scholarly journals EFFECTS OF CALCIUM ANTAGONISTS ON CONTRACTILE RESPONSE OF GUINEA-PIG TAENIA CAECUM TO CARBACHOL IN A CALCIUM DEFICIENT, POTASSIUM RICH SOLUTION

1975 ◽  
Vol 25 (2) ◽  
pp. 214-216 ◽  
Author(s):  
Hidenori OHASHI ◽  
Tadashi TAKEWAKI ◽  
Nobuo SHIBATA ◽  
Toshiaki OKADA
Keyword(s):  
Guinea Pig ◽  
Calcium Antagonists ◽  
Contractile Response ◽  
Rich Solution

scholarly journals Calcium Source for Contractile Response of Guinea Pig Taenia Caecum to Carbachol in a Calcium Deficient, Potassium Rich Solution

1978 ◽  
Vol 28 (4) ◽  
pp. 561-568 ◽  
Author(s):  
Nobuo Shibata ◽  
Hidenori Ohashi ◽  
Tadashi Takewaki ◽  
Toshiaki Okada
Keyword(s):  
Guinea Pig ◽  
Contractile Response ◽  
Calcium Source ◽  
Rich Solution

Calcium channels and excitation–contraction coupling in cardiac cells. I. Two components of contraction in guinea-pig papillary muscle

1987 ◽  
Vol 65 (9) ◽  
pp. 1821-1831 ◽  
Author(s):  
E. Honoré ◽  
M. M. Adamantidis ◽  
B. A. Dupuis ◽  
C. E. Challice ◽  
P. Guilbault
Keyword(s):  
Membrane Potential ◽  
Guinea Pig ◽  
Papillary Muscle ◽  
Cardiac Cells ◽  
Resting Membrane Potential ◽  
Tonic Component ◽  
Contraction Coupling ◽  
Rich Solution ◽  
The Relationship ◽  
Guinea Pig Atria

Biphasic contractions have been obtained in guinea-pig papillary muscle by inducing partial depolarization in K+-rich solution (17 mM) containing 0.3 μM isoproterenol; whereas in guinea-pig atria, the same conditions led to monophasic contractions corresponding to the first component of contraction in papillary muscle. The relationships between the amplitude of the two components of the biphasic contraction and the resting membrane potential were sigmoidal curves. The first component of contraction was inactivated for membrane potentials less positive than those for the second component. In Na+-low solution (25 mM), biphasic contraction became monophasic subsequent to the loss of the second component, but tetraethylammonium unmasked the second component of contraction. The relationship between the amplitude of the first component of contraction and the logarithm of extracellular Ca2+ concentration was complex, whereas for the second component it was linear. When Ca2+ ions were replaced by Sr2+ ions, only the second component of contraction was observed. It is suggested that the first component of contraction may be triggered by a Ca2+ release from sarcoplasmic reticulum, induced by the fast inward Ca2+ current and (or) by the depolarization. The second component of contraction may be due to a direct activation of contractile proteins by Ca2+ entering the cell along with the slow inward Ca2+ current and diffusing through the sarcoplasm. These results do not exclude the existence of a third "tonic" component, which could possibly be mixed with the second component of contraction.

Effects of several calcium antagonists and dipyridamole in the isolated perfused guinea pig heart

Life Sciences ◽  
1980 ◽  
Vol 27 (24) ◽  
pp. 2339-2346 ◽  
Author(s):  
Stanley R. Jolly ◽  
Lawrence A. Menahan ◽  
Garrett J. Gross
Keyword(s):  
Guinea Pig ◽  
Calcium Antagonists ◽  
Guinea Pig Heart

Effects of ethanol on contractile response of gall bladder isolated from guinea pig

1993 ◽  
Vol 248 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Hidehisa Masui ◽  
Ichiro Wakabayashi ◽  
Katsuhiko Hatake ◽  
Sachiko Yoshimoto ◽  
Kunihiro Sakamoto
Keyword(s):  
Gall Bladder ◽  
Guinea Pig ◽  
Contractile Response

Calcium channels and excitation–contraction coupling in cardiac cells. II. A pharmacological study of the biphasic contraction in guinea-pig papillary muscle

1987 ◽  
Vol 65 (9) ◽  
pp. 1832-1839 ◽  
Author(s):  
E. Honoré ◽  
M. M. Adamantidis ◽  
B. A. Dupuis ◽  
C. E. Challice ◽  
P. Guilbault
Keyword(s):  
Guinea Pig ◽  
Papillary Muscle ◽  
Positive Inotropic Effect ◽  
Pharmacological Study ◽  
Negative Inotropic Effect ◽  
Cardiac Cells ◽  
Inotropic Effect ◽  
Free Solution ◽  
Contraction Coupling ◽  
Rich Solution

Biphasic contractions were obtained in guinea-pig papillary muscle by inducing partial depolarization in K+-rich solution (17 mM) in the presence of 0.3 μM isoproterenol. Mn2+ ions inhibited the two components of contraction in a similar way. Nifedipine and particularly Cd2+ ions specifically inhibited the second component of contraction. Isoproterenol and BAY K 8644 markedly increased the amplitude of the second component (P2) of contraction. Nevertheless, a moderate positive inotropic effect of isoproterenol was found on the first component (P1) of contraction when excitability was restored by 0.2 mM Ba instead of isoproterenol. Acetylcholine and hypoxia decreased the amplitude of the second component of contraction to a greater extent. In the presence of digoxin or Na+-free solution, P1was strongly increased. When sarcoplasmic reticular function was hindered by 1 mM caffeine or in the presence of Ca2+-free Sr2+ solution, digoxin always induced a negative inotropic effect on P2. Inversely in these conditions the transient positive inotropic effect of Na+-free solution was strongly reduced. These results are consistent with the hypothesis that the late component of contraction is triggered by the slow inward Ca2+ current and that the early component is due to Ca2+ release from the sarcoplasmic reticulum.

The release of slow-reacting substance of anaphylaxis from guinea pig lung: effects of calcium antagonists

1985 ◽  
Vol 63 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Melissa A. Damiano ◽  
Edward J. Barbieri
Keyword(s):  
Guinea Pig ◽  
Intracellular Calcium ◽  
Lung Tissue ◽  
Calcium Antagonists ◽  
Lung Parenchyma ◽  
Free Medium ◽  
Bicarbonate Buffer ◽  
Normal Medium ◽  
Voltage Dependent ◽  
High Concentrations

The effects of three calcium antagonists, verapamil, lanthanum, and 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) were studied on the release of slow-reacting substance of anaphylaxis (SRS-A) from ovalbumin-sensitized chopped guinea pig lung parenchyma in calcium-containing and calcium-free media. The SRS-A levels (mean ± SEM) obtained from tissues incubated in normal and calcium-free Krebs–bicarbonate buffer were 51 ± 8 (N = 19) and 21 ± 4 (N = 14) U/mL, respectively. TMB-8 (0.1–10 μM) a reported intracellular calcium antagonist, reduced antigen-stimulated SRS-A release from lung tissue incubated in calcium-containing, but not calcium-free, medium; A23187-induced SRS-A release from normal guinea pig lung was not significantly altered by TMB-8 at concentrations up to 10 μM. Verapamil and lanthanum consistently reduced SRS-A release only at high concentrations (100 μM and 1 mM, respectively). The quantities of SRS-A released from lung tissue incubated in the presence of verapamil in normal medium were similar to those obtained in calcium-free medium. Tissues incubated in the presence of potassium chloride (60 and 100 mM) did not release significant quantities of SRS-A, and release which did occur was not blocked by verapamil, suggesting that antigen-induced SRS-A release is not dependent on membrane depolarization and that verapamil was not exerting inhibition via blockade of voltage-dependent calcium channels. These data suggest that although intracellular calcium is important for the regulation of SRS-A secretion from guinea pig lung tissue, extracellular calcium is necessary for optimal release of SRS-A.

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