scholarly journals Electric field-directed cell shape changes, displacement, and cytoskeletal reorganization are calcium dependent.

1988 ◽  
Vol 106 (6) ◽  
pp. 2067-2075 ◽  
Author(s):  
E K Onuma ◽  
S W Hui

C3H/10T1/2 mouse embryo fibroblasts were stimulated by a steady electric field ranging up to 10 V/cm. Some cells elongated and aligned perpendicular to the field direction. A preferential positional shift toward the cathode was observed which was inhibited by the calcium channel blocker D-600 and the calmodulin antagonist trifluoperazine. Rhodaminephalloidin labeling of actin filaments revealed a field-induced disorganization of the stress fiber pattern, which was reduced when stimulation was conducted in calcium-depleted buffer or in buffer containing calcium antagonist CoCl2, calcium channel blocker D-600, or calmodulin antagonist trifluoperazine. Treatment with calcium ionophore A23187 had similar effects, except that the presence of D-600 did not reduce the stress fiber disruption. The calcium-sensitive photoprotein aequorin was used to monitor changes in intracellular-free calcium. Electric stimulation caused an increase of calcium to the micromolar range. This increase was inhibited by calcium-depleted buffer or by CoCl2, and was reduced by D-600. A calcium-dependent mechanism is proposed to explain the observed field-directed cell shape changes, preferential orientation, and displacement.

2003 ◽  
Vol 52 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Shigeki TSUTSUI ◽  
Shin-ichi ITAGAKI ◽  
Seiji KAWAMURA ◽  
Ken-ichi HARADA ◽  
Hideaki KARAKI ◽  
...  

1990 ◽  
Vol 122 (3) ◽  
pp. 403-408
Author(s):  
Ph. Touraine ◽  
P. Birman ◽  
F. Bai-Grenier ◽  
C. Dubray ◽  
F. Peillon ◽  
...  

Abstract In order to investigate whether a calcium channel blocker could modulate the protein kinase C activity in normal and estradiol pretreated rat pituitary, female Wistar rats were treated or not (controls) with ± PN 200-110 (3 mg · kg−1 · day−1, sc) for 8 days or with estradiol cervical implants for 8 or 15 days, alone or in combination with PN 200-110 the last 8 days. Estradiol treatment induced a significant increase in plasma prolactin levels and pituitary weight. PN 200-110 administered to normal rats did not modify these parameters, whereas it reduced the effects of the 15 days estradiol treatment on prolactin levels (53.1 ± 4.9 vs 95.0 ±9.1 μg/l, p<0.0001) and pituitary weight (19.9 ± 0.4 vs 23.0 ± 0.6 mg, p <0.001), to values statistically comparable to those measured after 8 days of estradiol treatment. PN 200-110 alone did not induce any change in protein kinase C activity as compared with controls. In contrast, PN 200-110 treatment significantly counteracted the large increase in soluble activity and the decrease in the particulate one induced by estradiol between day 8 and day 15. We conclude that PN 200-110 opposed the stimulatory effects of chronic in vivo estradiol treatment on plasma prolactin levels and pituitary weight and that this regulation was related to a concomitant modulation of the protein kinase C activity.


2020 ◽  
Vol 16 ◽  
Author(s):  
Seiji Umemoto ◽  
Toshio Ogihara ◽  
Masunori Matsuzaki ◽  
Hiromi Rakugi ◽  
Kazuyuki Shimada ◽  
...  

Background: In the trial known as COPE (Combination Therapy of Hypertension to Prevent Cardiovascular Events) three benidipine (a calcium channel blocker; CCB) regimens were compared. Hypertensive Japanese outpatients aged 40–85 years (n=3,293) who did not achieve the target blood pressure of <140/90 mmHg with benidipine 4 mg/day were treated with the diuretic thiazide (n=1,094) or a β-blocker (n=1,089) or an additional angiotensin receptor blocker (ARB; n=1,110). A significantly higher incidence of hard cardiovascular composite endpoints and of fatal or non-fatal strokes was observed in the benidipine-β-blocker group compared to the benidipine-thiazide group. Objective and Methods: We further evaluated the treatment effects of the three benidipine-based regimens on vascular and renal events in a sub-analysis of the COPE patients. Results: A total of 10 vascular events (0.8 per 1,000 person-years) including one aortic dissection (0.1 per 1,000 person-years) and nine cases of peripheral artery disease (0.8 per 1,000 person-years) were documented, as was a total of seven renal events (0.6 per 1,000 person-years). No significant differences in vascular and renal events were revealed among the three treatment groups: vascular events p=0.92 renal events p=0.16 log-rank test. Conclusions: Blood pressure-lowering therapy with benidipine combined with an ARB, β-blocker, or thiazide was similarly effective in the prevention of vascular and renal events in hypertensive outpatients, although there is no enough these events to compare the difference in the three treatment groups.


2014 ◽  
Vol 9 (3) ◽  
pp. 193-201 ◽  
Author(s):  
Tsuneo Takenaka ◽  
Yoichi Ohno ◽  
Hiromichi Suzuki

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