Manganese ions penetrate via L-type Ca2+ channels and induce contraction in high-K+ medium in ileal longitudinal muscle of guinea-pig

Nasu, Tetsuyuki; Murase, Hirofumi; Shibata, Hiroshi

doi:10.1016/0306-3623(94)00186-q

Cited by 17 publications

(8 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has also been reported that micromolar concentrations of Mn 2+ can cause a transient contractile response through the release of acetylcholine (42). Mn 2+ has also been shown to enter cells via voltage-operated L-type Ca 2+ channels and directly induce contractions at millimolar concentrations in a Ca 2+ -free, high-K + medium (43)(44)(45). These studies have shown that Mn 2+ inhibits Ca 2+ influx in a concentrationdependent manner; however, the Mn 2+ concentrations (nanomolar range) used in this study are far lower than the concentrations used in the studies described above.…”

Section: Discussionmentioning

confidence: 97%

Monitoring dynamic alterations in calcium homeostasis by T₁‐mapping manganese‐enhanced MRI (MEMRI) in the early stage of small intestinal ischemia–reperfusion injury

et al. 2015

View full text Add to dashboard Cite

Manganese-enhanced MRI studies have proven to be useful in monitoring physiological activities associated with calcium ions (Ca(2+)) due to the paramagnetic property of the manganese ion (Mn(2+)), which makes it an excellent probe of Ca(2+) . In this study, we developed a method in which a Mn(2+)-enhanced T1 -map MRI could enable the monitoring of Ca(2+) influx during the early stages of intestinal ischemia-reperfusion (I/R) injury. The Mn(2+) infusion protocol was optimized by obtaining dose-dependent and time-course wash-out curves using a Mn(2+)-enhanced T1-map MRI of rabbit abdomens following an intravenous infusion of 50 mmol/l MnCl2 (5-10 nmol/g body weight (BW)). In the rabbit model of intestinal I/R injury, T1 values were derived from the T1 maps in the intestinal wall region and revealed a relationship between the dose of the infused MnCl2 and the intestinal wall relaxation time. Significant Mn(2+) clearance was also observed over time in control animals after the infusion of Mn(2+) at a dose of 10 nmol/g BW. This technique was also shown to be sensitive enough to monitor variations in calcium ion homeostasis in vivo after small intestinal I/R injury. The T1 values of the intestinal I/R group were significantly lower (P < 0.05) than that of the control group at 5, 10, and 15 min after Mn(2+) infusion. Our data suggest that MnCl2 has the potential to be an MRI contrast agent that can be effectively used to monitor changes in intracellular Ca(2+) homeostasis during the early stages of intestinal I/R injury.

show abstract

Section: Discussionmentioning

confidence: 97%

Monitoring dynamic alterations in calcium homeostasis by T₁‐mapping manganese‐enhanced MRI (MEMRI) in the early stage of small intestinal ischemia–reperfusion injury

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Mn 2+ inhibited smooth muscle contraction by blocking Ca 2+ influx [ 18 ]; the inhibition could be overcome by high extracellular Ca 2+ concentrations at millimolar concentrations [ 19 ]. Mn 2+ can cause a transient contractile response through the release of acetylcholine [ 20 ] or directly induce contractions via voltage-operated L-type Ca 2+ channels at millimolar concentrations [ 21 – 23 ]. In present study, the Mn 2+ concentrations are at nanomolar range and are far lower than the concentrations described above.…”

Section: Discussionmentioning

confidence: 99%

A New Approach Using Manganese-Enhanced MRI to Diagnose Acute Mesenteric Ischemia in a Rabbit Model: Initial Experience

Zhao

Cheng

Kuang

et al. 2015

BioMed Research International

View full text Add to dashboard Cite

Purpose. Manganese-enhanced MRI (MEMRI) has been applied to a wide range of biological and disease research. The purpose of the study was to use MEMRI to diagnose the acute mesenteric ischemia (AMI). Methods. The institutional experimental animal ethics committee approved this study. To optimize the dose of Mn2+ infusion, a dose-dependent curve was obtained using Mn2+-enhanced T 1 map MRI by an intravenous infusion 2.5–20 nmol/g body weight (BW) of 50 nmol/L MnCl2. The eighteen animals were divided into control, sham-operated, and AMI groups. AMI models were performed by ligating the superior mesenteric artery (SMA). T 1 values were measured on T 1 maps in regions of the small intestinal wall and relaxation rate (ΔR 1) was calculated. Results. A nonlinear relationship between infused MnCl2 solution dose and increase in small intestinal wall ΔR 1 was observed. Control animal exhibited significant Mn2+ clearance over time at the dose of 15 nmol/g BW. In the AMI model, ΔR 1 values (0.95 ± 0.13) in the small intestinal wall were significantly lower than in control group (2.05 ± 0.19) after Mn2+ infusion (P < 0.01). Conclusion. The data suggest that MEMRI shows potential as a diagnostic technique that is directly sensitive to the poor or absent perfusion in AMI.

show abstract

“…First, external Ca 2+ is necessary to induce the ileal response to Cu 2+ . However, external Ca 2+ is not necessary to induce a contractile response to Mn 2+ , although the existence of a high concentration of K + is necessary (Nasu, Murase & Shibata, 1995). Secondly, Ca 2+ must be mobilized by Cu 2+ to initiate the contraction from external fluid.…”

Section: Discussionmentioning

confidence: 99%

“…Secondly, Ca 2+ must be mobilized by Cu 2+ to initiate the contraction from external fluid. In comparison, Mn 2+ penetrates through L‐type Ca 2+ ‐channels in the ileal cell membrane in a state of prolonged depolarization, induced by a high K + concentration and activates the contractile elements (Nasu et al. , 1995).…”

Section: Discussionmentioning

confidence: 99%

Long‐lasting contractile action and the inhibitory action of cupric ions on ileal longitudinal muscle

Miyazaki

Nasu

2004

Auton Autocoid Pharmacol

Self Cite

View full text Add to dashboard Cite

Cupric ions (Cu(2+)), at concentrations above 0.03 mM, induced a progressive increase in the tonic contraction of guinea-pig ileal longitudinal muscle. Maximal contraction of 0.1 mM Cu(2+) attained a level above that of the 60-mM K(+)-induced tonic response, within 20 min of application. The tension induced by Cu(2+) persisted for more than several hours. Tetrodotoxin (3 x 10(-6) M) had no effect on the contraction induced by 0.1 mM Cu(2+). After incubation in a Ca(2+)-free medium, the ileal response to 0.1 mM Cu(2+) was lost. Nifedipine, a L-type Ca(2+) channel blocker, dose-dependently inhibited contractions induced by Cu(2+). As the duration of the first application of 0.1 mM Cu(2+) increased above 30 min, after washing with normal medium, the contractile response to a second application of 0.1 mM Cu(2+) decreased gradually. After 150 min of the first application of 0.1 mM Cu(2+), a second application of Cu(2+) could not evoke any contraction. After the application of 0.1 mM Cu(2+) for 150 min, when muscles were washed with a medium containing 1 mM EDTA, the response to 0.1 mM Cu(2+) returned to a greater extent in the normal Ca(2+) medium. In conclusion, Cu(2+) (0.1 mM) induced a maximal ileal tension above that of the K-induced tonic response within 20 min. The ileal contraction to Cu(2+) persisted for more than several hours and depended on extracellular Ca(2+) concentrations. It is possible that a part of Cu(2+), bound to a EDTA-inaccessible site, also has a tension inhibitory effect.

show abstract

Manganese ions penetrate via L-type Ca2+ channels and induce contraction in high-K+ medium in ileal longitudinal muscle of guinea-pig

Cited by 17 publications

References 19 publications

Monitoring dynamic alterations in calcium homeostasis by T₁‐mapping manganese‐enhanced MRI (MEMRI) in the early stage of small intestinal ischemia–reperfusion injury

Monitoring dynamic alterations in calcium homeostasis by T₁‐mapping manganese‐enhanced MRI (MEMRI) in the early stage of small intestinal ischemia–reperfusion injury

A New Approach Using Manganese-Enhanced MRI to Diagnose Acute Mesenteric Ischemia in a Rabbit Model: Initial Experience

Long‐lasting contractile action and the inhibitory action of cupric ions on ileal longitudinal muscle

Contact Info

Product

Resources

About

Manganese ions penetrate via L-type Ca2+ channels and induce contraction in high-K+ medium in ileal longitudinal muscle of guinea-pig

Cited by 17 publications

References 19 publications

Monitoring dynamic alterations in calcium homeostasis by T1‐mapping manganese‐enhanced MRI (MEMRI) in the early stage of small intestinal ischemia–reperfusion injury

Monitoring dynamic alterations in calcium homeostasis by T1‐mapping manganese‐enhanced MRI (MEMRI) in the early stage of small intestinal ischemia–reperfusion injury

A New Approach Using Manganese-Enhanced MRI to Diagnose Acute Mesenteric Ischemia in a Rabbit Model: Initial Experience

Long‐lasting contractile action and the inhibitory action of cupric ions on ileal longitudinal muscle

Contact Info

Product

Resources

About

Monitoring dynamic alterations in calcium homeostasis by T₁‐mapping manganese‐enhanced MRI (MEMRI) in the early stage of small intestinal ischemia–reperfusion injury

Monitoring dynamic alterations in calcium homeostasis by T₁‐mapping manganese‐enhanced MRI (MEMRI) in the early stage of small intestinal ischemia–reperfusion injury