The effects of ATP and α,β‐methylene‐ATP on cytosolic Ca<sup>2+</sup> level and force in rat isolated aorta

Kitajima, Satoshi; Ozaki, Hiroshi; Karaki, Hideaki

doi:10.1111/j.1476-5381.1993.tb13803.x

Cited by 18 publications

(11 citation statements)

References 25 publications

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“…The latter observations support the view that the increase in IP3 content elicited by 1 mM ATP might not be sufficient to elicit the release of Ca2+ from internal source, whereas it was sufficient when the arteries were exposed to 3 mm ATP. The above data are in accordance with those reported by different authors within either isolated aorta or aortic smooth muscle cells of the rat (Nambi, Hsiao-Ling & Nambi, 1990;Kitajima, Ozaki & Karaki, 1993). However, the present results contrast with those in rat portal vein showing that ATP released Ca2+ from intracellular stores by a mechanism that involved Ca2+ entry (Pacaud, Gregoire & Loirand, 1994).…”

Section: Discussionsupporting

confidence: 93%

Calcium handling and purinoceptor subtypes involved in ATP‐induced contraction in rat small mesenteric arteries.

Lagaud

Stoclet

Andriantsitohaina

1996

The Journal of Physiology

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1. The relationship between the stimulation of ATP receptors, the increase in intracellular free calcium concentration ([Ca2+]1; measured using the fluorescent indicator fura-2), contraction and the subtypes of purinoceptors involved were investigated in the small mesenteric artery of the rat. 7. The results suggest that low concentrations of ATP activate P2x-purinoceptors and produce an influx of calcium through both voltage-dependent calcium channels sensitive to nitrendipine and through receptor-operated calcium channels sensitive to SK&F 96365.High concentrations of ATP activate P2Y-purinoceptors which promote firstly a nitrendipine-sensitive calcium influx via a PTX-sensitive G protein and secondly a release of Ca2P from an internal source via the production of 1P3.ATP is an extracellular messenger which acts as a neuro-nervous system of different blood vessels, ATP is involved transmitter or co-transmitter in the central and peripheral in the non-adrenergic, non-cholinergic component of the nervous systems

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Section: Discussionsupporting

confidence: 93%

Calcium handling and purinoceptor subtypes involved in ATP‐induced contraction in rat small mesenteric arteries.

Lagaud

Stoclet

Andriantsitohaina

1996

The Journal of Physiology

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“…rat aorta and large mesenteric arteries, there is a reduced sensitivity of contractions to α,β-meATP [28, 47]. However, P2X 1 receptor immunoreactivity is detected in these vessels (albeit at somewhat reduced levels, as found in this study), and α,β-meATP has been shown to evoke transient rises in intracellular calcium with an EC 50 of <1 µ M from acutely dissociated aortic smooth muscle [60]. In addition, transient P2X 1 receptor-like currents have been recorded from large mesenteric artery cells [Gitterman and Evans, unpubl.…”

Section: Discussionmentioning

confidence: 45%

P2X Receptor Immunoreactivity in Different Arteries from the Femoral, Pulmonary, Cerebral, Coronary and Renal Circulations

Lewis

Evans²

2001

J Vasc Res

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The expression of the seven P2X receptor subunits (P2X_1–7) in the rat vascular system was determined using subtype-selective antibodies. Arteries of different sizes (from arterioles to conduit vessels) from a range of vascular beds were used to give an overview of receptor expression. P2X₁ receptor immunoreactivity was detected in the smooth muscle layer of arteries. The relative level of P2X₁ receptor immunoreactivity was dependent on the size of the artery and the vascular bed; expression was highest in small and medium arteries. P2X₄ receptors were detected in all arteries; once again, the relative level of expression was dependent on the size of the artery and the vascular bed. P2X₅ receptor immunoreactivity was barely detectable in most arteries studied. P2X₇ receptor immunoreactivity was generally punctate and associated with the outer adventitial layer. Immunoreactivity for P2X₂, P2X₃ and P2X₆ receptors was not detected in arteries. These results demonstrate that arteries express multiple P2X receptor subunits and that there is a heterogeneity in the level of expression. The properties of artery P2X receptors correspond to homomeric P2X₁ receptors, and the function of P2X₄ and P2X₅ receptor subunits in arteries is unclear.

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“…Ths type of dissociation may be due to the Ca2" sensitzing effect of neurotransmitters (Karaki, 1989). Furthermore, it has been shown that the initial transient increase in the fura-2 signal is not always coupled to contraction (Sakata et al, 1989;Kitajima et al, 1993). This type of dissociation may be due to the 'non-contractile' Ca2+ compartment.…”

Section: Discussionmentioning

confidence: 99%

Calcium compartments in vascular smooth muscle cells as detected by aequorin signal

Abe

Mitsui

Karaki

et al. 1995

British J Pharmacology

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2 A noradrenaline (10 pM)-induced sustained contraction was associated with a sustained increase in the fura-PE3 signal, or a transient increase followed by small sustained increase in the aequorin signal. A high K+-induced contraction was associated with a sustained increase in both the fura-PE3 and aequorin signals. 3 A second application of noradrenaline or high K+ induced reproducible contractions and fura-PE3 signals. In contrast, the aequorin signal resulting from a second application of noradrenaline or high K+ was much smaller than the first signal. 4 Following a 13 h but not a 3 h resting period, the aequorin signal stimulated by noradrenaline or high K+ recovered, without any change in the contractile response.5 In Ca2"-free solution, high K+ was ineffective, whereas noradrenaline induced only a small aequorin signal and contraction compared to those obtained in the presence of external Ca2". After the addition of Ca2", the first application of noradrenaline induced a large aequorin signal and a large contraction, although a second application induced a much smaller aequorin signal accompanied by a large contraction.6 These results suggest that high K+ and noradrenaline increase Ca2" in at least two cytosolic compartments; a compartment that is coupled to the contractile mechanism ('contractile' Ca2+ compartment; major portion of cytoplasm containing contractile elements) and a compartment that is not coupled to contractile mechanisms ('non-contractile' Ca2+ compartment; small sub-membrane area that does not contain contractile elements). On stimulation, the Ca2+ level in the 'contractile' compartment may increase to a level high enough to stimulate myosin light chain kinase but not so high as to consume aequorin rapidly. In contrast, the Ca2+ level in the 'non-contractile' compartment may increase so greatly that aequorin in this compartment is rapidly consumed. These two compartments may be separated by a diffusion barrier and, during a resting period, aequorin may slowly diffuse from the 'contractile' compartment to the 'non-contractile' compartment and thus restore the full aequorin signal. An increase in Ca2+ in the 'non-contractile' compartment seems to be dependent mainly on Ca2+ influx and partly on Ca2+ release.

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The effects of ATP and α,β‐methylene‐ATP on cytosolic Ca²⁺ level and force in rat isolated aorta

Abstract: 1 The effects of a non-selective P2-receptor agonist ATP and a selective P2x-receptor agonist a,pmethylene-ATP on intracellular free Ca2+ level ([Ca2+]

Cited by 18 publications

References 25 publications

Calcium handling and purinoceptor subtypes involved in ATP‐induced contraction in rat small mesenteric arteries.

Calcium handling and purinoceptor subtypes involved in ATP‐induced contraction in rat small mesenteric arteries.

P2X Receptor Immunoreactivity in Different Arteries from the Femoral, Pulmonary, Cerebral, Coronary and Renal Circulations

Calcium compartments in vascular smooth muscle cells as detected by aequorin signal

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The effects of ATP and α,β‐methylene‐ATP on cytosolic Ca2+ level and force in rat isolated aorta

Abstract: 1 The effects of a non-selective P2-receptor agonist ATP and a selective P2x-receptor agonist a,pmethylene-ATP on intracellular free Ca2+ level ([Ca2+]

Cited by 18 publications

References 25 publications

Calcium handling and purinoceptor subtypes involved in ATP‐induced contraction in rat small mesenteric arteries.

Calcium handling and purinoceptor subtypes involved in ATP‐induced contraction in rat small mesenteric arteries.

P2X Receptor Immunoreactivity in Different Arteries from the Femoral, Pulmonary, Cerebral, Coronary and Renal Circulations

Calcium compartments in vascular smooth muscle cells as detected by aequorin signal

Contact Info

Product

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The effects of ATP and α,β‐methylene‐ATP on cytosolic Ca²⁺ level and force in rat isolated aorta