Sensory Blurring in Nociplastic Pain: The Role of Descending Inhibitory Dysfunction and Gut–Brain Axis Alterations in Older Adults

Background: Inhibitory processes in the nervous system are traditionally conceptualized as suppressive mechanisms; however, their fundamental role is the refinement and optimization of sensory information. In nociception, this function is mediated by the descending pain inhibitory system (DPIS), which modulates nociceptive transmission at multiple hierarchical levels. Biological sex and gender-related factors significantly influence these inhibitory pathways, yet they are often overlooked in clinical frameworks. Methods: A narrative review was conducted using PubMed, MEDLINE, and Scopus databases, focusing on studies published between 2010 and 2025. Search terms included “descending pain inhibitory system,” “nociplastic pain,” “aging,” “sex differences,” “gender,” and “gut–brain axis.” Approximately 30 key references were synthesized. Results: The DPIS enhances the precision of nociceptive signals through mechanisms analogous to lateral inhibition. In chronic and nociplastic pain, this refinement process is impaired, leading to “sensory blurring.” Aging exacerbates these changes through neurochemical depletion and neuroinflammation. Crucially, this decline follows sex-specific trajectories; estrogen depletion in post-menopausal females accelerates the loss of monoaminergic inhibitory reserves, while gender-related sociocultural stressors can further disrupt top-down executive control. Additionally, alterations in the gut–brain axis signaling—modulated by sex-specific gut microbiota profiles—further disrupt inhibitory control. Conclusions: Chronic pain may be conceptualized as a disorder of sensory refinement rather than excessive nociceptive input. Inclusion of sex and gender as biological variables is essential for precision pain management. Therapeutic strategies should focus on restoring inhibitory precision through both central and systemic approaches, tailored to the patient’s hormonal and physiological profile.