Mitochondrial Ca(2+) uptake is usually thought to occur only when intracellular Ca(2+) concentration ([Ca(2+)](i)) is high. We investigated whether mitochondrial Ca(2+) removal participates in shaping [Ca(2+)](i) signals in arterial smooth muscle over a low [Ca(2+)](i) range. [Ca(2+)](i) was measured using fura 2-loaded, voltage-clamped cells from rat femoral arteries. Both diazoxide and carbon...

The actions of caffeine and ryanodine on the sperrtaneous rhythmic activities in the guinea-pig colon were studied by mechanical tension recordimg. Caffeine redueed the amplitude of the spontaneous rhythniic activity at low cencentration (e.3mM-1 mM). At high concentration (3-IOmM), lt induced a phasic transient contraction, The spontaneous rhythmic activity and a phasic contraction induced by ...

The worldwide overuse of pharmaceuticals and personal care products (PPCPs) has introduced these compounds in exorbitant amounts into aquatic systems. Pharmaceuticals particular have been highlighted among other water contaminants not only due to their significant consumption continuous discharges environments, but also manufacturing processes.

The existence of functionally distinct intracellular Ca(2+) stores has been proposed in some types of smooth muscle. In this study, we sought to examine Ca(2+) stores in the gallbladder by measuring intracellular Ca(2+) concentration ([Ca(2+)](i)) in fura 2-loaded isolated myocytes, membrane potential in intact smooth muscle, and isometric contractions in whole mount preparations. Exposure of i...

The present study characterizes cellular calcium stores that are sensitive to norepinephrine and caffeine in arteries from deoxycorticosterone acetate hypertensive rats. Mesenteric arteries from normotensive and hypertensive rats were excised and cut into helical strips for isometric force recording. In calcium-free solution, phasic contractile responses to norepinephrine (5.9 x 10(-9) to 5.9 x...

this experiment was conducted to evaluate the effects of caffeine and trans-cinnamaldehyde (tc) on growth performance, hematological parameters, stress hormones, immune response, and some blood parameters of broiler chickens. three hundred fifty 1-d-old broiler chicks were randomly assigned to 7 dietary treatments (five pens/ treatment of 10 male broilers each) in a completely randomized design...

Laporte, Régent, and Ismail Laher. Sarcoplasmic reticulum and endothelium independently regulate venous smooth muscle [Ca]i and contraction. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H749–H755, 1999.—In rings of rabbit facial vein (RFV), depletion of sarcoplasmic reticulum (SR) Ca21 by caffeine abolished the subsequent isometric contraction to 25 mM K1 physiological salt solution (25K-PSS)...

When caffeine evokes a contraction, and only then, crayfish muscle fibers become refractory to a second challenge with caffeine for up to 20 min in the standard saline (5 mM K(o)). However, the fibers still respond with contraction to an increase in K(o), though with diminished tension. Addition of Mn slows recovery, but the latter is greatly accelerated during exposure of the fiber to high K(o...

It is well established that DNA lesions trigger cell cycle check-points causing a mitotic delay that is required for their repair before cells enter the mitotic phase. Caffeine, in some cases, can remove this delay and consequently potentiates the yield of induced chromosome aberrations. The objective of this study was to test the effect of a G2 treatment with S-dependent agents (UV light and m...