Renal interoception: form, function, and open questions

The kidneys filter the blood and balance fluid and electrolytes to keep the composition of the internal environment within the narrow parameters essential for life. A perturbation to the internal state, such as a sudden loss of blood or dehydration, engages autonomic efferent and neuroendocrine pathways to adjust kidney function rapidly and robustly. The mechanisms of these multiorgan pathways are extensively studied. By contrast, the roles of sensory afferent nerves in regulating renal function are just beginning to be understood. In this review, we examine recent advances in understanding the morphology, identity, and functions of the renal sensory nerves that form the first node in the interoceptive pathways that update the kidney on its own internal state. We end by highlighting open questions in the field, influenced by recent work in other areas of interoception neuroscience, and the outstanding gaps in our knowledge of kidney biology.