Tonically Active αGABA Receptors Reduce Motoneuron Excitability and Decrease the Monosynaptic Reflex.

Motoneurons, the final common path of the Central Nervous System (CNS), are under a complex control of its excitability in order to precisely translate the interneuronal pattern of activity into skeletal muscle contraction and relaxation. To fulfill this relevant function, motoneurons are provided with a vast repertoire of receptors and channels, including the extrasynaptic GABA receptors which have been poorly investigated. Here, we confirmed that extrasynaptic α5 subunit-containing GABA receptors localize with choline acetyltransferase (ChAT) positive cells, suggesting that these receptors are expressed in turtle motoneurons as previously reported in rodents.