Table 2.

Threshold intravenous doses of PTZ for first twitch and clonic and tonic seizure activity^a

Genotype	First twitch (mmol/kg)	Clonus (mmol/kg)	Tonus (mmol/kg)
Wild-type	0.361 ± 0.017	0.460 ± 0.022	0.471 ± 0.022
GluK1−/−	0.409 ± 0.031	0.459 ± 0.028	0.526 ± 0.047
GluK2−/−	0.314 ± 0.019	0.442 ± 0.028	0.835 ± 0.043*

^aPTZ at a concentration of 10 mg/ml (72.4 mm) was infused intravenously at a rate of 0.05 ml/min. Cumulative doses to elicit first twitch and clonic and tonic seizures were determined from the time after onset of the infusion, as described in Materials and Methods. Each group consisted of 8 mice. Values are mean ± SEM of the threshold for each of the behavioral signs. Mean values in the GluK1^−/− and GluK2^−/− groups were not significantly different from the corresponding values in the wild-type groups, except as indicated.

*p < 0.001, compared with wild-type group (one-way ANOVA and Tukey's HSD test).