PT  - JOURNAL ARTICLE
AU  - G.S. Bhumbra
AU  - M. Beato
TI  - Recurrent excitation between motoneurones propagates across segments and is purely glutamatergic
AID  - 10.1101/160150
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 160150
4099  - http://biorxiv.org/content/early/2017/07/06/160150.short
4100  - http://biorxiv.org/content/early/2017/07/06/160150.full
AB  - Spinal motoneurones constitute the final output for the execution of motor tasks. In addition to innervating muscles, motoneurones project excitatory collateral connections to Renshaw cells and other motoneurones, but the latter have received little attention. We show that motoneurones receive strong synaptic input from other motoneurones throughout development and into maturity with fast type motoneurones systematically receiving greater recurrent excitation than slow type motoneurones. Optical recordings show that activation of motoneurones in one spinal segment can propagate to adjacent segments even in the presence of intact recurrent inhibition. Quite remarkably, while it is known that transmission at the neuromuscular junction is purely cholinergic and Renshaw cells are excited through both acetylcholine and glutamate receptors, here we show that neurotransmission between motoneurones is purely glutamatergic indicating that motoneurones differentiate their transmission system depending on their post-synaptic target.