Origin of Ca2+ Necessary for Carbachol-Induced Contraction in Longitudinal Muscle of the Proximal Colon of Rats

Takeuchi, Tadayoshi; Sumiyoshi, Masahiro; Kitayama, Munenori; Hirayama, Nobue; Fujita, Akikazu; Hata, Fumiaki

doi:10.1254/jjp.87.309

Cited by 12 publications

(5 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1); a slight increase in [Ca 2+ ]i induced a large contraction. This result was consistent with a previous report in the longitudinal muscle of the rat proximal colon [43]. In contrast, we report for the first time that Ca 2+ sensitization does not have a significant role in the sustained contraction induced by the activation of muscarinic receptors in the circular muscle of the rat distal colon.…”

Section: Discussionsupporting

confidence: 94%

A minor role for Ca2+ sensitization in sustained contraction through activation of muscarinic receptor in circular muscle of rat distal colon

Takeuchi

Nakajima

Hata

et al. 2007

Pflugers Arch - Eur J Physiol

Self Cite

View full text Add to dashboard Cite

We previously demonstrated that Ca(2+) sensitization has an essential role for carbachol-induced contraction in the longitudinal muscle of the rat distal colon. In the present study, we extended these studies to clarify the role of Ca(2+) sensitization in contraction induced by the activation of muscarinic receptors in the circular muscle of the rat distal colon. Carbachol induced a rapid phasic contraction followed by a sustained contraction that was significantly lower than the phasic and was superimposed with the rhythmic contractions. The extent of increase in intracellular Ca(2+) concentration that was measured simultaneously with tension recording was dissociated from the phasic contraction, whereas it exhibited to a similar extent as sustained contraction. In alpha-toxin-permeabilized preparations, Ca(2+) induced contraction comprising a rapid phasic and a subsequent low sustained component. After Ca(2+)-induced sustained contraction reached a constant level, guanosine triphosphate (GTP) addition resulted in the enhancement of contractile force in a concentration-dependent manner. Carbachol in the presence of GTP caused a further minimal increase in tension (Ca(2+) sensitization). Chelerythrine, a protein kinase C (PKC) inhibitor, inhibited carbachol-induced Ca(2+) sensitization but not GTP-induced Ca(2+) sensitization. In contrast, Y-27632, a Rho kinase inhibitor, inhibited GTP-induced Ca(2+) sensitization but not that induced by carbachol. Phorbol 12,13-dibutyrate, a PKC activator, increased the sustained contraction. These results suggest that the activation of muscarinic receptor with carbachol induces Ca(2+) sensitization via activation of PKC, but this action is minor in the circular muscle of the rat distal colon as a result of limited coupling between muscarinic receptors and Ca(2+) sensitization via the PKC pathway.

show abstract

Section: Discussionsupporting

confidence: 94%

A minor role for Ca2+ sensitization in sustained contraction through activation of muscarinic receptor in circular muscle of rat distal colon

Takeuchi

Nakajima

Hata

et al. 2007

Pflugers Arch - Eur J Physiol

Self Cite

View full text Add to dashboard Cite

show abstract

“…The proximal colon was removed and placed into Tyrode solution containing 127 mM NaCl, 2.7 mM KCl, 1.8 mM CaCl 2 , 1.05 mM MgCl 2 , 11.9 mM NaHCO 3 , 0.4 mM NaH 2 PO 4 and 5.6 mM glucose. Longitudinal muscles of rat proximal colon were prepared as described previously (18). Small strips (0.1 -0.2´1 mm) of longitudinal muscle were prepared under an inverted microscope.…”

Section: Methodsmentioning

confidence: 99%

The Site Where Newly Synthesized ATP Is Necessary for Tension Development in α-Toxin Permeabilized Preparations of Rat Proximal Colon

et al. 2003

Self Cite

View full text Add to dashboard Cite

Since it was suggested in our previous study that ATP newly synthesized from ADP and phosphocreatine (PCr) by creatine kinase had an important role in Ca2+-induced phasic contraction in alpha-toxin permeabilized smooth muscle of rat proximal colon, we studied the role of newly synthesized ATP on myosin ATPase activity, by assessing a rate of force development as an index of myosin ATPase activity. The alpha-toxin-permeabilized preparations were thiophosphorylated by treatment with ATPgammaS. After the thiophosphorylation, the contraction induced by ATP plus PCr in the absence of Ca2+ reached the maximum at 30 s. When PCr was omitted from the bathing solution, the initial rate of the contraction was significantly slower, while the level of myosin light chain thiophosphorylation remained unchanged. An inhibitor of creatine kinase slowed the initial contractile rate to a rate similar to that induced by ATP alone. ADPbetaS had no effect on ATP plus PCr-induced contraction, suggesting that accumulation of ADP does not affect the initial rate of the contraction. PCr alone did not contract the thiophosphorylated-preparations. However, in the presence of ADP, PCr induced contraction at the initial rate which was slower than that induced by ATP plus PCr. These results indicate that newly synthesized ATP together with preexisting ATP is utilized as a substrate for myosin ATPase.

show abstract

“…Influx of extracellular Ca 2+ is mainly mediated by VOCCs, ROCCs and SOCCs. The study of Takeuchi et al [32] has shown that the source of Ca 2+ in smooth muscle cells in the guinea pig proximal colon is mainly dependent on VOCCs. It is postulated that the source of activator Ca 2+ for the contractile response varies among different regions of the gastrointestinal tract and the animals used.…”

Section: +mentioning

confidence: 99%

Sources of calcium in agonist-induced contraction of rat distal colon smooth muscle in vitro

Zhou

De-hu²,

Pan³

et al. 2008

WJG

View full text Add to dashboard Cite

AIM:To study the origin of calcium necessary for agonist-induced contraction of the distal colon in rats. METHODS:The change in intracel lular calcium concentration ([Ca 2+ ]i) evoked by elevating external Ca 2+ was detected by fura 2/AM fluorescence. Contractile activity was measured with a force displacement transducer. Tension was continuously monitored and recorded using a Powerlab 4/25T data acquisition system with an ML110 bridge bioelectric physiographic amplifier. RESULTS:Store depletion induced Ca 2+ influx had an effect on [Ca 2+ ]i. In nominally Ca 2+ -free medium, the sarco-endoplasmic reticulum Ca 2+ -ATPase inhibitor thapsigargin (1 µmol/L) increased [Ca 2+ ]i from 68 to 241 nmol/L, and to 458 (P < 0.01) and 1006 nmol/L (P < 0.01), respectively, when 1.5 mmol/L and 3.0 mmol/L extracellular Ca 2+ was reintroduced. Furthermore, the change in [Ca 2+ ]i was observed with verapamil (5 µmol/L), La 3+ (1 mmol/L) or KCl (40 mmol/L) in the bathing solution. These channels were sensitive to La 3+ (P < 0.01), insensitive to verapamil, and voltage independent. In isolated distal colons we found that in normal Krebs solution, contraction induced by acetylcholine (ACh) was partially inhibited by verapamil, and the inhibitory rate was 41% (P < 0.05). On the other hand, in Ca 2+ -free Krebs solution, ACh induced transient contraction due to Ca 2+ release from the intracellular stores. The transient contraction lasted until the Ca 2+ store was depleted. Restoration of extracellular Ca 2+ in the presence of atropine produced contraction, mainly due to Ca 2+ influx. Such contraction was not inhibited by verapamil, but was decreased by La 3+ (50 µmol/L) from 0.96 to 0.72 g (P < 0.01). CONCLUSION:The predominant source of activator C a 2 + f o r t h e c o n t ra c t i l e r e s p o n s e t o a g o n i s t i s extracellular Ca 2+ , and intracellular Ca 2+ has little role to play in mediating excitation-contraction coupling by agonists in rat distal colon smooth muscle in vitro . The influx of extracellular Ca 2+ is mainly mediated through voltage-, receptor-and store-operated Ca 2+ channels, which can be used as an alternative to develop new drugs targeted on the dysfunction of digestive tract motility.

show abstract

Origin of Ca2+ Necessary for Carbachol-Induced Contraction in Longitudinal Muscle of the Proximal Colon of Rats

Cited by 12 publications

References 26 publications

A minor role for Ca2+ sensitization in sustained contraction through activation of muscarinic receptor in circular muscle of rat distal colon

A minor role for Ca2+ sensitization in sustained contraction through activation of muscarinic receptor in circular muscle of rat distal colon

The Site Where Newly Synthesized ATP Is Necessary for Tension Development in α-Toxin Permeabilized Preparations of Rat Proximal Colon

Sources of calcium in agonist-induced contraction of rat distal colon smooth muscle in vitro

Contact Info

Product

Resources

About