Search results for "CONTRACTION"
showing 10 items of 1092 documents
Macrophage-induced reactive oxygen species promote myometrial contraction and labor-associated mechanisms
2020
AbstractAt labor, the myometrium is infiltrated by a massive influx of macrophages that secrete high levels of pro-inflammatory cytokines inducing the expression of specific labor-associated markers. However, the interactions between myocytes and macrophages and the role of macrophages in the myometrium at labor remain to be elucidated. In this work, we studied the role of myometrium-infiltrated macrophages and their interaction with myocytes in lipopolysaccharide-induced preterm labor. A co-culture model of human primary myometrial cells and macrophages was developed and validated. Collagen lattices were used to evaluate myocyte contraction. Differentiation steps were assessed by (i) phall…
TRPM8 Channel Activation Reduces the Spontaneous Contractions in Human Distal Colon
2020
The transient receptor potential-melastatin 8 (TRPM8) is a non-selective Ca2+-permeable channel, activated by cold, membrane depolarization, and different cooling compounds. TRPM8 expression has been found in gut mucosal, submucosal, and muscular nerve endings. Although TRPM8 plays a role in pathological conditions, being involved in visceral pain and inflammation, the physiological functions in the digestive system remain unclear as yet. The aims of the present study were: (i) to verify the TRPM8 expression in human distal colon
Levosimendan prevents doxorubicin-induced cardiotoxicity in time- and dose-dependent manner: implications for inotropy.
2019
Abstract Aims Levosimendan (LEVO) a clinically-used inodilator, exerts multifaceted cardioprotective effects. Case-studies indicate protection against doxorubicin (DXR)-induced cardiotoxicity, but this effect remains obscure. We investigated the effect and mechanism of different regimens of levosimendan on sub-chronic and chronic doxorubicin cardiotoxicity. Methods and results Based on preliminary in vivo experiments, rats serving as a sub-chronic model of doxorubicin-cardiotoxicity and were divided into: Control (N/S-0.9%), DXR (18 mg/kg-cumulative), DXR+LEVO (LEVO, 24 μg/kg-cumulative), and DXR+LEVO (acute) (LEVO, 24 μg/kg-bolus) for 14 days. Protein kinase-B (Akt), endothelial nitric oxi…
Angiotensin II type II receptors and colonic dysmotility in 2,4-dinitrofluorobenzenesulfonic acid-induced colitis in rats
2016
Background: Angiotensin II (Ang II), the main peptide of the renin-angiotensin system (RAS), has been suggested to be involved in inflammatory bowel diseases. Since RAS has emerged as gut motility regulator, and dysmotility is associated with intestinal inflammation, our objective was to investigate in rat 2,4-dinitrobenzenesulfonic acid (DNBS)-induced colitis the functionality of RAS and its contribution to colonic motor alterations. Methods: The effects of Ang II on the longitudinal colonic muscular contractility of control and DNBS-treated rats were characterized in vitro. Transcripts encoding for Ang II receptors were investigated by RT-PCR. Key Results: Inflamed preparations showed a l…
Opposite effects of dopamine on the mechanical activity of circular and longitudinal muscle of human colon.
2020
Background Because dopamine (DA) has gained increasing evidence as modulator of gut motility, we aimed to characterize dopaminergic response in human colon, evaluating function and distribution of dopamine receptors in circular vs longitudinal muscle strips. Methods Mechanical responses to DA and dopaminergic agonists on slow phasic contractions and on basal tone were examined in vitro as changes in isometric tension. RT-PCR was used to reveal the distribution of dopaminergic receptors. Key results In spontaneous active circular muscle, DA induced an increase in the amplitude of slow phasic contractions and of the basal tone, via activation of D1-like receptors. DA contractile responses wer…
Spinal plasticity with motor imagery practice.
2019
KEY POINTS: While a consensus has now been reached on the effect of motor imagery (MI) – the mental simulation of an action – on motor cortical areas, less is known about its impact on spinal structures. The current study, using H‐reflex conditioning paradigms, examined the effect of a 20 min MI practice on several spinal mechanisms of the plantar flexor muscles. We observed modulations of spinal presynaptic circuitry while imagining, which was even more pronounced following an acute session of MI practice. We suggested that the small cortical output generated during MI may reach specific spinal circuits and that repeating MI may increase the sensitivity of the spinal cord to its effects. T…
Physiological and Molecular Adaptations to Strength Training
2018
High muscle contraction forces that lead to gains in muscle function, size, and strength characterize resistance exercise training. The purpose of this chapter is to outline the adaptations in myofiber size and metabolism that occur by stimuli of hormones and local growth factors, mechanical and metabolic stress of muscle tissue, and myofibrillar disruptions induced by a resistance exercise bout. The chapter will highlight the network of intracellular pathways (including mTOR signaling) that ultimately lead to increases in gene expression and protein synthesis. Accumulation of acute exercise responses by systematic training over time modulate the muscle proteome that can be observed as chan…
The β3 -adrenoceptor agonist mirabegron increases human atrial force through β1 -adrenoceptors: an indirect mechanism?
2017
Background and Purpose Mirabegron has been classified as a β3-adrenoceptor agonist approved for overactive bladder syndrome. We investigated possible cardiac effects of mirabegron in the absence or presence of β-adrenoceptor subtype antagonists. In view of its phenylethanolamine structure, we investigated whether mirabegron has indirect sympathomimetic activity by using neuronal uptake blockers. Experimental Approach Right atrial trabeculae, from non-failing hearts, were paced and contractile force measured at 37°C. Single concentrations of mirabegron were added in the absence or presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX), β3 (L-748,337), β1 (CGP 20712A),…
Smooth muscle and neural dysfunction contribute to different phases of murine postoperative ileus.
2015
Background Postoperative ileus (POI) is characterized by a transient inhibition of gastrointestinal (GI) motility after abdominal surgery mediated by the inflammation of the muscularis externa (ME). The aim of this study was to identify alterations in the enteric nervous system that may contribute to the pathogenesis of POI. Methods Gastrointestinal transit, contractility of isolated smooth muscle strips and inflammatory parameters were evaluated at different time points (1.5 h to 10 days) after intestinal manipulation (IM) in mice. Immune-labeling was used to visualize changes in myenteric neurons. Key Results Intestinal manipulation resulted in an immediate inhibition of GI transit recove…
Neurotrophic and neuroprotective effects of muscle contraction
2016
Background: Physical activity has been shown to be associated with reduced risk of coronary heart disease but the same effect seems to be produced in neurological diseases. Objective: In this review, we focused on the interplay between physical activity and some neurological conditions (Stroke, dementia, epilepsy, headache, Parkinson’ s disease, amyotrophic lateral sclerosis, multiple sclerosis, insomnia, depression and anxiety) with the aim of describing the potential role of physical activity in the prevention of such diseases and the physiological mechanisms involved in these processes. Results: Despite a growing body of evidence which reveals that physical activity is able to reduce the…