scholarly journals Effects of Ca2+-Activated Cl- Channel ANO1inhibitors on Pacemaker Activity in Interstitial Cells of Cajal

2018 ◽  
Vol 51 (6) ◽  
pp. 2887-2899 ◽  
Author(s):  
Seok Choi ◽  
Hyun Goo Kang ◽  
Mei Jin Wu ◽  
Han Yi Jiao ◽  
Dong Hoon Shin ◽  
...  
Keyword(s):  
Interstitial Cells Of Cajal ◽  
Interstitial Cells ◽  
Patch Clamp Recording ◽  
Cl Channel ◽  
Pacemaker Channels ◽  
Pacemaker Potentials ◽  
Small Intestinal ◽  
Cells Of Cajal ◽  
Ca2 Channels ◽  
Do So

Background/Aims: Anoctamin1 (Ca2+-activated Cl- channel, ANO1) is a specific marker of the interstitial cells of Cajal (ICC) in the gastrointestinal tract, and are candidate proteins that can function as pacemaker channels. Recently, novel selective ANO1 inhibitors were discovered and used to study Ca2+-activated Cl- channels. Therefore, to investigate whether ANO1 channels function as pacemaker channels, selective ANO1 inhibitors were tested with respect to the pacemaker potentials in ICC. Methods: Whole-cell patch-clamp recording, RT-PCR, and intracellular Ca2+ ([Ca2+]i) imaging were performed in cultured ICC obtained from mice. Results: Though CaCCinh-A01 (5 µM), T16Ainh-A01 (5 µM), and MONNA (5 µM) (selective ANO1 inhibitors) blocked the generation of pacemaker potentials in colonic ICC, they did not do so in small intestinal ICC. Though nifulmic acid (10 µM) and DIDS (10 µM) (classical Ca2+-activated Cl- channel inhibitors) also had no effect in small intestinal ICC, they suppressed the generation of pacemaker potentials in colonic ICC. In addition, knockdown of ANO1 reduced the pacemaker potential frequency in colonic ICC alone. Though ANO1 inhibitors suppressed [Ca2+]i oscillations in colonic ICC, they did not do so in small intestinal ICC. T-type Ca2+ channels were expressed in the both the small intestinal and colonic ICC, but mibefradil (5 µM) and NiCl2 (30 µM) (T-type Ca2+ channel inhibitors) inhibited the generation of pacemaker potentials in colonic ICC alone. Conclusion: These results indicate that though ANO1 and T-type Ca2+ channels participate in generating pacemaker potentials in colonic ICC, they do not do so in small intestinal ICC. Therefore, the mechanisms underlying pacemaking in ICC might be different in the small intestine and the colon.

Sodium current in human small intestinal interstitial cells of cajal

2001 ◽  
Vol 120 (5) ◽  
pp. A201-A201 ◽  
Author(s):  
P STREGE ◽  
A RICH ◽  
Y OU ◽  
S GIBBONS ◽  
M SARR ◽  
...  
Keyword(s):  
Interstitial Cells Of Cajal ◽  
Sodium Current ◽  
Interstitial Cells ◽  
Small Intestinal ◽  
Cells Of Cajal

scholarly journals Magnolia Officinalis Bark Extract Induces Depolarization of Pacemaker Potentials Through M2 and M3 Muscarinic Receptors in Cultured Murine Small Intestine Interstitial Cells of Cajal

2017 ◽  
Vol 43 (5) ◽  
pp. 1790-1802 ◽  
Author(s):  
Hyun Jung Kim ◽  
Taewon Han ◽  
Yun Tai Kim ◽  
Insuk So ◽  
Byung Joo Kim
Keyword(s):  
Receptor Antagonist ◽  
Interstitial Cells Of Cajal ◽  
Interstitial Cells ◽  
Pacemaker Potential ◽  
Pacemaker Potentials ◽  
Magnolia Officinalis ◽  
Cells Of Cajal ◽  
Gi Motility

Background: Magnolia officinalis Rehder and EH Wilson (M. officinalis) are traditional Chinese medicines widely used for gastrointestinal (GI) tract motility disorder in Asian countries. We investigated the effects of an ethanol extract of M. officinalis (MOE) on the pacemaker potentials of cultured interstitial cells of Cajal (ICCs) in vitro and its effects on GI motor functions in vivo. Methods: We isolated ICCs from small intestines, and the whole-cell patch-clamp configuration was used to record the pacemaker potentials in cultured ICCs in vitro. Both gastric emptying (GE) and intestinal transit rates (ITRs) were investigated in normal and GI motility dysfunction (GMD) mice models in vivo. Results: MOE depolarized ICC pacemaker potentials dose-dependently. Pretreatment with methoctramine (a muscarinic M2 receptor antagonist) and 4-DAMP (a muscarinic M3 receptor antagonist) inhibited the effects of MOE on the pacemaker potential relative to treatment with MOE alone. In addition, MOE depolarized pacemaker potentials after pretreatment with Y25130 (a 5-HT3 receptor antagonist), GR113808 (a 5-HT4 receptor antagonist) or SB269970 (a 5-HT7 receptor antagonist). However, pretreatment with RS39604 (a 5-HT4 receptor antagonist) blocked MOE-induced pacemaker potential depolarizations. Intracellular GDPβS inhibited MOE-induced pacemaker potential depolarization, as did pretreatment with Ca2+ free solution or thapsigargin. In normal mice, the GE and ITR values were significantly and dose-dependently increased by MOE. In loperamide-and cisplatin-induced GE delay models, MOE administration reversed the GE deficits. The ITRs of the GMD mice were significantly reduced relative to those of normal mice, which were significantly and dose-dependently reversed by MOE. Conclusion: These results suggest that MOE dose-dependently depolarizes ICCs pacemaker potentials through M2 and M3 receptors via internal and external Ca2+ regulation through G protein pathways in vitro. Moreover, MOE increased GE and ITRs in vivo in normal and GMD mouse models. Taken together, the results of this study show that MOE have the potential for development as a gastroprokinetic agent in GI motility function.

scholarly journals Menthol Modulates Pacemaker Potentials through TRPA1 Channels in Cultured Interstitial Cells of Cajal from Murine Small Intestine

2016 ◽  
Vol 38 (5) ◽  
pp. 1869-1882 ◽  
Author(s):  
Hyun Jung Kim ◽  
Jinhong Wie ◽  
Insuk So ◽  
Myeong Ho Jung ◽  
Ki-Tae Ha ◽  
...  
Keyword(s):  
Small Intestine ◽  
Membrane Potential ◽  
Interstitial Cells Of Cajal ◽  
Rho Kinase ◽  
Thromboxane A2 ◽  
Interstitial Cells ◽  
Dependent Manner ◽  
Induced Membrane ◽  
Pacemaker Potentials ◽  
Cells Of Cajal

Background/Aims: ICCs are the pacemaker cells responsible for slow waves in gastrointestinal (GI) smooth muscle, and generate periodic pacemaker potentials in current-clamp mode. Methods: The effects of menthol on the pacemaker potentials of cultured interstitial cells of Cajal (ICCs) from mouse small intestine were studied using the whole cell patch clamp technique. Results: Menthol (1 - 10 μM) was found to induce membrane potential depolarization in a concentration-dependent manner. The effects of various TRP channel antagonists were examined to investigate the receptors involved. The addition of the TRPM8 antagonist, AMTB, did not block menthol-induced membrane potential depolarizations, but TRPA1 antagonists (A967079 or HC-030031) blocked the effects of menthol, as did intracellular GDPβS. Furthermore, external and internal Ca2+ levels were found to depolarize menthol-induced membrane potentials, whereas external Na+ was not. Y-27632 (a Rho kinase inhibitor), SC-560 (a selective COX 1 inhibitor), NS-398 (a selective COX 2 inhibitor), ozagrel (a thromboxane A2 synthase inhibitor) and SQ-29548 (highly selective thromboxane receptor antagonist) were used to investigate the involvements of Rho-kinase, cyclooxygenase (COX), and the thromboxane pathway in menthol-induced membrane potential depolarizations, and all inhibitors were found to block the effect of menthol. Conclusions: These results suggest that menthol-induced membrane potential depolarizations occur in a G-protein-, Ca2+-, Rho-kinase-, COX-, and thromboxane A2-dependent manner via TRPA1 receptor in cultured ICCs in murine small intestine. The study shows ICCs are targeted by menthol and that this interaction can affect intestinal motility.

Rikkunshito Depolarizes Pacemaker Potentials of Cultured Interstitial Cells of Cajal through Ghrelin Receptors in Murine Small Intestine

Digestion ◽  
2019 ◽  
Vol 101 (3) ◽  
pp. 227-238 ◽  
Author(s):  
Jeong Nam Kim ◽  
Joo Hyun Nam ◽  
Jong Rok Lee ◽  
Sang Chan Kim ◽  
Young Kyu Kwon ◽  
...  
Keyword(s):  
Small Intestine ◽  
Interstitial Cells Of Cajal ◽  
Interstitial Cells ◽  
Pacemaker Potentials ◽  
Ghrelin Receptors ◽  
Murine Small Intestine ◽  
Cells Of Cajal

Pacemaker potentials generated by interstitial cells of Cajal in the murine intestine

2005 ◽  
Vol 288 (3) ◽  
pp. C710-C720 ◽  
Author(s):  
Yoshihiko Kito ◽  
Sean M. Ward ◽  
Kenton M. Sanders
Keyword(s):  
Interstitial Cells Of Cajal ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Interstitial Cells ◽  
Slow Waves ◽  
Pacemaker Activity ◽  
Dependent Manner ◽  
Plateau Potential ◽  
Pacemaker Potentials ◽  
Cells Of Cajal

Pacemaker potentials were recorded in situ from myenteric interstitial cells of Cajal (ICC-MY) in the murine small intestine. The nature of the two components of pacemaker potentials (upstroke and plateau) were investigated and compared with slow waves recorded from circular muscle cells. Pacemaker potentials and slow waves were not blocked by nifedipine (3 μM). In the presence of nifedipine, mibefradil, a voltage-dependent Ca2+ channel blocker, reduced the amplitude, frequency, and rate of rise of upstroke depolarization (d V/d tmax) of pacemaker potentials and slow waves in a dose-dependent manner (1–30 μM). Mibefradil (30 μM) changed the pattern of pacemaker potentials from rapidly rising, high-frequency events to slowly depolarizing, low-frequency events with considerable membrane noise (unitary potentials) between pacemaker potentials. Caffeine (3 mM) abolished pacemaker potentials in the presence of mibefradil. Pinacidil (10 μM), an ATP-sensitive K+ channel opener, hyperpolarized ICC-MY and increased the amplitude and d V/d tmax without affecting frequency. Pinacidil hyperpolarized smooth muscle cells and attenuated the amplitude and d V/d tmax of slow waves without affecting frequency. The effects of pinacidil were blocked by glibenclamide (10 μM). These data suggest that slow waves are electrotonic potentials driven by pacemaker potentials. The upstroke component of pacemaker potentials is due to activation of dihydropyridine-resistant Ca2+ channels, and this depolarization entrains pacemaker activity to create the plateau potential. The plateau potential may be due to summation of unitary potentials generated by individual or small groups of pacemaker units in ICC-MY. Entrainment of unitary potentials appears to depend on Ca2+ entry during upstroke depolarization.

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