scholarly journals Characterization of an outward potassium current in canine jejunal circular smooth muscle and its activation by fenamates.

1993 ◽  
Vol 468 (1) ◽  
pp. 297-310 ◽  
Author(s):  
G Farrugia ◽  
J L Rae ◽  
J H Szurszewski
Keyword(s):  
Smooth Muscle ◽  
Potassium Current ◽  
Circular Smooth Muscle ◽  
Outward Potassium Current

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 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.

scholarly journals Pharmacological characterization of 5-HT4 receptors mediating relaxation of canine isolated rectum circular smooth muscle

1999 ◽  
Vol 127 (6) ◽  
pp. 1431-1437 ◽  
Author(s):  
N H Prins ◽  
J F W R Van Haselen ◽  
R A Lefebvre ◽  
M R Briejer ◽  
L M A Akkermans ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Pharmacological Characterization ◽  
Circular Smooth Muscle
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