Changes in TRPV1-Mediated Physiological Function in Rats Systemically Treated With Capsaicin on the Neonate

Abstract

Capsaicin is the active component of chili peppers and is a hydrophobic, colorless, odorless, and crystalline to waxy compound. The transient receptor potential vanilloid 1 (TRPV1) is the capsaicin receptor channels that are involved in a variety of functions like transduction and transmission of the physiological stimulus. Subcutaneous injection of capsaicin to a newborn rat leads to involuntary lifelong TRPV1 desensitization. Various physiological changes including sensory and homeostatic actions in the body associated with neonatal capsaicin treatment are induced by direct TRPV1 channel targeting. Interesting changes include unique phenomena such as the reduction in pain perception, abnormal body temperature, increase in infection, infectious or neuropathological itching, and irregular circadian core body temperature rhythm. These symptoms are associated with relatively higher fever or loss of sensory c-fiber related to TRPV1 desensitization. The aforementioned outcomes not only provide a warning about the risk of capsaicin exposure in newborns but also indicate the possible occurrence of relatively rare diseases that are difficult to diagnose. Therefore, Therefore, the present review aims to summarize the unique phenomena caused by systemic capsaicin administration in neonatal rats.

Calcium Entry through TRPV1: A Potential Target for the Regulation of Proliferation and Apoptosis in Cancerous and Healthy Cells

“…While these channels generally exhibit selectivity for Ca 2+ over Na + , the precise nature of this selectivity depends on a variety of factors, including the nature and concentration of the agonist [26]. TRPV1 is involved in thermoregulation, circadian rhythms, energy intake and metabolism, and acute, chronic, and inflammatory nociception; as such, the ion channel receptor is a target in the development of analgesic therapies [27][28][29][30][31][32]. Furthermore, given its role in modulating [Ca 2+ ] i , TRPV1 influences the balance between proliferation and apoptosis [33].…”

Transient receptor potential vanilloid 1 interacts with Toll-like receptor 4 (TLR4)/cluster of differentiation 14 (CD14) signaling pathway in lipopolysaccharide-mediated inflammation in macrophages

“…The function of the TRPV1 receptor is well-established in the somatosensory system and is highly associated with the activation of inflammatory pain signaling [ 10 , 11 ]. Emerging evidence suggests the involvement of the TRPV1 receptor in LPS-induced inflammation; however, its underlying regulatory mechanisms are not fully understood.…”

“…The transient receptor potential vanilloid 1 (TRPV1), also known as the capsaicin receptor, is a nonselective cation channel with a high permeability of Ca 2+ [ 10 , 11 , 12 ]. The TRPV1 receptor widely expresses primary sensory neurons, sensory C- and A-fibers, and mediates various physiological functions of neurons [ 11 , 12 ]. TRPV1 receptor can be activated by multiple biological stimuli, including heat, capsaicin, protons, and clinical drugs [ 13 , 14 , 15 , 16 ].…”

Capsaicin: A Novel Approach to the Treatment of Functional Dyspepsia

“…[ 66 ] The destruction of 80–95% of afferent C‐fiber in the lumbar dorsal roots and permanent insensitivity of the TRPV1 receptor was observed after subcutaneous injection of CAP into newborn rats. [ 67 ] Various studies have investigated the pain response in CAP‐treated newborn rats. Due to the destruction of the nociceptive fiber, neonatal CAP‐treated rats have a higher threshold to thermal, mechanical, and chemical stimuli.…”