Spinal sensory innervation of the intestine.

Sensing our internal environment, or interoception, is essential under physiologic circumstances, such as controlling food intake, and under pathophysiologic circumstances, often triggering abdominal pain. The sensory neurons that innervate the gastrointestinal (GI) tract to mediate interoception originate in two separate parts of the peripheral nervous system: the spinal sensory neurons, whose cell bodies reside in the dorsal root ganglia (DRG), and the vagal sensory neurons, whose cell bodies reside in the nodose ganglia. While the vagal sensory neurons have been extensively studied for their roles in interoception, the roles of the DRG sensory neurons in internal gut sensing are only beginning to be uncovered. Here, we review the recent advances in understanding the diverse properties and functions of gut-innervating DRG sensory neurons and highlight the many unknowns with regards to this understudied population in regulating interoception.