VASODILATORS AND CALCIUM-45 UPTAKE IN VASCULAR SMOOTH AND CARDIAC MUSCLE

1981 ◽  
Vol 9 (2) ◽  
pp. 139P-139P
Author(s):  
STIG-LENNART BOSTROM ◽  
BENGT LJUNG
Keyword(s):  
Cell Membrane ◽  
Portal Vein ◽  
Cardiac Muscle ◽  
Cellular Uptake ◽  
Papillary Muscle ◽  
Calcium Antagonists ◽  
Contractile Activity ◽  
Rat Portal Vein ◽  
Ic50 Values

A variety of substances, chemically heterogenous, has been classified as calcium antagonists. They inhibit the contractile activity of vascular smooth and cardiac muscle. This has been attributed to a blockade of the so called slow channels of the cell membrane causing an inhibition of the transmembrane influx of calcium. In the experiments reported we have studied the effect of verapamil, nifedipine and felodipine (pINN) on the uptake of calcium-45 in the rat portal vein and papillary muscle. The results show that the substances, at their IC50 values, did not decrease the cellular uptake of calcium-45, measured with the lanthanum method.

Differential actions of exogenous and intracellular spermine on contractile activity in smooth muscle of rat portal vein

1995 ◽  
Vol 154 (3) ◽  
pp. 355-365 ◽  
Author(s):  
B.-O. NILSSON ◽  
M. GOMEZ ◽  
R. SANTIAGO CARRILHO ◽  
I. NORDSTRÖM ◽  
P. HELLSTRAND
Keyword(s):  
Smooth Muscle ◽  
Portal Vein ◽  
Contractile Activity ◽  
Rat Portal Vein

Modifications evoked by piretanide in the mechanical activity of cardiovascular tissues

1985 ◽  
Vol 63 (4) ◽  
pp. 283-286
Author(s):  
J. L. Lacuara ◽  
R. D. Ruiz ◽  
M. Fiol de Cuneo
Keyword(s):  
Portal Vein ◽  
Contractile Activity ◽  
Mechanisms Of Action ◽  
Mechanical Activity ◽  
Vascular Tissues ◽  
Cardiovascular Tissues ◽  
Rat Portal Vein ◽  
Isolated Rat

The effects of piretanide upon mechanical activity and pharmacological reactivity of vascular and myocardial tissues from normotensive rats were investigated. Magnitude of phasic contractions of isolated rat portal vein was diminished by the drug in a dose-related manner; contractile depression induced by piretanide (10−4 M) was less in the presence of insulin (0.1 U/mL), glucose (22 mM) or pyruvate (5 mM). Responses to KCl (90 mM), or norepinephrine (2.5 × 10−5 M) were also reduced. Contractile activity of atria and ventricle strips was diminished only when piretanide reached 10−4 M. Results support direct actions of piretanide upon cardiac and vascular tissues. Possible mechanisms of action are discussed.

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