| 1. |
- Lindqvist, Anders, et al.
(författare)
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Inhibition of calcium entry preserves contractility of arterial smooth muscle in culture
- 1997
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Ingår i: Journal of Vascular Research. - 1423-0135. ; 34:2, s. 103-108
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Tidskriftsartikel (refereegranskat)abstract
- The addition of the growth stimulator fetal calf serum (FCS, 10%) to rings of rat tail artery causes an increase in [Ca2+]i, accompanied by contraction. This response was inhibited by the calcium entry blocker verapamil (1 microM). To investigate the effect of Ca2+ entry blockade on growth and contractility, rings of rat tail artery were cultured for 4 days in medium with or without FCS and then mounted for tension registration and stimulated with noradrenaline (NA) or high-K+ solution. In cultured rings growth was quantitated by [3H]-thymidine incorporation and increase in protein contents. FCS in the medium stimulated DNA synthesis by about 2-fold and increased protein contents by about 70%. The growth-stimulated cultured rings developed less force than freshly prepared rings (2.2 +/- 0.3 vs. 8.3 +/- 1.0 mN/mm). The addition of 1 microM verapamil to the medium during culture increased maximal NA-evoked force to 5.0 +/- 0.4 mN/mm but had no effect on the increases in DNA synthesis and protein contents. Force developed by growth-arrested rings, cultured in the absence of FCS, was not different from that of freshly prepared rings (7.2 +/- 0.6 mM/mm). Verapamil did not affect maximal force in these rings. Similar responses were seen when contraction was elicited by high-K+ solution. We conclude that verapamil, present during culture, preserves contractility of arterial smooth muscle, and that this effect is not parallel to inhibition of growth.
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| 2. |
- Lindqvist, Anders, et al.
(författare)
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Long-term effects of Ca(2+) on structure and contractility of vascular smooth muscle
- 1999
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Ingår i: American Journal of Physiology: Cell Physiology. - 1522-1563. ; 277:1, s. 64-73
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Tidskriftsartikel (refereegranskat)abstract
- Culture of dispersed smooth muscle cells is known to cause rapid modulation from the contractile to the synthetic cellular phenotype. However, organ culture of smooth muscle tissue, with maintained extracellular matrix and cell-cell contacts, may facilitate maintenance of the contractile phenotype. To test the influence of culture conditions, structural, functional, and biochemical properties of rat tail arterial rings were investigated after culture. Rings were cultured for 4 days in the absence and presence of 10% FCS and then mounted for physiological experiments. Intracellular Ca(2+) concentration ([Ca(2+)](i)) after stimulation with norepinephrine was similar in rings cultured with and without FCS, whereas force development after FCS was decreased by >50%. The difference persisted after permeabilization with beta-escin. These effects were associated with the presence of vasoconstrictors in FCS and were dissociated from its growth-stimulatory action. FCS treatment increased lactate production but did not affect ATP, ADP, or AMP contents. The contents of actin and myosin were decreased by culture but similar for all culture conditions. There was no effect of FCS on calponin contents or myosin SM1/SM2 isoform composition, nor was there any appearance of nonmuscle myosin. FCS-stimulated rings showed evidence of cell degeneration not found after culture without FCS or with FCS + verapamil (1 microM) to lower [Ca(2+)](i). The decreased force-generating ability after culture with FCS is thus associated with increased [Ca(2+)](i) during culture and not primarily caused by growth-associated modulation of cells from the contractile to the synthetic phenotype.
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| 3. |
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| 4. |
- Nilsson, Bengt-Olof, et al.
(författare)
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Effects of polyamine synthesis inhibition on polyamines, growth and mechanical properties in hypertrophic rat urinary bladder
- 1998
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Ingår i: Pharmacology and Toxicology. - 1600-0773. ; 82:6, s. 287-294
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Tidskriftsartikel (refereegranskat)abstract
- The polyamines putrescine, spermidine and spermine, are ubiquitous intracellular metabolites associated with growth and protein synthesis. In this study effects of polyamine synthesis inhibition on bladder growth, polyamine levels and mechanical properties were investigated in rat urinary bladder subjected to partial outflow obstruction that causes bladder hypertrophy. The S-adenosyl methionine decarboxylase inhibitor CGP-48664 (5 and 20 mg kg-1) was administered alone or in combination with the ornithine decarboxylase inhibitor DFMO (500 mg kg-1), starting one day before creation of partial outflow obstruction and then daily for 7 days. The bladder muscle level of putrescine was increased 38 times and that of spermine reduced by 4 times while spermidine was unchanged after treatment with CGP-48664 (20 mg kg-1). The increase in putrescine was abolished in animals receiving CGP-48664 in combination with DFMO. Treatment with polyamine synthesis inhibitors could not prevent or reduce the hypertrophy of the bladder as judged by bladder wet weight and protein contents. The effects on polyamine quantities were not associated with changes in Ca(2+)-force relationship or in agonist and electrically stimulated force. In summary, treatment of rats with polyamine synthesis inhibitors resulted in changes in polyamine levels in the growing urinary bladder but did not affect growth or mechanical properties.
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| 5. |
- Westerberg, Göran, et al.
(författare)
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Labelling of polysaccharides using [11C]cyanogen bromide : In vivo and in vitro evaluation of 11C-hyaluronan uptake kinetics
- 1995
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Ingår i: Nuclear Medicine and Biology. - 0969-8051 .- 1872-9614. ; 22:2, s. 251-256
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Tidskriftsartikel (refereegranskat)abstract
- A method for the 11C-labelling of polysaccharides in high specific radioactivity is described. Dextran and hyaluronan were treated with [11C]cyanogen bromide in aqueous solution at pH 11.5 to give 30-47% radiochemical yields with higher than 98% radiochemical purity in synthesis times of 24-26 min counted from the end of bombardment. Specific radioactivities at the end of synthesis ranged from 0.12 to 3.1 Ci/mumol. The biodistribution kinetics of [11C]hyaluronan injected intravenously was studied in rats by means of positron emission tomography, showing a rapid and displaceable uptake in liver. Uptake and displacement of [11C]hyaluronan was also demonstrated in cultured rat liver endothelial cells.
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