Abstract
Recently detection of c-fos induction after external stimulation has been widely performed for functional mapping. In this study we examined the induction of c-fos mRNA after systemic administration of a chemical convulsant, pentylenetetrazole (PTZ), in four brain areas of the developing rat.
Subcutaneous injection of PTZ (50mg/kg) induced occasional brief myoclonic jerk from postnatal day 8 to day 49, and significantly enhanced c-fos mRNA expression in the neocortex at postnatal day 8, 23 and 49, compared with saline administration. The level of c-fos mRNA expression in the PTZ-injected animals increased progressively from day 8 to 23 and markedly from day 23 to 49. In the piriform cortex, a PTZ-induced increase in the proto-oncogene expression was observed only at day 49 postpartum. In contrast, the levels of c-fos mRNA were unchanged after administration of the convulsant in the hippocampus and the striatum throughout day 8 to 49.
The regional variation in the development of PTZ-induced c-fos mRNA expression might parallel a change in the size or distribution of neuronal populations involved in induction of the phenotypically identical seizure. Alternatively, it might reflect an alteration in the neural circuitry associated with such long-lasting effects of epileptic seizure as kindling phenomenon.
