Measurements of basal d-glucose transport through GLUT1 across the intact plasma membrane of isolated segments from single fast- and slow-twitch skeletal muscle fibres of rat.

Aim: To develop a method for direct measurement of the fluorescent d-glucose analogue 2-NBDG transport across the plasma membrane of single skeletal muscle fibres and derive the theoretical framework for determining the kinetic parameters for d-glucose transport under basal conditions.

Methods: A novel method is described for measuring free 2-NBDG transport across plasma membrane of single rat muscle fibres at rest. The 2-NBDG uptake was >90% suppressed by 100 µM cytochalasin B in both fast-twitch and slow-twitch fibres, indicating that the 2-NBDG transport is GLUT-mediated.

Effects of intrauterine growth restriction on Ca-activated force and contractile protein expression in the mesenteric artery of 1-year-old Wistar-Kyoto rats.

Intrauterine growth restriction (IUGR) affects vascular reactivity in older rats, but at present the causative factors for this change are unknown. Therefore, we investigated downstream events associated with vascular reactivity, specifically, Ca-regulated force production and shifts in contractile protein content. The mesenteric artery from male and female 1-year-old Wistar-Kyoto rats was examined using two distinct experimental growth restriction models.

The effect of intrauterine growth restriction on Ca -activated force and contractile protein expression in the mesenteric artery of adult (6-month-old) male and female Wistar-Kyoto rats.

Intrauterine growth restriction (IUGR) is known to alter vascular smooth muscle reactivity, but it is currently unknown whether these changes are driven by downstream events that lead to force development, specifically, Ca -regulated activation of the contractile apparatus or a shift in contractile protein content. This study investigated the effects of IUGR on Ca -activated force production, contractile protein expression, and a potential phenotypic switch in the resistance mesenteric artery of both male and female Wistar-Kyoto (WKY) rats following two different growth restriction models. Pregnant female WKY rats were randomly assigned to either a control (C; N = 9) or food restriction diet (FR; 40% of control; N = 11) at gestational day-15 or underwent a bilateral uterine vessel ligation surgery restriction (SR; N = 10) or a sham surgery control model (SC; N = 12) on day-18 of gestation.

The effects of Suramin on Ca activated force and sarcoplasmic reticulum Ca release in skinned fast-twitch skeletal muscle fibers of the rat.

Suramin has long been used in the treatment of various human diseases. Intravenous infusions of Suramin are commonly administered to patients over extended periods of time but there are a number of significant contraindications with peripheral muscle weakness being one of the most frequently reported. Previous work has shown that even after a single infusion (300 mg kg) Suramin remains in skeletal muscle in effective concentrations (11.

-nitrosylation and -glutathionylation of Cys134 on troponin I have opposing competitive actions on Ca sensitivity in rat fast-twitch muscle fibers.

Nitric oxide is generated in skeletal muscle with activity and decreases Ca sensitivity of the contractile apparatus, putatively by nitrosylation of an unidentified protein. We investigated the mechanistic basis of this effect and its relationship to the oxidation-induced increase in Ca sensitivity in mammalian fast-twitch (FT) fibers mediated by glutathionylation of Cys134 on fast troponin I (TnI). Force-[Ca] characteristics of the contractile apparatus in mechanically skinned fibers were assessed by direct activation with heavily Ca-buffered solutions.