Brain-Derived Neurotrophic Factor Blocks Long-Term Depression in Rat Visual Cortex. Akaneya, Yukio, Tadaharu Tsumoto and Hiroshi Hatanaka. Department of Neurophysiology, Biomedical Research Center, Osaka University Medical School, Yamadaoka, Suita City, 565 Japan and Division of Protein Biosynthesis, Institute for Protein Research, Osaka Universty, Suita City, 565 Japan.
APStracts 3:0185N, 1996.
SUMMARY AND CONCLUSIONS
1. Brain-derived neurotrophic factor (BDNF) has been reported to play a role in long-term potentiation (LTP) in hippocampus, but whether it is involved also in long-term depression (LTD) is not yet known. In this study, we tested whether BDNF and its gene family, nerve growth factor (NGF), have any effect on synaptic transmission and LTD in visual cortical slices of young rats. 2. An application of BDNF at the concentration of 20 ng/ml did not significantly change layer II/III field responses evoked by layer IV stimulation at 0.1 Hz, although at 200 ng/ml it enhanced responses. BDNF at 20 ng/ml prevented LTD of field responses from being induced by low-frequency stimulation (1 Hz for 15 min) of layer IV. NGF did not have such effects in the same concentration range as that of BDNF. 3. The action of BDNF was antagonized by K252a, an inhibitor of receptor tyrosine kinases. When K252a alone was applied to slices, LTD of stronger magnitude than in control slices was induced by low- frequency stimulation. 4. These results suggest that endogeneous BDNF may prevent synapses from being depressed by low-frequency inputs in the developing visual cortex.

Received 27 June 1996; accepted in final form 5 September 1996.
APS Manuscript Number J508-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 7 October 1996