Time course of transient expression of GDNF protein in rat granule cells of the bilateral dentate gyri after unilateral intrahippocampal kainic acid injection

We examined the time course of expression of glial cell line-derived neurot rophic factor (GDNF) protein in the granule cells of the dentate gyrus foll owing unilateral intrahippocampal injection of kainic acid (KA). Recurrent behavioral seizures were observed approximately 1 h after KA injection, whi ch lasted for 4-6 h. GDNF immunoreactivity began to increase bilaterally in the granule cells within 3 h after KA injection, continued to increase unt il post-injection day (PID) 4, and returned to the control level by PID 7. The results suggest that the increase of GDNF protein in the granule cells may be ascribable to seizures induced by the KA injection. The increase of GDNF protein might promote survival of the granule cells after the intrahip pocampal KA injection. (C) 1999 Published by Elsevier Science Ireland Ltd. Alt rights reserved.