Tectal graft modulation of audiogenic seizures in long-evans rat

Audiogenic seizure (AGS) activity can be induced in the seizure-resistant L ong-Evans rat by postnatal priming. This study examined the effects of unil ateral lesions of the inferior colliculus (IC) and implantation of tectal g rafts on AGS components. Animals were primed with a 10-kHz tone burst at 12 0 dB on postnatal day 14 and tested for AGS susceptibility on day 28, and t hen two groups were unilaterally lesioned including animals receiving embry onic day 16-17 grafts of caudal tectum. Subsequently, animals were repeated ly tested for wild running and clonic-tonic convulsion components of AGS. T he results demonstrate that unilaterally grafted animals with partial IC le sions showed significant reduction in the incidence of clonus expression wi th greater terminal uniphasic wild running behavior. These effects were str onger than in animals with comparable unilateral lesions alone. Many neuron s in graft cases were in direct contact with host tissues to provide a subs trate for tissue interactions previously demonstrated to promote neuron sur vival and remediate IC functions. (C) 2000 Academic Press.