scholarly journals Diurnal Variation in Trigeminal Pain Sensitivity in Mice

2021 ◽  
Vol 15 ◽  
Author(s):  
Ayako Niiro ◽  
Sachi N. Ohno ◽  
Kanae A. Yamagata ◽  
Kazuaki Yamagata ◽  
Kazuo Tomita ◽  
...  

Management of time and circadian disruption is an extremely important factor in basic research on pain and analgesia. Although pain is known to vary throughout the day, the mechanism underlying this circadian variation remains largely unknown. In this study, we hypothesized that the process of pain transmission to the central nervous system (after receiving nociceptive stimuli from outside the body) would show day-night differences. Ten-week-old male mice were kept under a strict 12/12-h light/dark cycle for at least 10 days. Formalin was then injected into the second branch region of the trigeminal nerve and the duration of pain-related behaviors (PRBs) was assessed. Immunohistochemical staining was then performed, and the c-Fos-immunopositive cells in the trigeminal spinal tract subnucleus caudalis (Sp5C) were counted. The results showed that the duration of PRBs was longer and the number of c-Fos immunopositive cells in the Sp5C was higher at nighttime than during the day. In addition, the trigeminal ganglia (TG) were extracted from the mice and examined by quantitative real-time PCR to evaluate the daytime and nighttime expression of nociceptive receptors. The results showed that the mRNA expression of transient receptor potential ankyrin 1 in the TG was significantly higher at night than during the day. These results suggest that pain in the trigeminal nerve region is more intense at nighttime, when rodents are active, than during the daytime, partly due to differences in nociceptor expression.

2019 ◽  
Vol 20 (6) ◽  
pp. 1380 ◽  
Author(s):  
Erik Behringer ◽  
Md Hakim

Effective delivery of oxygen and essential nutrients to vital organs and tissues throughout the body requires adequate blood flow supplied through resistance vessels. The intimate relationship between intracellular calcium ([Ca2+]i) and regulation of membrane potential (Vm) is indispensable for maintaining blood flow regulation. In particular, Ca2+-activated K+ (KCa) channels were ascertained as transducers of elevated [Ca2+]i signals into hyperpolarization of Vm as a pathway for decreasing vascular resistance, thereby enhancing blood flow. Recent evidence also supports the reverse role for KCa channels, in which they facilitate Ca2+ influx into the cell interior through open non-selective cation (e.g., transient receptor potential; TRP) channels in accord with robust electrical (hyperpolarization) and concentration (~20,000-fold) transmembrane gradients for Ca2+. Such an arrangement supports a feed-forward activation of Vm hyperpolarization while potentially boosting production of nitric oxide. Furthermore, in vascular types expressing TRP channels but deficient in functional KCa channels (e.g., collecting lymphatic endothelium), there are profound alterations such as downstream depolarizing ionic fluxes and the absence of dynamic hyperpolarizing events. Altogether, this review is a refined set of evidence-based perspectives focused on the role of the endothelial KCa and TRP channels throughout multiple experimental animal models and vascular types. We discuss the diverse interactions among KCa and TRP channels to integrate Ca2+, oxidative, and electrical signaling in the context of cardiovascular physiology and pathology. Building from a foundation of cellular biophysical data throughout a wide and diverse compilation of significant discoveries, a translational narrative is provided for readers toward the treatment and prevention of chronic, age-related cardiovascular disease.


Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1401
Author(s):  
Katharina E. M. Hellenthal ◽  
Laura Brabenec ◽  
Eric R. Gross ◽  
Nana-Maria Wagner

The transient receptor potential (TRP) cation channel superfamily comprises more than 50 channels that play crucial roles in physiological processes. TRP channels are responsive to several exogenous and endogenous biomolecules, with aldehydes emerging as a TRP channel trigger contributing to a cellular cascade that can lead to disease pathophysiology. The body is not only exposed to exogenous aldehydes via tobacco products or alcoholic beverages, but also to endogenous aldehydes triggered by lipid peroxidation. In response to lipid peroxidation from inflammation or organ injury, polyunsaturated fatty acids undergo lipid peroxidation to aldehydes, such as 4-hydroxynonenal. Reactive aldehydes activate TRP channels via aldehyde-induced protein adducts, leading to the release of pro-inflammatory mediators driving the pathophysiology caused by cellular injury, including inflammatory pain and organ reperfusion injury. Recent studies have outlined how aldehyde dehydrogenase 2 protects against aldehyde toxicity through the clearance of toxic aldehydes, indicating that targeting the endogenous aldehyde metabolism may represent a novel treatment strategy. An addition approach can involve targeting specific TRP channel regions to limit the triggering of a cellular cascade induced by aldehydes. In this review, we provide a comprehensive summary of aldehydes, TRP channels, and their interactions, as well as their role in pathological conditions and the different therapeutical treatment options.


2020 ◽  
Vol 21 (21) ◽  
pp. 7942 ◽  
Author(s):  
Linda Rankin ◽  
Christopher J. Fowler

Palmitoylethanolamide (PEA, N-hexadecanoylethanolamide) is an endogenous compound belonging to the family of N-acylethanolamines. PEA has anti-inflammatory and analgesic properties and is very well tolerated in humans. In the present article, the basal pharmacology of PEA is reviewed. In terms of its pharmacokinetic properties, most work has been undertaken upon designing formulations for its absorption and upon characterising the enzymes involved in its metabolism, but little is known about its bioavailability, tissue distribution, and excretion pathways. PEA exerts most of its biological effects in the body secondary to the activation of peroxisome proliferator-activated receptor-α (PPAR-α), but PPAR-α-independent pathways involving other receptors (Transient Receptor Potential Vanilloid 1 (TRPV1), GPR55) have also been identified. Given the potential clinical utility of PEA, not least for the treatment of pain where there is a clear need for new well-tolerated drugs, we conclude that the gaps in our knowledge, in particular those relating to the pharmacokinetic properties of the compound, need to be filled.


2007 ◽  
Vol 35 (1) ◽  
pp. 115-119 ◽  
Author(s):  
J.P.H. Schoeber ◽  
J.G.J. Hoenderop ◽  
R.J.M. Bindels

Ca2+ is an essential ion in all organisms and many physiological functions in the body rely on the exact maintenance of the Ca2+ balance. The epithelial Ca2+ channels TRPV5 [TRP (transient receptor potential) vanilloid 5] and TRPV6 are the most Ca2+-selective members of the TRP superfamily and are generally considered as the gatekeepers of Ca2+ entry across epithelia. TRPV5 is involved in Ca2+ reabsorption from pro-urine, while TRPV6 has an essential role in intestinal Ca2+ uptake. These channels are the prime targets of calciotropic hormonal regulation, including vitamin D and parathyroid hormone. In addition, extra- and intra-cellular signalling by associated proteins and Ca2+ itself play key roles in TRPV5 and TRPV6 regulation. In this paper, we describe the present understanding of the concerted action of calbindin-D28k, klotho and BSPRY (B-box and SPRY-domain-containing protein) at different levels throughout the epithelial cell to control Ca2+ influx at the luminal entry gate.


2022 ◽  
Vol 2022 ◽  
pp. 1-7
Author(s):  
Chuanying Li ◽  
Rong Cheng ◽  
Lin Li ◽  
Miaomiao Chen ◽  
Cheng Wu

Duodenal ulcer seriously affects the quality of life and life safety of children, but the pathogenesis of children with duodenal ulcer is still unclear. As an important second messenger in the body, Ca2+ participates in the physiological and pathological processes of various diseases. Therefore, transient receptor potential vanilloid type 4 (TRPV4) as one of the channels that mediate Ca2+ has attracted widespread attention in recent years. Here, we found that TRPV4 is highly expressed in children with duodenal ulcer and has good diagnostic value through specimens of children with duodenal ulcer, and animal experiments have proved that TRPV4 is also highly expressed in duodenal ulcer mice. In addition, TRPV4 can enhance intestinal permeability, thereby promoting further infiltration of inflammatory factors. In summary, these results indicate that TRPV4 is involved in the occurrence and development of duodenal ulcer. Therefore, this study provides the diagnostic and therapeutic value of TRPV4 in children with duodenal ulcer.


Pharmaceutics ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 669
Author(s):  
Francesca Maestrelli ◽  
Elisa Landucci ◽  
Enrico De Luca ◽  
Giulia Nerli ◽  
Maria Camilla Bergonzi ◽  
...  

The transient receptor potential akyrin type-1 (TRPA1) is a non-selective cation channel playing a pivotal role in pain sensation and neurogenic inflammation. TRPA1 channels expressed in the central nervous system (CNS) have a critical role in the modulation of cortical spreading depression (CSD), which is a key pathophysiological basis of migraine pain. ADM_09 is a recently developed lipoic acid-based TRPA1 antagonist that is able to revert oxaliplatin-induced neuropathic pain and inflammatory trigeminal allodynia. In this context, aiming at developing drugs that are able to target TRPA1 channels in the CNS and promote an antioxidant effect, permeability across the blood–brain barrier (BBB) represents a central issue. Niosomes are nanovesicles that can be functionalized with specific ligands selectively recognized by transporters expressed on the BBB. In this work, the activity of ADM_09 on neocortex cultures was studied, and an efficient formulation to cross the BBB was developed with the aim of increasing the concentration of ADM_09 into the brain and selectively delivering it to the CNS rapidly after parenteral administration.


2014 ◽  
Vol 307 (9) ◽  
pp. R1092-R1100 ◽  
Author(s):  
Brian Kinsman ◽  
James Cowles ◽  
Jennifer Lay ◽  
Sarah S. Simmonds ◽  
Kirsteen N. Browning ◽  
...  

Recent studies suggest the ability of the central nervous system to detect changes in osmolality is mediated by products of the genes encoding the transient receptor potential vanilloid-1 (TRPV1) or vanilloid-4 (TRPV4) channel. The purpose of the present study was to determine whether deletion of TRPV1 and/or TRPV4 channels altered thirst responses to cellular dehydration in mice. Injection of 0.5 or 1.0 M NaCl produced dose-dependent increases in cumulative water intakes of wild-type (WT), TRPV1−/−, TRPV4−/−, and TRPV1−/−V4−/− mice. However, there were no differences in cumulative water intakes between WT versus any other strain despite similar increases in plasma electrolytes and osmolality. Similar results were observed after injection of hypertonic mannitol. This was a consistent finding regardless of the injection route (intraperitoneal vs. subcutaneous) or timed access to water (delayed vs. immediate). There were also no differences in cumulative intakes across strains after injection of 0.15 M NaCl or during a time-controlled period (no injection). Chronic hypernatremia produced by sole access to 2% NaCl for 48 h also produced similar increases in water intake across strains. In a final set of experiments, subcutaneous injection of 0.5 M NaCl produced similar increases in the number of Fos-positive nuclei within the organum vasculosum of the lamina terminalis and median preoptic nucleus across strains but significantly smaller number in the subfornical organ of WT versus TRPV1−/−V4−/− mice. Collectively, these findings suggest that TRPV1 and/or TRPV4 channels are not the primary mechanism by which the central nervous system responds to cellular dehydration during hypernatremia or hyperosmolality to increase thirst.


2008 ◽  
Vol 87 (3) ◽  
pp. 262-266 ◽  
Author(s):  
A.M. Patwardhan ◽  
J. Vela ◽  
J. Farugia ◽  
K. Vela ◽  
K.M. Hargreaves

Orofacial inflammation is associated with prostaglandin release and the sensitization of nociceptive receptors such as the transient receptor potential subtype V1 (TRPV1). We hypothesized that certain PGE2 receptor subtypes (EP1–EP4) are co-expressed with TRPV1 in trigeminal nociceptors and sensitize responses to a TRPV1 agonist, capsaicin. Accordingly, combined in situ hybridization was performed with immunohistochemistry on rat trigeminal ganglia. We next evaluated the effects of specific EP2 and EP3 agonists (butaprost and sulprostone) in cultured trigeminal ganglia neurons. The results showed that EP2 and EP3 are expressed in trigeminal neurons (58% and 53% of total neurons, respectively) and are co-expressed in TRPV1-positive neurons (64% and 67 % of TRPV1-positive neurons, respectively). Moreover, most of the cells expressing EP2 or EP3 mRNA were of small to medium diameter (< 30 μm). The application of butaprost and sulprostone triggered neuropeptide exocytosis, and butaprost sensitized capsaicin responses. Analysis of these data, collectively, supports the hypothesis that prostaglandins regulate trigeminal TRPV1 nociceptors via activation of the EP2 and EP3 receptors.


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