TRPC5 as a candidate for the nonselective cation channel activated by muscarinic stimulation in murine stomach

2003 ◽  
Vol 284 (4) ◽  
pp. G604-G616 ◽  
Author(s):  
Young Mee Lee ◽  
Byung Joo Kim ◽  
Hyun Jin Kim ◽  
Dong Ki Yang ◽  
Mei Hong Zhu ◽  
...  

We investigated which transient receptor potential (TRP) channel is responsible for the nonselective cation channel (NSCC) activated by carbachol (CCh) in murine stomach with RT-PCR and the electrophysiological method. All seven types of TRP mRNA were detected in murine stomach with RT-PCR. When each TRP channel was expressed, the current-voltage relationship of mTRP5 was most similar to that recorded in murine gastric myocytes. mTRP5 showed a conductance order of Cs+ > K+ > Na+, similar to that in the murine stomach. With 0.2 mM GTPγS in the pipette solution, the current was activated transiently in both NSCC in the murine stomach and the expressed mTRP5. Both NSCC activated by CCh in murine stomach and mTRP5 were inhibited by intracellularly applied anti-Gq/11 antibody, PLC inhibitor U-73122, IICR inhibitor 2-aminoethoxydiphenylborate, and nonspecific cation channel blockers La3+ and flufenamate. There were two other unique properties. Both the native NSCC and mTRP5 were activated by 1-oleoyl-2-acetyl-sn-glycerol. Without the activation of NSCC by CCh, the NSCC in murine stomach was constitutively active like mTRP5. From the above results, we suggest that mTRP5 might be a candidate for the NSCC activated by ACh or CCh in murine stomach.

2004 ◽  
Vol 286 (6) ◽  
pp. G983-G991 ◽  
Author(s):  
Lei Zhang ◽  
Sarahlouise Jones ◽  
Kate Brody ◽  
Marcello Costa ◽  
Simon J. H. Brookes

A number of transient receptor potential (TRP) channels has recently been shown to mediate cutaneous thermosensitivity. Sensitivity to warm and cool stimuli has been demonstrated in both human and animal gastrointestinal tract; however, the molecular mechanisms that underlie this have not been determined. Vagal afferent neurons with cell bodies in the nodose ganglion are known to mediate nonnociceptive sensation from the upper gut. In this study, isolated cultured nodose ganglion from the mouse neurons showed changes in cytoplasmic-free Ca2+concentrations over a range of temperatures, as well as to icilin (a TRPM8 and TRPN1 agonist) and capsaicin (a TRPV1 agonist). RT-PCR was used to show the presence of six temperature-sensitive TRP channel transcripts (TRPV1–4, TRPN1, and TRPM8) in whole nodose ganglia. In addition, RT-PCR of single nodose cell bodies, which had been retrogradely labeled from the upper gut, detected transcripts for TRPV1, TRPV2, TRPV4, TRPN1, and TRPM8 in a proportion of cells. Immunohistochemical labeling detected TRPV1 and TRPV2 proteins in nodose ganglia. The presence of TRP channel transcripts and proteins was also detected in cells within several regions of the gastrointestinal tract. Our results reveal that TRP channels are present in subsets of vagal afferent neurons that project to the stomach and may confer temperature sensitivity on these cells.


2012 ◽  
Vol 524 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Hong-Wei Dong ◽  
James C. Davis ◽  
ShengYuan Ding ◽  
Qiang Nai ◽  
Fu-Ming Zhou ◽  
...  

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 397
Author(s):  
Andras Szollosi

The transient receptor potential melastatin (TRPM) family belongs to the superfamily of TRP ion channels. It consists of eight family members that are involved in a plethora of cellular functions. TRPM2 is a homotetrameric Ca2+-permeable cation channel activated upon oxidative stress and is important, among others, for body heat control, immune cell activation and insulin secretion. Invertebrate TRPM2 proteins are channel enzymes; they hydrolyze the activating ligand, ADP-ribose, which is likely important for functional regulation. Since its cloning in 1998, the understanding of the biophysical properties of the channel has greatly advanced due to a vast number of structure–function studies. The physiological regulators of the channel have been identified and characterized in cell-free systems. In the wake of the recent structural biochemistry revolution, several TRPM2 cryo-EM structures have been published. These structures have helped to understand the general features of the channel, but at the same time have revealed unexplained mechanistic differences among channel orthologues. The present review aims at depicting the major research lines in TRPM2 structure-function. It discusses biophysical properties of the pore and the mode of action of direct channel effectors, and interprets these functional properties on the basis of recent three-dimensional structural models.


2014 ◽  
Vol 307 (9) ◽  
pp. H1339-H1352 ◽  
Author(s):  
Gaku Oguri ◽  
Toshiaki Nakajima ◽  
Yumiko Yamamoto ◽  
Nami Takano ◽  
Tomofumi Tanaka ◽  
...  

Cardiac fibroblasts contribute to the pathogenesis of cardiac remodeling. Methylglyoxal (MG) is an endogenous carbonyl compound produced under hyperglycemic conditions, which may play a role in the development of pathophysiological conditions including diabetic cardiomyopathy. However, the mechanism by which this occurs and the molecular targets of MG are unclear. We investigated the effects of MG on Ca2+ signals, its underlying mechanism, and cell cycle progression/cell differentiation in human cardiac fibroblasts. The conventional and quantitative real-time RT-PCR, Western blot, immunocytochemical analysis, and intracellular Ca2+ concentration [Ca2+]i measurement were applied. Cell cycle progression was assessed using the fluorescence activated cell sorting. MG induced Ca2+ entry concentration dependently. Ruthenium red (RR), a general cation channel blocker, and HC030031 , a selective transient receptor potential ankyrin 1 (TRPA1) antagonist, inhibited MG-induced Ca2+ entry. Treatment with aminoguanidine, a MG scavenger, also inhibited it. Allyl isothiocyanate, a selective TRPA1 agonist, increased Ca2+ entry. The use of small interfering RNA to knock down TRPA1 reduced the MG-induced Ca2+ entry as well as TRPA1 mRNA expression. The quantitative real-time RT-PCR analysis showed the prominent existence of TRPA1 mRNA. Expression of TRPA1 protein was confirmed by Western blotting and immunocytochemical analyses. MG promoted cell cycle progression from G0/G1 to S/G2/M, which was suppressed by HC030031 or RR. MG also enhanced α-smooth muscle actin expression. The present results suggest that methylglyoxal activates TRPA1 and promotes cell cycle progression and differentiation in human cardiac fibroblasts. MG might participate the development of pathophysiological conditions including diabetic cardiomyopathy via activation of TRPA1.


2013 ◽  
Vol 288 (21) ◽  
pp. 15303-15317 ◽  
Author(s):  
Makoto Ihara ◽  
Shin Hamamoto ◽  
Yohei Miyanoiri ◽  
Mitsuhiro Takeda ◽  
Masatsune Kainosho ◽  
...  

2001 ◽  
Vol 280 (5) ◽  
pp. L870-L880 ◽  
Author(s):  
Sharon S. McDaniel ◽  
Oleksandr Platoshyn ◽  
Jian Wang ◽  
Ying Yu ◽  
Michele Sweeney ◽  
...  

Agonist-induced increases in cytosolic Ca2+ concentration ([Ca2+]cyt) in pulmonary artery (PA) smooth muscle cells (SMCs) consist of a transient Ca2+ release from intracellular stores followed by a sustained Ca2+ influx. Depletion of intracellular Ca2+ stores triggers capacitative Ca2+ entry (CCE), which contributes to the sustained increase in [Ca2+]cyt and the refilling of Ca2+ into the stores. In isolated PAs superfused with Ca2+-free solution, phenylephrine induced a transient contraction, apparently by a rise in [Ca2+]cyt due to Ca2+ release from the intracellular stores. The transient contraction lasted for 3–4 min until the Ca2+ store was depleted. Restoration of extracellular Ca2+ in the presence of phentolamine produced a contraction potentially due to a rise in [Ca2+]cyt via CCE. The store-operated Ca2+ channel blocker Ni2+ reduced the store depletion-activated Ca2+ currents, decreased CCE, and inhibited the CCE-mediated contraction. In single PASMCs, we identified, using RT-PCR, five transient receptor potential gene transcripts. These results suggest that CCE, potentially through transient receptor potential-encoded Ca2+ channels, plays an important role in agonist-mediated PA contraction.


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