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Circular Smooth Muscle Cells (circular + smooth_muscle_cell)

Distribution by Scientific Domains
Medical Sciences100%

Selected Abstracts

Smooth muscle phenotypic plasticity in mechanical obstruction of the small intestine

NEUROGASTROENTEROLOGY & MOTILITY, Issue 7 2008
J. A. Macdonald
Abstract, Chronic, partial obstruction of the small intestine can dramatically alter peristaltic contractile properties. Morphological studies have revealed hypertrophy of the circular smooth muscle cells in the constricted part of the intestine. In this issue of Neurogastroenterology and Motility, Chen et al. show that hyperplasia and hypertrophy of intestinal smooth muscle cells occur at distinct times in response to partial obstruction of the ileum. Furthermore, the first evidence is provided to link intestinal smooth muscle remodelling during mechanical obstruction with changes in serum response factor and two of its co-regulating factors, myocardin and Elk-1. [source]

Neurally released ATP mediates endothelium-dependent hyperpolarization in the circular smooth muscle cells of chicken anterior mesenteric artery

BRITISH JOURNAL OF PHARMACOLOGY, Issue 7 2005
Marwan Draid
The object of the present study was to clarify the neurotransmitter(s) controlling membrane responses to electrical field stimulation (EFS) in the circular smooth muscle cells of first-order branches of chicken anterior mesenteric artery. EFS (five pulses at 20 Hz, 1 ms) evoked a hyperpolarization of amplitude ,21.6±1.2 mV, total duration 21.8±1.2 s and latency 641.7±81.9 ms. The response was tetrodotoxin-sensitive and nonadrenergic noncholinergic (NANC) in nature. The NANC response was blocked by the nonspecific purinergic antagonist, suramin, indicating that the response is mediated by the neurotransmitter adenosine 5,-triphosphate (ATP). Either desensitization or blockade of P2Y receptor with its putative agonist 2-methylthioATP (1 ,M for 30 min) or with its antagonist cibacron blue F3GA (10 ,M), respectively, abolished the purinergic hyperpolarization. PPADS at concentrations up to 100 ,M had no effect on the EFS-induced response, indicating that this response is mediated through P2Y, but not P2X, receptor. In addition, the response was completely abolished by two specific P2Y1 receptor antagonists, namely, MRS 2179 (300 nM) and A3P5PS (10 ,M). Removal of the endothelium abolished the purinergic hyperpolarization, which was converted, in some preparations, to a small depolarization, indicating that the hyperpolarizing response is endothelium-dependent. The present study suggests that in first-order branches of chicken anterior mesenteric artery, ATP released from perivascular nerves may diffuse to the endothelium-activating P2Y1 receptor to induce release of an inhibitory substance that mediates hyperpolarization in the circular smooth muscle. British Journal of Pharmacology (2005) 146, 983,989. doi:10.1038/sj.bjp.0706413 [source]

ARE GAP JUNCTIONS TRULY INVOLVED IN INHIBITORY NEUROMUSCULAR INTERACTION IN MOUSE PROXIMAL COLON?

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2006
Andrei Sibaev
SUMMARY 1Gap junctions exist between circular muscle cells of the colon and between interstitial cells of Cajal (ICC) in the myenteric plexus of the gastrointestinal tract. They also probably couple intramuscular ICC with smooth muscle cells. Recent functional evidence for this was found in dye-coupling and myoelectrical experiments. 2In the present study, we tested the hypothesis of gap junctions putatively being involved in neuromuscular interaction in mouse colon by using different classes of gap junction blockers. 3Electrical field stimulation of the myenteric plexus elicited tetrodotoxin-sensitive and hexamethonium-independent fast and slow inhibitory junction potentials (fIJP and sIJP, respectively) in circular smooth muscle cells, as evaluated by intracellular recording techniques in impaled smooth muscle cells. Heptanol produced a time-dependent hyperpolarization of the membrane potential (MP) and abolished fIJP and sIJP. Octanol had no effect on the MP and abolished fIJP and sIJP. Carbenoxolone produced a time-dependent depolarization of the MP without any effect on fIJP or sIJP. The connexin 43 mimetic gap junction blocker GAP-27 had no effect on MP, fIJP or sIJP. 4Based on the presently available gap junction blockers we found no evidence that gap junctions are involved in neuromuscular transmission in mouse colon, as suggested by morphological studies. [source]