The dorsal root ganglion T-junction: a critical node in somatosensory processing and pain pathogenesis.

Pseudounipolar neurons in the dorsal root ganglia (DRG), as the central nodes of primary sensory afferents, possess a distinctive T-junction that is not merely a morphological peculiarity but also performs complex roles in rapid, multiplexed shunting and regulation of sensory signals. This specialized geometry enables separation, filtering, and feedback regulation of neuronal signals, thereby coordinating peripheral and central responses at multiple levels. Recent advances, including spatial transcriptomics, single-cell sequencing, super-resolution microscopy, organoid models, and novel electrophysiological methods, have permitted more precise dissection of the T-junction's molecular composition, ion-channel distribution, and electrophysiological properties. Here, we review current knowledge of the T-junction's developmental regulation and multilayered molecular networks, and we detail its functional alterations in both physiological signaling and pathological pain states, with particular emphasis on ion-channel modulation, signal attenuation, and selective transmission mechanisms. Finally, we discuss contemporary pain-intervention approaches and prospects for precision-targeted therapies, aiming to provide a theoretical foundation for future studies in pain physiology and clinical translation.