Kim_2010_Neurotoxicol.Teratol_32_551

Seizures have been reported to modify neural development in the immature brain. In this study, we attempted to determine whether pentylenetetrazol (a GABAergic receptor antagonist, PTZ)-induced seizures influence cell proliferation in zebrafish larvae (5 and 15 days of post-fertilization), using bromodeoxyuridine (BrdU) to label dividing cells. In the brains of 5 dpf larvae, PTZ treatment significantly reduced the number of BrdU-labeled cells in the telencephalic area (pallium and subpallium), diencephalic area (thalamus and preoptic area), medial tectal proliferation zone, and medial cerebellar proliferation zone to 52.4%, 62.9%, 47.2%, and 54.0% of the controls, respectively. In contrast, we noted no reductions in the number of BrdU-labeled cells in the brains of the 15 dpf larvae. The double-label of BrdU and Hu, a neuronal marker, demonstrated that the majority of newborn cells showed the neuronal phenotype. Similarly, kainic acid (200 microM), a glutamatergic receptor agonist, significantly reduced the number of BrdU-labeled cells in the telencephalic area, diencephalic area, and medial tectal proliferation zone to 51.4%, 61.9%, and 40.4% of the controls, respectively. Physostigmine (500 microM), an acetylcholinesterase inhibitor, also reduced the number of BrdU-labeled cells in the telencephalic area, diencephalic area, medial tectal proliferation zone, and medial cerebellar proliferation zone to 52.8%, 35.9%, 30.5%, and 39.8% of the controls, respectively. All of these drugs resulted in electrographic seizures in the larval brain when perfused directly through artificial cerebrospinal fluid. These results indicated that seizures result in a massive reduction in cell proliferation in wide-ranging areas of the developing brain.