scholarly journals Local Heterogeneous Electrical Restitution Properties of Rabbit Atria

2016 ◽  
Vol 27 (6) ◽  
pp. 743-753 ◽  
Author(s):  
AMR AL ABED ◽  
NIGEL H. LOVELL ◽  
SOCRATES DOKOS
Keyword(s):  
Rabbit Atria

The effect of pH on rabbit atrial response to histamine

1976 ◽  
Vol 54 (2) ◽  
pp. 118-127 ◽  
Author(s):  
M. J. Hughes ◽  
I. A. Coret
Keyword(s):  
Histamine Receptor ◽  
Maximum Response ◽  
Force Of Contraction ◽  
Histamine Concentration ◽  
Adenyl Cyclase Activity ◽  
Chronotropic Response ◽  
Spontaneous Rate ◽  
Histamine Response ◽  
Ph Range ◽  
Rabbit Atria

The chronotropic response of isolated rabbit atria in normal Tyrode's medium increases monotonically with increasing doses of histamine (9 × 10−7–9 × 10−4 M). Plots of the inverse of response against the inverse of concentration were linear; and from these plots were derived values for the theoretical maximum response at 'infinite' dose and for the histamine concentration required to evoke a half maximum response. Alteration of pH by changing [HCO3−] at constant pCO2, [Na+] and osmolality did not appreciably affect the response to histamine in the range pH 7.0–7.6. However, at pH below 7.0 the magnitude of histamine response was reduced at all concentrations of histamine tested. In the pH range 7.0–7.6, additions of NaHCO3 at constant pCO2 increased the spontaneous rate of rabbit atria (in the absence of histamine); however, there was little effect of changing pH (in this range) by altering [HCO3−] at constant pCO2 when [Na+] and osmolality were kept constant. Immersion in solutions at pH's less than 7.0 led to decline in spontaneous rate and force of contraction. It is probable that depression of adenyl cyclase activity rather than a specific change in ionization of histamine receptor is responsible for a decreased response to histamine at pH 6.9.

scholarly journals Ursolic acid accentuates contractile and secretory functions in beating rabbit atria

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Hao Zhen Cui ◽  
Hye Ran Choi ◽  
Kyung Woo Cho ◽  
Dae Gill Kang ◽  
Ho Sub Lee
Keyword(s):  
Ursolic Acid ◽  
Rabbit Atria

Atrial pressure, distension, and pacing frequency in ANP secretion in isolated perfused rabbit atria

1991 ◽  
Vol 260 (1) ◽  
pp. R39-R46 ◽  
Author(s):  
K. W. Cho ◽  
K. H. Seul ◽  
S. H. Kim ◽  
K. M. Seul ◽  
G. Y. Koh
Keyword(s):  
Electrical Stimulation ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Atrial Pressure ◽  
Atrial Pacing ◽  
Atrial Myocytes ◽  
Volume Changes ◽  
Series Of Experiments ◽  
The Relationship ◽  
Rabbit Atria

It has been suggested in this laboratory that the principal stimulus for the secretion of atrial natriuretic peptide (ANP) is the reduction of atrial distension and that the secretion of ANP is dependent on both atrial reduction volume and reduction frequency. To investigate the relationship among the changes in atrial pressure, distension, pacing frequency, and ANP secretion, we performed a series of experiments in the isolated perfused rabbit atria. Increase in atrial pressure without changes in transmural pressure and thus without volume changes did not raise immunoreactive ANP (irANP) secretion. Atrial distension without changes in intracavitary atrial pressure increased irANP secretion with the reduction. Electrical stimulation with atrial distension resulted in an increase in irANP secretion in proportion to pacing frequency. Incremental response of irANP secretion to electrical stimulation was accentuated by increasing atrial distension. Neither atrial pacing without distension nor distension without pacing raised irANP secretion. These results suggest that the direct and principal stimulus for irANP secretion in response to atrial pacing and distension is the length shortening of atrial myocytes and that the incremental response of irANP secretion to increasing pacing frequency is the result of an increase in frequency of the length shortening of atrial myocytes.

Transmembrane potentials and fluxes in isolated rabbit atria

1959 ◽  
Vol 196 (6) ◽  
pp. 1292-1296 ◽  
Author(s):  
R. L. Klein ◽  
W. C. Holland
Keyword(s):  
Action Potential ◽  
Active Transport ◽  
Terminal Phase ◽  
Transmembrane Potentials ◽  
Unidirectional Fluxes ◽  
Rabbit Atria

Data are presented from a study of transmembrane potentials and unidirectional fluxes of K42 under identical conditions in isolated rabbit atria. The effects of acetylcholine and varying extracellular concentrations of Na, K and Ca were investigated. Particular emphasis has been placed on the role of Ca and on the terminal phase of repolarization of the action potential, namely the negative after potential. Data are given which support the contention that the duration of the negative after potential depends on an active transport of K or Na, or both.

scholarly journals Intracellular Na and K concentrations of rabbit atria, in relation to the action of quinidine

1962 ◽  
Vol 160 (3) ◽  
pp. 483-493 ◽  
Author(s):  
P. J. Goodford ◽  
E. M. Vaughan Williams
Keyword(s):  
Rabbit Atria
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