FIG. 9.
Major transmitters (labeled in presynaptic terminals), presynaptic (red boxes) and postsynaptic (yellow boxes) receptors, and ion channel effectors involved in conveying main excitatory/inhibitory synaptic drive and modulatory input to motoneurons. Transmitter systems converge on 3 major effectors: ICa HVA, Ih, and IK leak-ICAT. Although graphically separated, several of the listed transmitters are colocalized in synaptic boutons. (P)?, possibility that phosphorylation of receptors or associated synaptic proteins play a role in regulating motoneuronal excitability; Glu, glutamate; Gly, glycine; AVP, arginine vasopressin.