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

Takeuchi, Tadayoshi; Fujita, Akikazu; Kushida, Masahiko; Hata, Fumiaki

doi:10.1254/jphs.91.277

Cited by 5 publications

(5 citation statements)

References 33 publications

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“…Studies in longitudinal smooth muscle strips of the rat proximal and distal colon suggest that activation of muscarinic receptors by Ach produces significant contractile response partly due to Ca 2ϩ sensitization via activation of PKC (Takeuchi et al, 2004). The present experiments demonstrated that exposure of GPISMLL to 10 Gy ␥-radiation enhanced Ach contraction.…”

Section: Downloaded Fromsupporting

confidence: 57%

α- and ϵ-Protein Kinase C Activity during Smooth Muscle Cell Apoptosis in Response to γ-Radiation

Claro¹,

Kanashiro²,

Oshiro³

et al. 2007

J Pharmacol Exp Ther

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The use of ␥-radiation in treatment of pelvic cancer is associated with injury of healthy surrounding tissues and disorders of intestinal motility; however, the cellular mechanisms involved are unclear. We tested the hypothesis that exposure of visceral smooth muscle cells (SMCs) to ␥-radiation induces apoptosis via activation of specific protein kinase C (PKC) isoforms. Cultured SMCs and slices from guinea pig ileum smooth muscle longitudinal layer (GPISMLL) were exposed to 10 to 50 Gy. Flow cytometry in ␥-radiated SMCs showed increased percentage of cells in the sub-G 0 /G 1 phase, a hallmark of apoptosis. ␥-Radiation-induced reduction in cell survival was partially but significantly alleviated with the PKC inhibitors. Sections of ␥-irradiated GPISMLL showed DNA fragmentation and apoptotic bodies analyzed by the terminal deoxynucleotidyl transferase dUTP nick-end labeling method, whereas the plasma and nuclear membranes were preserved. Confocal microscopy in ␥-radiated SMCs labeled with annexin V-fluorescein showed an increase in apoptotic cells and phosphatidylserine externalization. Contraction of GPISMLL strips in response to KCl and acetylcholine was reduced in tissues exposed to 30 and 50 Gy. ␥-Radiation of GPISMLL caused an increase in PKC activity in the particulate fraction, a decrease in the cytosolic fraction, and increased particulate/cytosolic PKC activity ratio. Western blot analysis revealed significant amounts of ␣-and -PKC in the cytosolic fraction of control GPISMLL. ␥-Radiation caused an increase in the amount of ␣-and -PKC in the particulate fraction and a decrease in the cytosolic fraction. Data suggest that ␥-radiation induces apoptosis, growth arrest, and contractile dysfunction in visceral SMCs of GPISMLL via activation and translocation of ␣-and -PKC isoforms.

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Section: Downloaded Fromsupporting

confidence: 57%

α- and ϵ-Protein Kinase C Activity during Smooth Muscle Cell Apoptosis in Response to γ-Radiation

Claro¹,

Kanashiro²,

Oshiro³

et al. 2007

J Pharmacol Exp Ther

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“…Isometric tension was measured with a force displacement transducer (AE801, SensoNor, Horten, Norway) and recorded with a recorder (LR4110, Yokogawa, Japan) with a preamplifier (EF601G, Nihon Koden, Japan). In experiments using the membrane-permeabilize preparations, the strips were permeabilized by treatment with α-toxin (167 μg/ml) for 30 min in a relaxing solution containing 111 mM potassium-methanesulfonic acid, 4 mM adenosine triphosphate (ATP)-2Na, 4 mM Mg-methanesulfonic acid, 4 mM [ethylenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA), 20 mM Tris-maleic acid (pH 6.8), and 5 mM phosphocreatine [41]. After equilibration for 10 min in the relaxing solution, responses of the permeabilized muscle to 3 μM Ca 2+ at 10-min intervals were recorded.…”

Section: Measurement Of Contraction In Membrane-permeabilized Preparamentioning

confidence: 99%

“…Four micromolar EGTA was used to clamp free Ca 2+ concentrations, and an appropriate amount of Ca-methanesulfonic acid (0.1 M) was added to give the desired concentration of free Ca 2+ [21]. Concentrations of ATP and phosphocreatine in the relaxing and activating solutions were expressed as total ATP and total phosphocreatine concentrations, respectively [41].…”

Section: Measurement Of Contraction In Membrane-permeabilized Preparamentioning

confidence: 99%

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

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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.

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“…We have also shown that ATP synthesized from ADP and PC by CK is necessary for phasic contraction of the permeabilized smooth muscle of rat proximal colon (7) and that newly synthesized ATP is utilized as substrate for myosin ATPase (8). However, these studies on the role of CK have been mainly carried out by using the "phasic type" smooth muscle.…”

Section: +mentioning

confidence: 99%

Essential Role of ATP Synthesized by Creatine Kinase in Contraction of α-Toxin Permeabilized Preparations of Tonic Type Smooth Muscle

et al. 2003

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Abstract. The role of ATP newly synthesized from ADP and phosphocreatine (PC) by creatine kinase (CK) in the contraction of tonic type smooth muscle, rat femoral artery was studied, since its necessity for phasic type smooth muscle was previously shown. In a-toxin-permeabilized preparations obtained from rat femoral artery, Ca 2+ induced a tonic type contraction in the presence of ATP and PC. Omission of PC inhibited significantly the contraction. Treatment of the preparations with 2,4-dinitrofluorobenzene, an inhibitor of CK, also inhibited the contraction. In the presence of ADP and PC, Ca 2+ also induced the contraction to a level comparable to that in the presence of ATP and PC. The extent of phosphorylated myosin light chain was fairly consistent with that of Ca 2+-induced contraction under all experimental conditions planned above. These results suggest that ATP newly synthesized by CK essentially participates in the whole of the contraction in tonic type smooth muscle, although it participates only in a rapid phasic contraction in phasic type muscle as previously shown.

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

Cited by 5 publications

References 33 publications

α- and ϵ-Protein Kinase C Activity during Smooth Muscle Cell Apoptosis in Response to γ-Radiation

α- and ϵ-Protein Kinase C Activity during Smooth Muscle Cell Apoptosis in Response to γ-Radiation

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

Essential Role of ATP Synthesized by Creatine Kinase in Contraction of α-Toxin Permeabilized Preparations of Tonic Type Smooth Muscle

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