Dorsal root ganglion - a potential new therapeutic target for neuropathic pain

Abstract

A regional approach can protect our patients from often unacceptable adverse effects produced by systematically applied drugs. Regional therapeutic approaches, as well as interventions at the level of the peripheral nervous system and particularly the dorsal root ganglion (DRG), represent an alternative to the systemic application of therapeutic agents. This article provides an overview of DRG anatomical peculiarities, explains why the DRG is an important therapeutic target, and how animal models of targeted drug delivery can help us in the translation of basic research into clinical practice.

Keywords: dorsal root ganglion; neuropathic pain; pain therapy; targeted drug delivery.

Figure 1

The position of the rat L5 DRG and its relation with surrounding bone structures and cauda equina. Abbreviations: DRG, dorsal root ganglion; DR, dorsal root; CE, cauda equina; P, pedicles.

Figure 2

Schematic drawings (A and B) and photo (C) of rat spine depicting position of dorsal root ganglia and surgical approach used for DRG injection. Reliably precise injection can be performed using minimal laminectomy, while blind needle-insertion approach requires a lot of skill and experience. The dorsal root ganglion is covered by laminar bone. (B) Removal of laminar bone superior to the foramen and the L4 accessory process reveals the distal dorsal root ganglion, recognized by its broader diameter. Abbreviations: red arrows, dorsal root ganglion (L5 and L6); sap, superior articular processes; sp, spinous processes; tp, transverse processes; lam, laminar bone.

Figure 3

Microphotograph of dorsal root ganglion obtained from frozen section showing juxtaposition of DRG neurons and satellite cells. Abbreviations: SC, satellite cells; N, neurons; Nu, nucleolus; BV, blood vessels; NC, nucleus; CT, connective tissue.