background: cassia italica or senna is a wild plant distributed in south of iran. it increased water consumption and has a laxative effect. in traditional medicine this plant has been used for the dysmenorrheal. objective: in this study we investigated the effect of aqueous extract of cassia italica on uterus contraction. materials and methods: virgin wistar rats 200-300g were purchased. after ...

During contractions, regulation of microvascular oxygen partial pressure (Pmv(O2)), which drives blood-myocyte O2 flux, is a function of skeletal muscle fiber type and oxidative capacity and can be altered by exercise training. The kinetics of Pmv(O2) during contractions in predominantly fast-twitch muscles evinces a more rapid fall to far lower levels compared with slow-twitch counterparts. Pe...

OBJECTIVE Studies have suggested that sex differences in endothelial function in part account for the lower incidence of cardiovascular disease in premenopausal women compared with men. Less is known about the role of smooth muscle. We hypothesized that signaling mechanisms that regulate calcium sensitivity in vascular muscle also play a role in determining sex differences in contractile functi...

We hypothesized that AMP-activated protein kinase-related kinase 5 (ARK5)/novel kinase family 1 (NUAK1), an AMP-activated protein kinase (AMPK)-related kinase that has been found to be stimulated by protein kinase B (Akt), would be expressed in rat skeletal muscle and activated by electrically elicited contractions, 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR), or insulin. We ...

Rapid-onset vasodilation (ROV) following single muscle contractions has been examined in the forearm of humans, but has not yet been characterized in the leg. Given known vascular differences between the arm and leg, we sought to characterize ROV following single muscle contractions in the leg. Sixteen healthy men performed random ordered single contractions at 5, 10, 20, 40, and 60% of their m...

The aim of this study was to investigate the modulation of in vitro rat colonic circular muscle contractions by dextran sodium sulfate (DSS)-induced inflammation and in spontaneous inflammation in HLA-B27 rats. We also examined the potential role of hydrogen peroxide (H(2)O(2)) in modulating excitation-contraction coupling. The muscle strips from the middle colon generated spontaneous phasic co...

Background. Muscles not only shorten during contraction to perform mechanical work, but they also bulge radially because of the isovolumetric constraint on muscle fibres. Muscle bulging may have important implications for muscle performance, however quantifying three-dimensional (3D) muscle shape changes in human muscle is problematic because of difficulties with sustaining contractions for the...

The main objective of the study was to investigate and simulate skeletal muscle force production during and after isometric contractions, active muscle lengthening and active muscle shortening. The motivation behind this work was to improve the dominant model of muscle force generation based on the theories of Hill from 1938. Effects of residual force enhancement and force depression were obser...

Muscle contractions are driven by neurotransmitters released at neuromuscular junctions. In this issue, Beg et al. (2008) report that protons, in the absence of neurotransmitters and neurons, can stimulate muscle contractions involved in the defecation cycle of the worm Caenorhabditis elegans. Their results identify protons as a new intercellular messenger and suggest that proton-mediated inter...

Human colonic circular muscle produces spontaneous phasic contractions that are reduced in ulcerative colitis. How the spontaneous phasic contractions develop and why they decrease in ulcerative colitis are not known. We found that spontaneous phasic contractions of normal sigmoid circular muscle strips were significantly reduced by 90-min incubation with tetrodotoxin (10(-5) M), which blocked ...