Neuro-effector transmission and mechanical responses in smooth muscles of the dog iris were studied, using tension recording and microelectrode methods. Electrical stimulations evoked an initial phasic contraction followed by relaxation in both the iris sphincter and dilator muscles. Atropine selectively suppressed phasic contraction of the sphincter and relaxation of the dilator muscle, while ...

Nitric oxide (NO) has been shown to be involved in skeletal muscle glucose uptake during contraction/exercise, especially in individuals with Type 2 diabetes (T2D). To examine the potential mechanisms, we examined the effect of local NO synthase (NOS) inhibition on muscle glucose uptake and muscle capillary blood flow during contraction in healthy and T2D rats. T2D was induced in Sprague-Dawley...

Dystonia is generally referred to belong to the generic terms, muscle spasm and muscle stiffness. Muscle spasms would be any involuntary abnormal muscle contraction, regardless of whether it is painful or not, that cannot be usually terminated by voluntary relaxation. Muscle stiffness is an involuntary muscle shortening that usually lasts for seconds to minutes, but may be sustained. Sustained ...

Hydrophobic bile acids impair gallbladder emptying in vivo and inhibit gallbladder muscle contraction in response to CCK-8 in vitro. This study was aimed at determining the mechanisms of muscle cell dysfunction caused by bile acids in guinea pig gallbladders. Muscle cells were obtained by enzymatic digestion. Taurochenodeoxycholic acid (TCDC), a hydrophobic bile acid, caused a contraction of up...

Hu W, Mahavadi S, Li F, Murthy KS. Upregulation of RGS4 and downregulation of CPI-17 mediate inhibition of colonic muscle contraction by interleukin-1 . Am J Physiol Cell Physiol 293: C1991–C2000, 2007. First published October 24, 2007; doi:10.1152/ajpcell.00300.2007.—The pro-inflammatory cytokine IL-1 contributes to the reduced contractile responses of gut smooth muscle observed in both animal...

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...

Context. Maximal voluntary isometric contraction, a method quantitatively assessing muscle strength, has proven to be reliable, accurate and sensitive in amyotrophic lateral sclerosis. Hand-held dynamometry is less expensive and more quickly applicable than maximal voluntary isometric contraction. Objective. To investigate if hand-held dynamometry is as reliable and valid as maximal voluntary i...

Exaggerated contraction of airway smooth muscle is the major cause of symptoms in asthma, but the mechanisms that prevent exaggerated contraction are incompletely understood. Here, we showed that integrin α9β1 on airway smooth muscle localizes the polyamine catabolizing enzyme spermidine/spermine N1-acetyltransferase (SSAT) in close proximity to the lipid kinase PIP5K1γ. As PIP5K1γ is the major...

Using transcranial magnetic stimulation (TMS), differences in the excitability changes of motor evoked potentials (MEPs) between isometric (force task) and isotonic (movement task) muscle contractions in a distal (first dorsal interosseous; FDI) and a proximal (middle deltoid; MD) muscle were studied. In the FDI muscle, the active threshold of MEP recruitment was significantly lower in the isot...

A previous study has shown increased Fos-like immunoreactivity (FLI), a marker of neural activation, in the nucleus of the solitary tract (NTS) and the ventrolateral medulla (VLM) after static muscle contraction elicited by electrical stimulation of L7 and S1 ventral roots of the spinal cord in anesthetized, baroreceptor-intact cats. Because the electrically induced static muscle contraction re...