Fig. 4.

Distribution of sodium channels on afferents, relative to α₅GABA_A receptors. A: large dorsal column branch of a proprioceptive Ia afferent (horizontal, top) branching to primary collateral (1°) that descended into the gray matter and formed a secondary branch (2°). Afferent labeled with neurobiotin (green). The sodium channels labeled with a pan-sodium antibody and colocalized on the afferent are indicated in white (by white arrows, channels outside afferent not shown). Sodium channel immunolabelling occurred in clusters at branch point nodes and at other nodes on long unbranched sections of the afferent. Sodium α₅GABA_A receptor clusters on the afferent (yellow arrows) were expressed near the sodium channel nodes (receptors outside node red). Nodes expanded in box insets. NF200, purple. B: branch points in primary and secondary collateral with sodium channel clusters in cutaneous afferent. Terminal branches (3°) and boutons typically lacked sodium channels, with a few exceptions in long or complex terminal branches (white arrows). Terminals lacking GABA receptors are marked with green arrows.