scholarly journals Characterization of the peristaltic reflex in murine distal colon

2016 ◽  
Vol 94 (2) ◽  
pp. 190-198 ◽  
Author(s):  
Yong Zhang ◽  
William G. Paterson
Keyword(s):  
Smooth Muscle ◽  
Action Potentials ◽  
Purinergic Receptor ◽  
Distal Colon ◽  
Circular Smooth Muscle ◽  
Receptor Blockers ◽  
Balloon Distention ◽  
Mrs 2179 ◽  
Underlying Mechanisms

Ascending and descending neuromuscular reflexes play an important role in gastrointestinal motility. However, the underlying mechanisms in colon are incompletely understood. Nerve stimulation (NS)- and balloon distention (BD)-mediated reflexes in distal colonic circular smooth muscle (CSM) and longitudinal smooth muscle (LSM) of mice were investigated using conventional intracellular recordings. In the CSM, NS evoked ascending purinergic inhibitory junction potentials (IJPs), whereas BD induced atropine-sensitive ascending depolarization with superimposed action potentials (APs). The ascending depolarization reached a peak ∼4–7 s after the onset of distention and gradually returned to baseline after termination of the distention. In the LSM, NS produced an ascending biphasic IJP followed by a train of atropine-sensitive APs. Both stimuli produced similar descending IJPs in CSM and LSM, which were blocked by MRS-2500 and MRS-2179, putative purinergic receptor blockers. These data indicate that in the murine distal colon, descending purinergic inhibition in both CSM and LSM occurs. Ascending responses are more complex, with NS producing both inhibition and excitation to CSM and LSM, and BD evoking only cholinergic excitation.

Characterization of the antigen-induced contraction of colonic smooth muscle from sensitized guinea pigs

1992 ◽  
Vol 262 (1) ◽  
pp. G144-G149 ◽  
Author(s):  
M. S. Barnette ◽  
M. Grous
Keyword(s):  
Smooth Muscle ◽  
Inflammatory Mediators ◽  
Guinea Pigs ◽  
Colonic Motility ◽  
Initial Response ◽  
Late Response ◽  
Circular Smooth Muscle ◽  
Neuronal Interactions ◽  
Leukotriene Antagonist

To study the potential of inflammatory mediators to alter colonic motility, we characterized the response of distal colonic smooth muscle to antigen challenge. Addition of ovalbumin to isolated segments of circular smooth muscle obtained from sensitized guinea pigs produced a biphasic contraction. The initial response consisted of a rapid contraction followed by a late response, which was a more sustained but smaller increase in tone and phasic activity. Interestingly, these two responses could be antagonized differentially. Pretreatment with mepyramine (10 microM) inhibited the initial response, whereas the leukotriene antagonist WY 48252 (10 microM) inhibited the late response. The mast cell stabilizer doxantrazole (0.1 microM) reduced only the late response. Inhibition of cyclooxygenase with meclofenamic acid (1 microM) potentiated both responses, whereas blocking neuronal activity with tetrodotoxin (1 microM) only enhanced the initial response. These data indicate clear differences between the inflammatory mediators important in the initial vs. the late response. The initial response is probably mediated by the release of histamine, with enteric neuronal interactions important in attenuating the magnitude of this response. In contrast, the late response appears to be mediated by the release of peptidyl leukotrienes. In this system, cyclooxygenase products apparently function to decrease the response of the smooth muscle to these mediators. These results suggest that release of mediators during an inflammatory response could profoundly alter colonic motility and that these alterations may be important in the pathophysiological manifestations associated with colonic inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical and Cytochemical Characterization of Extracellular Proteoglycans in the Inner Circular Smooth Muscle Layer of Dog Small Intestine

IUBMB Life ◽  
2002 ◽  
Vol 54 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Olga Maria Szymanski de Toledo ◽  
Mônica Valéria Marquezini ◽  
Kaio Bin Jia ◽  
Mônica de Campos Pinheiro ◽  
Oswaldo Alves Mora
Keyword(s):  
Smooth Muscle ◽  
Small Intestine ◽  
Muscle Layer ◽  
Smooth Muscle Layer ◽  
Circular Smooth Muscle

scholarly journals Effect ofAurantii Fructus Immaturus Flavonoidon the Contraction of Isolated Gastric Smooth Muscle Strips in Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Zhenyu Wu ◽  
Shengsheng Zhang ◽  
Peicai Li ◽  
Xiaofang Lu ◽  
Jiajia Wang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Cyclic Guanosine Monophosphate ◽  
Inhibitory Effect ◽  
Guanosine Monophosphate ◽  
Muscle Strip ◽  
Circular Smooth Muscle ◽  
Gastric Smooth Muscle ◽  
Underlying Mechanisms ◽  
Oxide Synthase ◽  
Dose Dependent

This study was designed to investigate the effect ofAurantii fructus immaturus flavonoid(AFIF) on the contraction of isolated gastric smooth muscle in rats and explore its underlying mechanisms. Isolated antral longitudinal smooth muscle strip (ALSMS) and pyloric circular smooth muscle strip (PCSMS) of rats were suspended in tissue chambers. The responses of ALSMS and PCSMS to administration of AFIF were observed. Cyclic guanosine monophosphate (cGMP) and protein kinase G (PKG) levels of PCSMS were measured by ELISA kits. In this study, AFIF showed no significant effect on ALSMS contraction, but it dose-dependently reduced the mean contraction amplitude of PCSMS. When the concentration of AFIF reached 3000 μg/mL, 6000 μg/mL, and 10000 μg/mL, its inhibitory effect on PCSMS contraction was significant. This effect of AFIF was weakened in Ca2+-rich environment. And Nω-nitro-L-arginine methyl (L-NAME), the inhibitor of nitric oxide synthase (NOS), significantly inhibited AFIF’s action in comparison with control (P<0.05). After incubation with AFIF for 30 min, levels of cGMP and PKG in PCSMS were significantly increased compared with control (P<0.05). Our results suggest that AFIF has a dose-dependent diastolic effect on PCSMS in rats, which may be related to the regulatory pathway of NO/cGMP/PKG/Ca2+.

scholarly journals CHARACTERIZATION OF A UNIQUE MUSCLE CELL LINE

1974 ◽  
Vol 61 (2) ◽  
pp. 398-413 ◽  
Author(s):  
David Schubert ◽  
A. John Harris ◽  
Carrick E. Devine ◽  
Stephen Heinemann
Keyword(s):  
Smooth Muscle ◽  
Cell Line ◽  
Action Potentials ◽  
Creatine Phosphokinase ◽  
Clonal Cell Line ◽  
Excitable Membranes ◽  
Hyperpolarizing Response ◽  
Electrically Excitable Membranes

A clonal cell line derived from a mouse neoplasm is described which shares many properties with smooth muscle. The cells have electrically excitable membranes capable of generating overshooting action potentials, and they contract both spontaneously and with electrical stimulation. They respond to the iontophoretic application of acetylcholine with a depolarizing response, and to norepinephrine with a hyperpolarizing response. Electron microscopy reveals that the cells have a morphology similar in many, but not all, respects to that of smooth muscle cells in vivo. The cells secrete soluble collagen-like molecules in addition to several proteins of undefined function. Finally, there is an increase in the specific activities of creatine phosphokinase and myokinase associated with increased cell density and the cessation of cell division.

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