Oxtr/TRPV1 expression and acclimation of skeletal muscle to cold-stress in male mice

2021 ◽  
Author(s):  
Elena Conte ◽  
Adele Romano ◽  
Michela De Bellis ◽  
Maria Luisa De Ceglia ◽  
Maria Rosaria Carratù ◽  
...  

We explored the involvement of Oxytocin receptor (Oxtr)/ Transient-receptor-potential-vanilloid-1 (TRPV1) genes and Oxytocin (Oxt) on the adaptation of skeletal muscle to cold stress challenge in mice. Oxtr expression in hypothalamic paraventricular (PVN), supraoptic nuclei (SON), and hippocampus (HIPP) were evaluated by immunohistochemistry in parallel with the measurement of circulating Oxt. The Oxtr and TRPV1 gene expression in Soleus (SOL) and Tibialis Anterior (TA) muscles were investigated by RT-PCR. Histological studies of the cardiac muscle after cold stress were also performed. Male mice (n=15) were divided into controls maintained at room temperature (RT=24°C), exposed to cold stress (CS) at T=4°C for 6 hours (6h), and 5 days (5d). Immunohistochemical studies showed that Oxtr protein expression increased by 2-fold (p=0.01) in PVN and by 1.5-fold (p=0.0001) in HIPP after 6h and 5d CS, but decreased by 2-fold (p=0.026) in SON at 5d. Both Oxtr and TRPV1 gene expression increased after 6h and 5d CS in SOL and TA muscles. Oxtr vs TRPV1 gene expression in SOL and TA muscles evaluated by regression analysis was linearly correlated following CS at 6h and 5d but not at control temperature of 24+1°C, supporting the hypothesis of coupling between these genes. The circulating levels of Oxt are unaffected after 6h CS but decreased by 0.2-fold (p=0.0141) after 5d CS. This is the first report that Oxtr and TRPV1 expression are upregulated in response to cold acclimation in skeletal muscle. The up-regulation of Oxtr in PVN and HIPP balances the decrease of circulating Oxt.

Life ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 233
Author(s):  
Aude Lafoux ◽  
Sabine Lotteau ◽  
Corinne Huchet ◽  
Sylvie Ducreux

The transient receptor potential vanilloid 1 (TRPV1) belongs to the transient receptor potential superfamily of sensory receptors. TRPV1 is a non-selective cation channel permeable to Ca2+ that is capable of detecting noxious heat temperature and acidosis. In skeletal muscles, TRPV1 operates as a reticular Ca2+-leak channel and several TRPV1 mutations have been associated with two muscle disorders: malignant hyperthermia (MH) and exertional heat stroke (EHS). Although TRPV1−/− mice have been available since the 2000s, TRPV1’s role in muscle physiology has not been thoroughly studied. Therefore, the focus of this work was to characterize the contractile phenotype of skeletal muscles of TRPV1-deficient mice at rest and after four weeks of exercise. As MS and EHS have a higher incidence in men than in women, we also investigated sex-related phenotype differences. Our results indicated that, without exercise, TRPV1−/− mice improved in vivo muscle strength with an impairment of skeletal muscle in vitro twitch features, i.e., delayed contraction and relaxation. Additionally, exercise appeared detrimental to TRPV1−/− slow-twitch muscles, especially in female animals.


2021 ◽  
Author(s):  
Hsien-Yin Liao ◽  
Yi-Wen Lin

Abstract Background Fibromyalgia pain lacks objective parameters to measure treatment efficacy. Fibromyalgia patients suffer from chronic and persistent widespread pain and generalized tenderness. Transient receptor potential V1 (TRPV1), which is reported as a Ca2+ permeable ion channel that can be activated by inflammation, is reported to be involved in the development of fibromyalgia pain. Methods The current study explored the transient receptor potential vanilloid 1 (TRPV1) channel functions as a noxious sensory input in mice cold stress model. It remains unknown whether electroacupuncture (EA) attenuates fibromyalgia pain or affects the TRPV1 pathway. Results We show that cold stress increases mechanical and thermal pain (Day 7: mechanical: 1.69 ± 0.41 g; thermal: 4.68 ± 0.56 s), and that EA and Trpv1 deletion counter this increase. EA and Trpv1 deletion reduced the cold stress-induced increase in inflammatory mediators and TRPV1-related molecules in the hypothalamus, periaqueductal gray (PAG), and cerebellum of mice. Conclusions Our results imply that EA has an analgesic effect associated with TRPV1 downregulation. We provide novel evidence that these inflammatory mediators can modulate the TRPV1 signaling pathway and suggest new potential therapeutic targets for fibromyalgia pain.


2016 ◽  
Vol 310 (3) ◽  
pp. F230-F236 ◽  
Author(s):  
Chien-Te Lee ◽  
Hwee-Yeong Ng ◽  
Yueh-Ting Lee ◽  
Li-Wen Lai ◽  
Yeong-Hau H. Lien

Calbindin-D28k (CBD-28k) is a calcium binding protein located in the distal convoluted tubule (DCT) and plays an important role in active calcium transport in the kidney. Loop and thiazide diuretics affect renal Ca and Mg handling: both cause Mg wasting, but have opposite effects on Ca excretion as loop diuretics increase, but thiazides decrease, Ca excretion. To understand the role of CBD-28k in renal Ca and Mg handling in response to diuretics treatment, we investigated renal Ca and Mg excretion and gene expression of DCT Ca and Mg transport molecules in wild-type (WT) and CBD-28k knockout (KO) mice. Mice were treated with chlorothiazide (CTZ; 50 mg·kg−1·day−1) or furosemide (FSM; 30 mg·kg−1·day−1) for 3 days. To avoid volume depletion, salt was supplemented in the drinking water. Urine Ca excretion was reduced in WT, but not in KO mice, by CTZ. FSM induced similar hypercalciuria in both groups. DCT Ca transport molecules, including transient receptor potential vanilloid 5 (TRPV5), TRPV6, and CBD-9k, were upregulated by CTZ and FSM in WT, but not in KO mice. Urine Mg excretion was increased and transient receptor potential subfamily M, member 6 (TRPM6) was upregulated by both CTZ and FSM in WT and KO mice. In conclusion, CBD-28k plays an important role in gene expression of DCT Ca, but not Mg, transport molecules, which may be related to its being a Ca, but not a Mg, intracellular sensor. The lack of upregulation of DCT Ca transport molecules by thiazides in the KO mice indicates that the DCT Ca transport system is critical for Ca conservation by thiazides.


Author(s):  
Rie Ishizawa ◽  
Han-Kyul Kim ◽  
Norio Hotta ◽  
Gary A. Iwamoto ◽  
Jere H. Mitchell ◽  
...  

The blood pressure response to exercise is exaggerated in type 2 diabetes (T2D). However, the underlying mechanisms remain unclear. It is hypothesized that one mechanism mediating the potentiated cardiovascular response in T2D is the sensitization of chemically sensitive afferent neurons by activation of metaboreceptors. To test this hypothesis, we examined TRPV1 (transient receptor potential vanilloid 1)-induced cardiovascular responses in vivo and muscle afferent discharge ex vivo in T2D rats. Additionally, TRPV1 and PKC (protein kinase C) protein levels in dorsal root ganglia subserving skeletal muscle were assessed. For 14 to 16 weeks, Sprague-Dawley rats were given either a normal diet (control) or a high-fat diet in combination with a low dose (35 and 25 mg/kg) of streptozotocin (T2D). Administration of capsaicin, TRPV1 agonist, in hindlimb evoked significantly greater increases in mean arterial pressure and renal sympathetic nerve activity in decerebrated T2D than control. In a muscle-nerve preparation, the discharge to capsaicin exposure in group IV afferents isolated from T2D was likewise significantly augmented at a magnitude that was proportional to glucose concentration. Moreover, the discharge to capsaicin was potentiated by acute exposure of group IV afferents to a high-glucose environment. T2D showed significantly increased phospholyrated-TRPV1 and -PKCα levels in dorsal root ganglia neurons as compared with control. These findings suggest that group IV muscle afferents are sensitized by PKC-induced TRPV1 overactivity in early stage T2D with hyperglycemia and, thereby, may contribute to the potentiated circulatory response to TRPV1 activation in the disease.


2012 ◽  
Vol 4 (2) ◽  
pp. 97-107 ◽  
Author(s):  
Yingmei Zhang ◽  
Linlin Li ◽  
Yinan Hua ◽  
Jennifer M. Nunn ◽  
Feng Dong ◽  
...  

Abstract Cold exposure is associated with oxidative stress and cardiac dysfunction. The endothelin (ET) system, which plays a key role in myocardial homeostasis, may participate in cold exposure-induced cardiovascular dysfunction. This study was designed to examine the role of ET-1 in cold stress-induced cardiac geometric and contractile responses. Wild-type (WT) and ETA receptor knockout (ETAKO) mice were assigned to normal or cold exposure (4°C) environment for 2 and 5 weeks prior to evaluation of cardiac geometry, contractile, and intracellular Ca2+ properties. Levels of the temperature sensor transient receptor potential vanilloid (TRPV1), mitochondrial proteins for biogenesis and oxidative phosphorylation, including UCP2, HSP90, and PGC1α were evaluated. Cold stress triggered cardiac hypertrophy, depressed myocardial contractile capacity, including fractional shortening, peak shortening, and maximal velocity of shortening/relengthening, reduced intracellular Ca2+ release, prolonged intracellular Ca2+ decay and relengthening duration, generation of ROS and superoxide, as well as apoptosis, the effects of which were blunted by ETAKO. Western blotting revealed downregulated TRPV1 and PGC1α as well as upregulated UCP2 and activation of GSK3β, GATA4, and CREB in cold-stressed WT mouse hearts, which were obliterated by ETAKO. Levels of HSP90, an essential regulator for thermotolerance, were unchanged. The TRPV1 agonist SA13353 attenuated whereas TRPV1 antagonist capsazepine mimicked cold stress- or ET-1-induced cardiac anomalies. The GSK3β inhibitor SB216763 ablated cold stress-induced cardiac contractile (but not remodeling) changes and ET-1-induced TRPV1 downregulation. These data suggest that ETAKO protects against cold exposure-induced cardiac remodeling and dysfunction mediated through TRPV1 and mitochondrial function.


2016 ◽  
Vol 5 (4) ◽  
pp. 131-134
Author(s):  
Iizuka Michiro ◽  
◽  
Hirata Ayumu ◽  
Abe Noriaki ◽  
Jobu Kohei ◽  
...  

Ginger rhizome (Zingiber officinale) exhibits multiple pharmacological actions. For example, its pungent components target the transient receptor potential vanilloid 1 (TRPV1) ion channel and thus contribute to swallowing reflex recovery by elevating the neuropeptide substance P. However, the precise mechanism underlying this action remains unclear. To examine TRPV1 and substance P gene expression in the mouse tongue in response to stimulation by orally administered ginger, quantitative real-time polymerase chain reaction and immunohistochemistry were performed to evaluate mRNA and protein expression. TRPV1 mRNA expression in the mouse tongue was upregulated 30 min after oral ginger stimulation. In the gingerstimulated mouse, TRPV1 protein expression was increased and concentrated in the plasma membranes of the mucous glandular cells of the tongue epithelium. No significant differences in substance P mRNA expression relative to the control were observed after ginger stimulation. However, immunohistochemistry revealed that the amount of substance P protein expression increased in the mucous glandular cells of the tongue epithelium in ginger-stimulated mice, and this expression appeared to concentrate in the secretory granules of these cells. Activation of TRPV1 promotes the secretion of substance P in saliva, and clinically, saliva levels of substance P can be measured noninvasively and can provide a useful biomarker of the swallowing function. An increased level of substance P in the saliva could indicate improved dysphagia. Our data suggest that ginger activates TRPV1 and promotes the secretion of substance P in saliva. Ginger is therefore expected to serve as a functional agent for improving dysphagia.


2020 ◽  
Vol 21 (7) ◽  
pp. 2507 ◽  
Author(s):  
Bence András Lázár ◽  
Gábor Jancsó ◽  
Péter Sántha

Insulin, besides its pivotal role in energy metabolism, may also modulate neuronal processes through acting on insulin receptors (InsRs) expressed by neurons of both the central and the peripheral nervous system. Recently, the distribution and functional significance of InsRs localized on a subset of multifunctional primary sensory neurons (PSNs) have been revealed. Systematic investigations into the cellular electrophysiology, neurochemistry and morphological traits of InsR-expressing PSNs indicated complex functional interactions among specific ion channels, proteins and neuropeptides localized in these neurons. Quantitative immunohistochemical studies have revealed disparate localization of the InsRs in somatic and visceral PSNs with a dominance of InsR-positive neurons innervating visceral organs. These findings suggested that visceral spinal PSNs involved in nociceptive and inflammatory processes are more prone to the modulatory effects of insulin than somatic PSNs. Co-localization of the InsR and transient receptor potential vanilloid 1 (TRPV1) receptor with vasoactive neuropeptides calcitonin gene-related peptide and substance P bears of crucial importance in the pathogenesis of inflammatory pathologies affecting visceral organs, such as the pancreas and the urinary bladder. Recent studies have also revealed significant novel aspects of the neurotrophic propensities of insulin with respect to axonal growth, development and regeneration.


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