Effects of Diltiazem on Guinea Pig Portal Vein in Hypertonic Solution

Adrenoceptor study of guinea-pig superior mesenteric--portal vein.

INTRODUCTION Vasoactive agents have been extensively studied in precapillary resistance vessels but little emphasis has been directed to their effect on the venous system even though veins are probably important in governing haemodynamics. Approximately half the blood volume lies within the venous system, therefore a doubling in venous tone could increase the circulating volume by 25% and conve...

Possible Relaxant Effects of Thymoquinone on Guinea Pig Tracheal Chain

In the previous studies the relaxant, anti-cholinergic (functional antagonism) and anti-histaminic effects of Nigella sativa have been demonstrated on guinea pig tracheal chains. To elucidate the main substance responsible for the relaxant effect of this plant, the effect of thymoquinone, one of the main constituent of Nigella sativa was examined in this study. The bronchodilatory effects of th...

Effects of diltiazem on the electrical and mechanical activity of the guinea-pig ureter smooth muscle.

PH-induced changes in calcium: functional consequences and mechanisms of action in guinea pig portal vein.

The effects of changing extracellular (pH(o)) and intracellular pH (pH(i)) on force and the mechanisms involved in the guinea pig portal vein were investigated to better understand the control of tone in this vessel. When pH(o) was altered, the effects on force and calcium were the same irrespective of whether force had been produced spontaneously by high-K depolarization or by norepinephrine; ...

Early exposure to hypertonic solution strongly intensifies the effects of K+ channel opener, rilmakalim, in guinea pig ventricular myocytes.

We report here that early exposure of guinea pig ventricular myocytes to hypertonic solution (approximately 400 mOsm compared to 280 mOsm in isotonic solution) increased the potency of rilmakalim to evoke ATP-sensitive K+ current 10 times (pD2 = 7.44 +/- 0.11 compared to pD2 = 6.49 +/- 0.18 in isotonic solution) without changing Emax, and observed effect was completely reversed by glibenclamide...