| 61. |
- Chen, Y, et al.
(författare)
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Increase in insulin-like growth factor I in hypertrophying smooth muscle
- 1994
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Ingår i: American Journal of Physiology - Endocrinology and Metabolism. - 1522-1555. ; 266:2 Pt 1, s. 224-229
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Tidskriftsartikel (refereegranskat)abstract
- The present study focuses on the role of the insulin-like growth factor (IGF) system in the development of smooth muscle hypertrophy. Hypertrophy was initiated by partial ligation of portal vein or urethra in female Sprague-Dawley rats weighing approximately 220 g. Levels of mRNA were analyzed by solution hybridization. Seven days after ligation, the wet weight of the portal vein was increased about threefold and the concentration of IGF-I mRNA was increased fourfold. The bladder wet weight was increased twofold 3 days after ligation and fourfold 10 days after ligation. IGF-I mRNA in the bladder was elevated 3-fold after 3 days and 2.5-fold after 10 days, whereas IGF binding protein 2 mRNA was increased approximately 2-fold after 3 days and 5-fold after 10 days. IGF-I receptor mRNA in the hypertrophying bladder remained unchanged. Increased levels of IGF-I were demonstrated with immunohistochemistry in both hypertrophying portal vein and urinary bladder. The results show a specific increase in IGF-I mRNA as well as an increased IGF-I immunoreactivity during hypertrophy of smooth muscle, which suggests that the local IGF-system may play a role in smooth muscle hypertrophy.
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| 62. |
- De Basso, Rachel, et al.
(författare)
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Increased carotid plaque burden in men with the fibrillin-1 2/3 genotype
- 2014
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Ingår i: Clinical and Experimental Pharmacology and Physiology. - : Wiley. - 1440-1681 .- 0305-1870. ; 41:9, s. 637-642
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Tidskriftsartikel (refereegranskat)abstract
- Fibrillin-1 (FBN1) is an important constituent of the vascular wall and earlier studies have indicated an effect of the FBN1 2/3 genotype on blood pressure as well as aortic stiffness in men. The aim of the present study was to determine whether the FBN1 2/3 genotype was associated with the presence of carotid plaque and incident cardiovascular morbidity and mortality in middle-aged subjects. The FBN1 genotype was characterized in 5765 subjects (2424 men, 3341 women; age 45-69years) recruited from the Malmo Diet and Cancer Study Cardiovascular Cohort, Sweden. Plaque occurrence and intima-media thickness (IMT) of the carotid artery were assessed by ultrasound. The incidence of first cardiovascular events (myocardial infarction and stroke) and cause-specific mortality were monitored over a mean follow-up period of 13.2years. The most common FBN1 genotypes were 2/2, 2/3 and 2/4, which accounted for 92.2% (n=5317) of subjects. There were no differences between the three genotypes regarding age, blood pressure, glucose, lipids, smoking habits, common carotid artery diameter and intima-media thickness in men and women. The presence of plaque in the carotid artery was higher in men with the 2/3 genotype compared with the 2/2 and 2/4 genotypes (55% vs 46% and 50%, respectively; P=0.007). No similar differences were observed in women. No significant relationship was observed between FBN1 genotypes and the incidence of cardiovascular disease or all-cause mortality. The increased prevalence of plaque in the carotid artery of middle-aged men with the FBN1 2/3 genotype indicates pathological arterial wall remodelling with a more pronounced atherosclerotic burden.
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| 63. |
- Gabrielsson, Johan
(författare)
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Dose-response-time data analysis involving nonlinear dynamics, feedback and delay
- 2014
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 59, s. 36-48
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Tidskriftsartikel (refereegranskat)abstract
- This paper offers dose-response-time data analysis of four different case studies where the pharmacological response (neuronal ACh-release, tail-flick response, locomotor activity, NEFA) was modelled by a biophase-driven turnover model. The analysis uses a mathematical/analytical perspective in which analytic properties of the models involved are exploited in order to address the dual challenge of extracting information from these time-series about (i) the biophase kinetics following different routes of administration and (ii) pharmacodynamic issues such as transduction, saturation, and adaptation, and more specifically, parameter identifiability, such as correct estimation of potency (SD50 or ID50). It is shown how many of these estimates can be obtained by analytical means, giving considerable insight in the dynamics involved. (C) 2014 Elsevier B.V. All rights reserved.
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| 64. |
- Gabrielsson, Johan
(författare)
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Mixture dynamics: Dual action of inhibition and stimulation
- 2013
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 50, s. 215-226
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Tidskriftsartikel (refereegranskat)abstract
- The impact of a drug, or of multiple drugs, on different receptors usually results in a combination of responses. They may be either opposing or reinforcing one another and can lead to complex response versus drug-concentration relations. In this paper, complexity and synergy of multiple drug actions are studied on the basis of four data sets: two involving opposing actions and two resulting from synergistic actions. It is shown that turnover models can be successfully fitted to these data, offer a mechanism for dissecting complex response versus drug-concentration curves, for understanding and quantifying amplification of dual drug actions and elucidate the role of potencies and other parameters related to the different drugs. (C) 2013 Elsevier B.V. All rights reserved.
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| 65. |
- Gennemark, Peter, 1974, et al.
(författare)
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Modeling energy intake by adding homeostatic feedback and drug intervention
- 2015
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Ingår i: Journal of Pharmacokinetics and Pharmacodynamics. - : Springer Science and Business Media LLC. - 1567-567X .- 1573-8744. ; 42:1, s. 79-96
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Tidskriftsartikel (refereegranskat)abstract
- Energy intake (EI) is a pivotal biomarker used in quantification approaches to metabolic disease processes such as obesity, diabetes, and growth disorders. Eating behavior is however under both short-term and long-term control. This control system manifests itself as tolerance and rebound phenomena in EI, when challenged by drug treatment or diet restriction. The paper describes a model with the capability to capture physiological counter-regulatory feedback actions triggered by energy imbalances. This feedback is general as it handles tolerance to both increases and decreases in EI, and works in both acute and chronic settings. A drug mechanism function inhibits (or stimulates) EI. The deviation of EI relative to a reference level (set-point) serves as input to a non-linear appetite control signal which in turn impacts EI in parallel to the drug intervention. Three examples demonstrate the potential usefulness of the model in both acute and chronic dosing situations. The model shifts the predicted concentration-response relationship rightwardly at lower concentrations, in contrast to models that do not handle functional adaptation. A fourth example further shows that the model may qualitatively explain differences in rate and extent of adaptation in observed EI and its concomitants in both rodents and humans.
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| 66. |
- Gomez-Pinilla, Pedro J, et al.
(författare)
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Melatonin restores impaired contractility in aged guinea pig urinary bladder
- 2008
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Ingår i: Journal of Pineal Research. - : Blackwell Publishing Ltd. - 1600-079X .- 0742-3098. ; 44:4, s. 416-425
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Tidskriftsartikel (refereegranskat)abstract
- Urinary bladder disturbances are frequent in the elderly population but the responsible mechanisms are poorly understood. This study evaluates the effects of aging on detrusor myogenic contractile responses and the impact of melatonin treatment. The contractility of bladder strips from adult, aged and melatonin-treated guinea pigs was evaluated by isometric tension recordings. Cytoplasmatic calcium concentration ([Ca2+](i)) was estimated by epifluorescence microscopy of fura-2-loaded isolated detrusor smooth muscle cells, and the levels of protein expression and phosphorylation were quantitated by Western blotting. Aging impairs the contractile response of detrusor strips to cholinergic and purinergic agonists and to membrane depolarization. The impaired contractility correlates with increased [Ca2+](i) in response to the stimuli, suggesting a reduced Ca(2+)sensitivity. Indeed, the agonist-induced contractions in adult strips were sensitive to blockade with Y27362, an inhibitor of Rho kinase (ROCK) and GF109203X, an inhibitor of protein kinase C (PKC), but these inhibitors had negligible effects in aged strips. The reduced Ca2+ sensitivity in aged tissues correlated with lower levels of RhoA, ROCK, PKC and the two effectors CPI-17 and MYPT1, and with the absence of CPI-17 and MYPT1 phosphorylation in response to agonists. Interestingly, melatonin treatment restored impaired contractility via normalization of Ca2+ handling and Ca2+ sensitizations pathways. Moreover, the indoleamine restored age-induced changes in oxidative stress and mitochondrial polarity. These results suggest that melatonin might be a novel therapeutic tool to palliate aging-related urinary bladder contractile impairment.
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| 67. |
- 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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| 68. |
- Löfgren, Mia, et al.
(författare)
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Substrate and product dependence of force and shortening in fast and slow smooth muscle
- 2001
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Ingår i: Journal of General Physiology. - : Rockefeller University Press. - 0022-1295 .- 1540-7748. ; 117:5, s. 407-418
-
Tidskriftsartikel (refereegranskat)abstract
- To explore the molecular mechanisms responsible for the variation in smooth muscle contractile kinetics, the influence of MgATP, MgADP, and inorganic phosphate (P(i)) on force and shortening velocity in thiophosphorylated "fast" (taenia coli: maximal shortening velocity Vmax = 0.11 ML/s) and "slow" (aorta: Vmax = 0.015 ML/s) smooth muscle from the guinea pig were compared. P(i) inhibited active force with minor effects on the V(max). In the taenia coli, 20 mM P(i) inhibited force by 25%. In the aorta, the effect was markedly less (< 10%), suggesting differences between fast and slow smooth muscles in the binding of P(i) or in the relative population of P(i) binding states during cycling. Lowering of MgATP reduced force and V(max). The aorta was less sensitive to reduction in MgATP (Km for Vmax: 80 microM) than the taenia coli (Km for Vmax: 350 microM). Thus, velocity is controlled by steps preceding the ATP binding and cross-bridge dissociation, and a weaker binding of ATP is not responsible for the lower V(max) in the slow muscle. MgADP inhibited force and V(max). Saturating concentrations of ADP did not completely inhibit maximal shortening velocity. The effect of ADP on Vmax was observed at lower concentrations in the aorta compared with the taenia coli, suggesting that the ADP binding to phosphorylated and cycling cross-bridges is stronger in slow compared with fast smooth muscle.
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| 69. |
- Malmqvist, Ulf, et al.
(författare)
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Contractile and cytoskeletal proteins in smooth muscle during hypertrophy and its reversal
- 1991
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Ingår i: American Journal of Physiology: Cell Physiology. - 1522-1563. ; 260:5, s. 1085-1093
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Tidskriftsartikel (refereegranskat)abstract
- Hypertrophy of rat urinary bladder smooth muscle was induced by partial urethral obstruction. Bladder weight increased from 70 to 240 mg after 10 days and to 700 mg after 7 wk. Removal of the obstruction after 10 days caused a regression of bladder weight to 130 mg. The relative volume of smooth muscle in the bladder wall increased during hypertrophy. The concentration of myosin in the smooth muscle cells decreased in 10-day hypertrophied bladders, whereas the concentration of actin was unchanged. The actin-myosin ratio was 2.3 in controls, 3.3 in 10-day obstructed bladders, and 2.9 in 7-wk obstructed bladders. After removal of obstruction, the ratio was normalized. Two isoforms of myosin heavy chains were identified (SM1 and SM2). The relative amount of SM2 decreased during hypertrophy. The relative proportion of actin isoforms (alpha, beta, and gamma) was altered toward more gamma and less alpha. These changes were reversible upon removal of the obstruction. Desmin was the dominating intermediate filament protein. The concentration of desmin and filamin increased in the hypertrophic bladders. The increased desmin-actin and filamin-actin ratios in obstructed bladders were normalized after removal of the obstruction. The results suggest that the turnover of contractile and cytoskeletal proteins is fast and can be regulated in response to changes in the functional demands in smooth muscle.
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| 70. |
- Malmqvist, Ulf, et al.
(författare)
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Contractile properties during development of hypertrophy of the smooth muscle in the rat portal vein
- 1988
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Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 133:1, s. 49-61
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Tidskriftsartikel (refereegranskat)abstract
- Structural and mechanical alterations during hypertrophy of the rat portal vein were investigated. Growth of the vessel was induced by a partial ligature of the vessel causing an increased transmural pressure. Vessel segments from animals kept with ligature for 1, 3, 5 and 7 days, were compared with vessels from sham-operated animals. Maximal active force and vessel cross-sectional area increased with time in the ligated group. On day 7, force and cross-sectional area at the optimal length, were markedly increased in the ligated group (21.1 +/- 1.0 mN, 0.55 +/- 0.04 mm2, n = 9) compared with the control vessels (11.7 +/- 1.0 mN, 0.30 +/- 0.02 mm2, n = 7). Light and electron microscopy of preparations fixed at optimal length showed that the amount of smooth muscle and the cross-sectional area of cell profiles were almost doubled in the ligated group on day 7, consistent with hypertrophy of the smooth muscle. The force per smooth muscle cell area was similar in the two groups (ligated: 132 +/- 15; control: 145 +/- 16 mN mm-2, n = 4-5). The maximal shortening velocity was significantly lower in the hypertrophied group (ligated: 0.28 +/- 0.02; control: 0.41 +/- 0.01 optimal length s-1, n = 6). In chemically skinned preparations, activated by maximal thiophosphorylation of the myosin light chains, force was higher in the ligated group compared to the controls but no difference in maximal shortening velocity was observed. In conclusion, the increased transmural pressure is associated with a rapid increase in the amount of smooth muscle in the portal vein. The mechanical data show that after 7 days the force generating ability of the contractile system has increased in proportion to the smooth muscle cell mass. The unaltered maximal shortening velocity in the skinned hypertrophied preparations suggests that the kinetic properties of the maximally activated contractile system are unaltered. The decreased maximal shortening velocity in the intact hypertrophied preparations may reflect alterations in the excitation-contraction coupling.
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