Figure 1. Increased susceptibility to and mortality from pilocarpine-induced seizures in Lmx1b^f/f/p mice.

A, mean maximum Racine grade achieved after each cumulative pilocarpine dose in male (squares) and female (circles) Lmx1b^f/f (solid symbols) and Lmx1b^f/f/p (open symbols) mice; n = 8 for each group. *P < 0.05 between genotype among sexes and between sexes among genotype; †P < 0.05 between sexes for Lmx1b^f/f/p mice; #P < 0.05 between genotypes for females; ‡P < 0.05 between sexes for Lmx1b^f/f mice. B, latency to achieve each Racine grade in male and female Lmx1b^f/f and Lmx1b^f/f/p mice. Latencies were determined from the time of the first pilocarpine injection to the time of first appearance of behaviour consistent with each Racine grade. Error bars, ± SEM; *P < 0.001 between genotypes among sexes and between sexes among genotype. C, interval from the time of onset of one Racine grade to the next in male and female Lmx1b^f/f and Lmx1b^f/f/p mice. Note that the absence of 5-HT neurones causes a decrease in latency to Racine grade 1–3 seizures, but has no effect on progression to generalised seizures (grades 4 and 5); n = 8 for each group. Mean ± SEM are given. *P < 0.001 between genotype among sexes and between sexes among genotype. D, Kaplan–Meier survival curves depicting percentage of male (dotted lines) and female (continuous lines) Lmx1b^f/f (black) and Lmx1b^f/f/p (grey) mice still alive after each cumulative pilocarpine dose. Log rank P-value = 0.007 for genotype and sex; n = 8 for each group.