 ± 14.9 (303–441)	0.7860

For comparison of kindling development and the effect of VPA on ADTs, the group of 27 kindled rats was divided into poor responders (individual ADT increase after 200 mg/kg VPA, i.p., below mean group increase of ADT of 234%; n = 16) and good responders (individual ADT increase >234%; n = 11). Good and poor responders did not differ in kindling development (Mann–Whitney U test). Good and poor responders significantly differed in the predrug (control) ADT determined after injection of saline and in the effect of VPA on ADTs (Student's t test; marked by asterisks). The average VPA concentration was about the same in good and poor responders (Mann–Whitney U test). Data are means ± SEM (range).