Taste the Pain: The Role of TRP Channels in Pain and Taste Perception

Abstract

Transient receptor potential (TRP) channels are a superfamily of cation transmembrane proteins that are expressed in many tissues and respond to many sensory stimuli. TRP channels play a role in sensory signaling for taste, thermosensation, mechanosensation, and nociception. Activation of TRP channels (e.g., TRPM5) in taste receptors by food/chemicals (e.g., capsaicin) is essential in the acquisition of nutrients, which fuel metabolism, growth, and development. Pain signals from these nociceptors are essential for harm avoidance. Dysfunctional TRP channels have been associated with neuropathic pain, inflammation, and reduced ability to detect taste stimuli. Humans have long recognized the relationship between taste and pain. However, the mechanisms and relationship among these taste-pain sensorial experiences are not fully understood. This article provides a narrative review of literature examining the role of TRP channels on taste and pain perception. Genomic variability in the TRPV1 gene has been associated with alterations in various pain conditions. Moreover, polymorphisms of the TRPV1 gene have been associated with alterations in salty taste sensitivity and salt preference. Studies of genetic variations in TRP genes or modulation of TRP pathways may increase our understanding of the shared biological mediators of pain and taste, leading to therapeutic interventions to treat many diseases.

Keywords: TRP channel; capsaicin; genomics; pain; taste; transient receptor potential.

Figure 1

Role of transient receptor potentials (TRPs) in taste and pain sensation: (A) TRPs involved in pain and taste perception; (B) afferent inputs from nociceptors enter the central nervous system (CNS) via the dorsal root ganglion (DRG) and trigeminal ganglion (TG) for transmission to the cerebral cortex for interpretation. TRPA = transient receptor potential ankyrin; TRPM = transient receptor potential melastatin; TRPV = transient receptor potential vanilloid; TRPC = transient receptor potential-canonical; DRG = dorsal root ganglion; NTS = nucleus tractus solitarius. The blue and purple lines correspond to cranial nerves VII and IX.