Effects of ATP on Pacemaker Activity of Interstitial Cells of Cajal from the Mouse Small Intestine.

Purinergic receptors play an important role in regulating gastrointestinal (GI) motility. Interstitial cells of Cajal (ICCs) are pacemaker cells that regulate GI smooth muscle activity. We studied the functional roles of external adenosine 5'-triphosphate (ATP) on pacemaker activity in cultured ICCs from mouse small intestines by using the whole-cell patch clamp technique and intracellular Ca ([Ca]) imaging.

Functional effects of β3-adrenoceptor on pacemaker activity in interstitial cells of Cajal from the mouse colon.

We investigated the presence of β3-adrenoceptor and its functional effects on pacemaker potentials in colonic interstitial cells of Cajal (ICCs) from mice. The whole-cell patch clamp technique was used to record pacemaker potentials in cultured ICCs and reverse transcription polymerase chain reaction (RT-PCR) was performed to detect the mRNA transcript levels β-adrenoceptors. The β3-adrenoceptor agonist, BRL37344, reduced the frequency of pacemaker potentials in a concentration-dependent manner.

The possible roles of hyperpolarization-activated cyclic nucleotide channels in regulating pacemaker activity in colonic interstitial cells of Cajal.

Background: Hyperpolarization-activated cyclic nucleotide (HCN) channels are pacemaker channels that regulate heart rate and neuronal rhythm in spontaneously active cardiac and neuronal cells. Interstitial cells of Cajal (ICCs) are also spontaneously active pacemaker cells in the gastrointestinal tract. Here, we investigated the existence of HCN channel and its role on pacemaker activity in colonic ICCs.

Inhibition of pacemaker activity in interstitial cells of Cajal by LPS via NF-κB and MAP kinase.

Aim: To investigate lipopolysaccharide (LPS) related signal transduction in interstitial cells of Cajal (ICCs) from mouse small intestine.

Methods: For this study, primary culture of ICCs was prepared from the small intestine of the mouse. LPS was treated to the cells prior to measurement of the membrane currents by using whole-cell patch clamp technique.

Effects of sphingosine-1-phosphate on pacemaker activity of interstitial cells of Cajal from mouse small intestine.

Interstitial cells of Cajal (ICC) are the pacemaker cells that generate the rhythmic oscillation responsible for the production of slow waves in gastrointestinal smooth muscle. Spingolipids are known to present in digestive system and are responsible for multiple important physiological and pathological processes. In this study, we are interested in the action of sphingosine 1-phosphate (S1P) on ICC.

Action of lipopolysaccharide on interstitial cells of cajal from mouse small intestine.

Background And Purpose: Lipopolysaccharide (LPS) induces intestinal dysmotility by alteration of smooth muscle and enteric neuronal activities. However, there is no report on the modulatory effects of LPS on the interstitial cells of Cajal (ICCs). We investigated the effect of LPS and its signal transduction in ICCs.

Neurotensin modulates pacemaker activity in interstitial cells of Cajal from the mouse small intestine.

Neurotensin, a tridecapeptide localized in the gut to discrete enteroendocrine cells of the small bowel mucosa, is a hormone that plays an important role in gastrointestinal secretion, growth, and motility. Neurotensin has inhibitory and excitatory effects on peristaltic activity and produces contractile and relaxant responses in intestinal smooth muscle. Our objective in this study is to investigate the effects of neurotensin in small intestinal interstitial cells of Cajal (ICC) and elucidate the mechanism.

5-hydroxytryptamine generates tonic inward currents on pacemaker activity of interstitial cells of cajal from mouse small intestine.

In this study we determined whether or not 5-hydroxytryptamine (5-HT) has an effect on the pacemaker activities of interstitial cells of Cajal (ICC) from the mouse small intestine. The actions of 5-HT on pacemaker activities were investigated using a whole-cell patch-clamp technique, intracellular Ca(2+) ([Ca(2+)](i)) analysis, and RT-PCR in ICC. Exogenously-treated 5-HT showed tonic inward currents on pacemaker currents in ICC under the voltage-clamp mode in a dose-dependent manner.

Effects of prostaglandin F2α on small intestinal interstitial cells of Cajal.

Aim: To explore the role of prostaglandin F(2α) (PGF(2α))) on pacemaker activity in interstitial cells of Cajal (ICC) from mouse small intestine.

Methods: In this study, effects of PGF(2α) in the cultured ICC cells were investigated with patch clamp technology combined with Ca(2+) image analysis.

Results: Externally applied PGF(2α) (10 μmol/L) produced membrane depolarization in current-clamp mode and increased tonic inward pacemaker currents in voltage-clamp mode.

The inhibitory effects of hydrogen sulfide on pacemaker activity of interstitial cells of cajal from mouse small intestine.

In this study, we studied whether hydrogen sulfide (H(2)S) has an effect on the pacemaker activity of interstitial cells of Cajal (ICC), in the small intestine of mice. The actions of H(2)S on pacemaker activity were investigated using whole-cell patch-clamp technique, intracellular Ca(2+) analysis at 30 and RT-PCR in cultured mouse intestinal ICC. Exogenously applied sodium hydrogen sulfide (NaHS), a donor of hydrogen sulfide, caused a slight tonic inward current on pacemaker activity in ICC at low concentrations (50 and 100 microM), but at high concentration (500 microM and 1 mM) it seemed to cause light tonic inward currents and then inhibited pacemaker amplitude and pacemaker frequency, and also an increase in the resting currents in the outward direction.

Receptor tyrosine and MAP kinase are involved in effects of H(2)O(2) on interstitial cells of Cajal in murine intestine.

Hydrogen peroxide (H(2)O(2)) is involved in intestinal motility through changes of smooth muscle activity. However, there is no report as to the modulatory effects of H(2)O(2) on interstitial cells of Cajal (ICC). We investigated the H(2)O(2) effects and signal transductions to determine whether the intestinal motility can be modulated through ICC.

Calcitonin gene-related peptide suppresses pacemaker currents by nitric oxide/cGMP-dependent activation of ATP-sensitive K(+) channels in cultured interstitial cells of Cajal from the mouse small intestine.

The effects of calcitonin gene-related peptide (CGRP) on pacemaker currents in cultured interstitial cells of Cajal (ICC) from the mouse small intestine were investigated using the whole-cell patch clamp technique at 30 degrees . Under voltage clamping at a holding potential of -70 mV, CGRP decreased the amplitude and frequency of pacemaker currents and activated outward resting currents. These effects were blocked by intracellular GDPbetaS, a G-protein inhibitor and glibenclamide, a specific ATP-sensitive K(+) channels blocker.

Inhibition of pacemaker currents by nitric oxide via activation of ATP-sensitive K+ channels in cultured interstitial cells of Cajal from the mouse small intestine.

We investigated the role of nitric oxide (NO) in pacemaker activity and signal mechanisms in cultured interstitial cells of Cajal (ICC) of the mouse small intestine using whole cell patch-clamp techniques at 30 degrees C. ICC generated pacemaker potential in the current clamp mode and pacemaker currents at a holding potential of -70 mV. (+/-)-S-nitroso-N-acetylpenicillamine (SNAP; a NO donor) produced membrane hyperpolarization and inhibited the amplitude and frequency of the pacemaker currents, and increased resting currents in the outward direction.

Bradykinin modulates pacemaker currents through bradykinin B2 receptors in cultured interstitial cells of Cajal from the murine small intestine.

We studied the modulation of pacemaker activities by bradykinin in cultured interstitial cells of Cajal (ICC) from murine small intestine with the whole-cell patch-clamp technique. Externally applied bradykinin produced membrane depolarization in the current-clamp mode and increased tonic inward pacemaker currents in the voltage-clamp mode. Pretreatment with bradykinin B1 antagonist did not block the bradykinin-induced effects on pacemaker currents.

Effects of pine needle extract on pacemaker currents in interstitial cells of Cajal from the murine small intestine.

Extracts of pine needles (Pinus densiflora Sieb. et Zucc.) have diverse physiological and pharmacological actions.

Action of imipramine on activated ATP-sensitive K(+) channels in interstitial cells of Cajal from murine small intestine.

Tricyclic antidepressants have been widely used for the treatment of depression and as a therapeutic agent for the altered gastrointestinal (GI) motility of irritable bowel syndrome (IBS). The aim of this study was to clarify whether antidepressants directly modulate pacemaker currents in cultured interstitial cells of Cajal (ICC). We used the whole-cell patch-clamp techniques at 30 degrees C in cultured ICC from the mouse small intestine.

Substance P induces inward current and regulates pacemaker currents through tachykinin NK1 receptor in cultured interstitial cells of Cajal of murine small intestine.

We investigated whether substance P modulates pacemaker currents generated in cultured interstitial cells of Cajal of murine small intestine using whole cell patch-clamp techniques at 30 degrees C. Interstitial cells of Cajal generated spontaneous inward currents (pacemaker currents) at a holding potential of -70 mV. Tetrodotoxin, nifedipine, tetraethylammonium, 4-aminopyridine, or glibenclamide did not change the frequency and amplitude of pacemaker currents.

Noradrenaline inhibits pacemaker currents through stimulation of beta 1-adrenoceptors in cultured interstitial cells of Cajal from murine small intestine.

1. Interstitial cells of Cajal (ICCs) are pacemaker cells that activate the periodic spontaneous inward currents (pacemaker currents) responsible for the production of slow waves in gastrointestinal smooth muscle. The effects of noradrenaline on the pacemaker currents in cultured ICCs from murine small intestine were investigated by using whole-cell patch-clamp techniques at 30 degrees C.