Modulation of Motoneuron Excitability by Brain-Derived Neurotrophic Factor.
Gonzalez, Michael and William F. Collins, III.
Department of Neurobiology and Behavior, SUNY at Stony Brook, Stony Brook,
New York 11794-5230.
APStracts 3:0218N, 1996.
The influence of neurotrophins on motoneuron survival and development has been
well documented in cell cultures and neonates. In the present study, the role
of BDNF in the maintenance of motoneuron electrical properties was
investigated. In adult male rats, BDNF- or saline-saturated gelfoam was
inserted between the medial and lateral heads of the gastrocnemius muscles.
After 5 days survival, in vivo intracellular recordings were obtained, and
motoneuron biophysical properties were measured. In BDNF-treated rats,
significant decreases in mean rheobase and in total cell capacitance of medial
gastrocnemius motoneurons were observed. In addition, a concommitant increase
in input resistance and decrease in membrane time constant were noted in BDNF
treated rats but were not statistically significant. No significant treatment
effect was observed in motoneuron conduction velocity, action potential
amplitude, equalizing time constant, electrotonic length, after-
hyperpolarization amplitude and duration, and membrane potential sag during
current injection. The observed changes in motoneuron rheobase and total cell
capacitance suggest that application of BDNF produces an increase in
motoneuron excitability coincident with a reduction in size. These data are
discussed with respect to the possible role of BDNF as a muscle-derived
trophic factor for the regulation of motoneuron excitability.
Received 14 June 1996; accepted in final form 18 September 1996.
APS Manuscript Number J475-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 November 1996