REPEATED ELECTROCONVULSIVE SHOCK EXTENDS THE DURATION OF ENHANCED GENE-EXPRESSION FOR BDNF IN RAT-BRAIN COMPARED WITH A SINGLE ADMINISTRATION

Brain-derived neurotrophic factor (BDNF) is known to modulate synaptic function as well as to promote neuronal growth in the adult brain. Th e aim of the present study was to compare the duration of electroconvu lsive shock (ECS)-induced BDNF gene expression following a single shoc k (acute ECS) to the more clinically relevant situation, where repeale d shocks (chronic ECS) are administered. For this purpose, we have use d quantitative in situ hybridisation with a S-35-labelled oligonucleot ide probe complementary to mRNAs encoding genes for all forms of BDNF. The results confirm previous studies that the administration of ECS i ncreases BDNF mRNA abundance in parts of rat brain with particularly m arked changes in the granule cell layer of the dentate gyrus, We also for the first time show the long lasting nature of the increase in BDN F mRNA abundance measured after chronic ECS, i.e., significant increas es in BDNF mRNA persisted up to 48 h after the last shock. Acute ECS a t 6 h after the shock produced a slightly more pronounced effect on BD NF mRNA abundance than chronic ECS 6 h after the last shock. However, this change was not delectable already 24 h after a single ECS. These results indicate that repeated ECS induces adaptive changes in BDNF mR NA expression. (C) 1998 Elsevier Science B.V. All rights reserved.