PURPOSE Mesangial cells play an important role in regulating glomerular filtration by altering their cellular tone. We report the presence of a sodium glucose cotransporter (SGLT) in rat mesangial cells. This study in rat mesangial cells aimed to evaluate the expression and role of SGLT2. METHODS The SGLT2 expression in rat mesangial cells was assessed by Western blotting and reverse transcri...

Raising extracellular K+ concentration ([K+](o)) around mesenteric resistance arteries reverses depolarization and contraction to phenylephrine. As smooth muscle depolarizes and intracellular Ca(2+) and tension increase, this effect of K+ is suppressed, whereas efflux of cellular K+ through Ca(2+)-activated K+ (K(Ca)) channels is increased. We investigated whether K+ efflux through K(Ca) suppre...

Single bovine ventricular myocytes were superfused with Tyrode solution containing 1.8 mM CaCl2. The cells did not bear external load and contracted isotonically. Contraction and relaxation were characterized by the shortening and relengthening of the sarcomeres which resembled in their time course the isometric twitches of bovine papillary muscles. Resemblance was also found in regard to posit...

The entire concept of ion channels as molecular machines to gate ion traffic across the membrane has only recently been generally recognized, even though ion channels are found in almost all cells. Na+ and Ca2+ channels are the basis of excitability, and in the heart they generate the rhythm, coordinating and controlling cardiac contraction. Dysfunction of ion channels results in arrhythmias th...

Ramp isometric contractions determine peak torque (PT) and neuromuscular activation (NA), and ballistic contractions can be used to evaluate rate of torque development (RTD) and electrical mechanical delay (EMD). The purposes of this study were to assess the number of sessions required to stabilize ramp and ballistic PT and to compare PT and NA between contractions in older adults. Thirty-five ...

1 The effect of ethacrynic acid (EA) was studied on guinea-pig and rat vas deferens in vitro.2 EA contracted the guinea-pig but not the rat vas deferens in a dose-dependent manner (50-800 mug/ml). Tyramine caused contraction in 10 out of 18 guinea-pig vas deferens; EA caused contraction in 17 of the preparations which did not respond to tyramine. Repeated doses of EA produced tachyphylaxis, but...

The objective of this study was to determine whether the different time-course characteristics of α1-adrenoceptor-mediated contraction in arteries can be related to the subtypes involved. Contractile responses to noradrenaline (NA) were compared with inositol phosphate accumulation and extracellular signal-regulated kinase (ERK)1/2 phosphorylation after α1-agonist stimuli in the same vessels in...

The effects of alterations in the frequency of contraction over the range from 94 to 220/min on left ventricular pressure, diameter, and dP/dt were studied in 10 dogs instrumented with ultrasonic diameter ganges and miniature pressure gauges. The same dogs were studied on separate days in the conscious state, after general anesthesia with pentobarbital Na, 30 mg/kg, and in the conscious state a...

Pulmonary arteries (PA) are resistant to the vasodilator effects of extracellular acidosis in systemic vessels; the mechanism underlying this difference between systemic and pulmonary circulations has not been elucidated. We hypothesized that RhoA/Rho-kinase-mediated Ca2+ sensitization pathway played a greater role in tension development in pulmonary than in systemic vascular smooth muscle and ...

The majority of Na channels in the heart are composed of the tetrodotoxin (TTX)-resistant (KD, 2 to 6 micromol/L) "cardiac" NaV1.5 isoform; however, TTX-sensitive (KD, 1 to 25 nmol/L) "neuronal" Na channel isoforms have recently been detected in several cardiac preparations. In the present study, we determined the functional subcellular localization of Na channel isoforms (according to their TT...