444 Dissociation of the augmentation of cardiac contractile force from the activation of myocardial phosphorylase by catecholamines

Mayer, S.; Cotten, M. De V.; Moran, Neil C.

doi:10.1016/0006-2952(61)90633-5

Cited by 21 publications

(24 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The phosphorylase a activity, consistent with numerous other reports (15,16), was low, on the order of 2 to 4% of the total activity. Hence, an increase in neither total phosphorylase nor phosphorylase a activity can account for the decrease in cardiac glycogen found in adrenalectomized rats.…”

Section: Discussionsupporting

confidence: 91%

Influences of Corticosteroids on Cardiac Glycogen Concentration in the Rat

Daw

Lefer

Berne

1968

Circulation Research

View full text Add to dashboard Cite

Bilateral adrenalectomy resulted in a decrease (4.97 to 2.79 mg/g) in cardiac glycogen concentration in pentobarbital-anesthetized rats. Similar differences were observed at 10 to 14 days and at 27 days after adrenalectomy. Sham-adrenalectomized rats had normal cardiac glycogen concentration (4.98 mg/g). Total phosphorylase and phosphorylase a activities and glucose-6-phosphate concentrations in hearts obtained from adrenalectomized rats were not significantly different from controls. Total glycogen transferase activity was decreased in adrenalectomized rats and for any given glycogen concentration, the percent of the glycogen transferase in the independent form (percent transf erase I) was significantly lower in the adrenalectomized rats than in the intact controls. The glucocorticoid dexamethasone (40 /ig/day) prevented the decreases in cardiac glycogen concentration and percent transferase I in adrenalectomized rats. In the intact rat dexamethasone (40 /ig/day) increased cardiac glycogen concentration and total transferase activity to above control levels as did larger doses in both adrenalectomized and control rats. The mineralocorticoid deoxycorticosterone acetate (DOCA), had relatively little effect on cardiac glycogen concentration. Conclusion: glucocorticoids exert a regulatory role in cardiac glycogen metabolism. ADDITIONAL KEY WORDSglycogen transferase glycogen synthetase glycogen phosphorylase adrenalectomy glucocorticoids mineralocorticoids deoxycorticosterone acetate (DOCA) dexamethasone myocardial glycogen heart glycogen glucose-6-phosphate• In 1956, Russell and Bloom (1) reported that adrenalectomy does not alter the cardiac glycogen concentration in rats. However, Barta and Pavlovicova (2) recently demonstrated that cardiac glycogen is decreased in adrenalectomized rats. Furthermore, Suzuki (3) has shown that adrenalectomy markedly reduced the size and number of glycogen granules in myocardial cells in rats. In view of these recent developments, we undertook the present investigation with the following objectives: (1) to resolve this controversy, (2) to ascertain whether changes in the ac- This investigation was supported in part by U. S. Public Health Service Grants HE 06031 and HE 09924 from the National Heart Institute.Accepted for publication March 4, 1968.tivities of two major enzymes of glycogen metabolism, glycogen transferase (synthetase) and glycogen phosphorylase, are involved in the metabolic mechanism responsible for any changes in cardiac glycogen concentration consequent to adrenalectomy or corticosteroid treatment, and (3) to determine whether the corticosteroids exert a regulatory function in cardiac glycogen metabolism.Methods Animals,-Male, albino, Sprague-Dawley rats (210 to 350 g) were used. Rats were anesthetized with ether and bilaterally adrenalectomized via a dorsal lumbar approach. Rats with sham operations were similarly prepared except that the adrenals were not removed. The drinking water of all adrenalectomized-rats was 0.9% NaCl. All rats were fed Purina rat ...

show abstract

Section: Discussionsupporting

confidence: 91%

Influences of Corticosteroids on Cardiac Glycogen Concentration in the Rat

Daw

Lefer

Berne

1968

Circulation Research

View full text Add to dashboard Cite

show abstract

“…However, it is known that the ,f-receptors alone are involved in the metabolic actions of catecholamines on cardiac (Mayer & Moran, 1960;Kennedy & Ellis, 1963) and skeletal (Ali, Antonio & Haugaard, 1964;Hornbrook & Brody, 1963) muscle. Further, it has recently been found that the action of adrenaline in activating phosphorylase in the rat uterus and in the taenia of the guinea-pig is also mediated by fl-receptors Diamond & Brody, 1965.…”

Section: Discussionmentioning

confidence: 99%

The effect of noradrenaline on the permeability of depolarized intestinal smooth muscle to inorganic ions

Jenkinson¹,

Morton²

1967

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Radio-isotopes have been used to study the effect of noradrenaline on the permeability of the taenia of the guinea-pig caecum to inorganic ions. The preparations were bathed at either 10 or 200 C in solutions containing a high concentration of potassium, in order to depolarize the fibres and so avoid ionic movements secondary to changes in membrane potential.2. Under these conditions noradrenaline increased both inward and outward fluxes of potassium whilst having little effect on the exchange of chloride.3. No effect of noradrenaline on the uptake of sodium could be detected, whereas carbachol (carbamyl choline chloride), applied under identical conditions, caused a significant increase at a concentration chosen to match the effect of noradrenaline on potassium exchange.4. These results are discussed in relation to the hypothesis that an increase in potassium permeability contributes to the inhibitory actions of noradrenaline on intestinal smooth muscle.

show abstract

“…Recently it has been demonstrated that, in the myocardium, the increased force of contraction precedes the activation of phosphorylase and of phosphofructokinase (Mayer, Cotten & Moran, 1963;Drummond, Valadares & Duncan, 1964;Williamson, 1966). Moreover, adrenaline can exert a positive inotropic effect on skeletal muscle under aerobic conditions when glycolysis is inhibited by iodoacetate (Ellis & Beckett, 1954).…”

Section: Introductionmentioning

confidence: 99%

The effect of adrenaline on the adenosine otriphosphate and creatine phosphate content of intestinal smooth muscle

Bueding¹,

Bülbring²,

Gercken³

et al. 1967

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. The smooth muscle of guinea-pig taenia coli was used to investigate the relation between metabolic and physiological effects of adrenaline. Electrical and mechanical activity was recorded with the sucrose gap technique and, in parallel experiments, the concentration of energy-rich phosphate compounds, adenosinetriphosphate and creatine phosphate, (ATP and CP) in the tissue was determined.2. Adrenaline (in concentrations from 2 x 10-9 g/ml. to 5 x 108 g/ml.) increased the tissue content of energy-rich phosphate compounds. This effect was coincident with the physiological, inhibitory effect on electrical and mechanical activity.3. After anaerobic exposure of the tissue to substrate-free medium, the biochemical and the physiological effects ofadrenaline were both abolished; both recovered after readmission of oxygen and/or substrate.4. In muscles depleted of glycogen in substrate-free medium, either by anoxia or by high temperature, adrenaline produced its stabilizing effect on the cell membrane and the increase in ATP and CP content when ,6-hydroxybutyrate was the substrate, i.e. in the complete absence of carbohydrate from the medium and from the tissue.5. When adrenaline was applied simultaneously with the readmission of substrate, the ATP and OP content of pieces treated with adrenaline was greater than of control pieces, though the tension of both was zero. This indicates that the effect was not secondary to the muscle relaxation but was the result of increased ATP synthesis.6. The physiological and biochemical effects of adrenaline were both abolished by the same concentration of imidazole (0.05 M).E. BUEDING AND OTHERS 7. Low concentrations of ATP (1 x 106-5 x10-6M)-like adrenalineinhibited electrical and mechanical activity of the taenia. This effect was also abolished by imidazole.

show abstract

444 Dissociation of the augmentation of cardiac contractile force from the activation of myocardial phosphorylase by catecholamines

Cited by 21 publications

References 0 publications

Influences of Corticosteroids on Cardiac Glycogen Concentration in the Rat

Influences of Corticosteroids on Cardiac Glycogen Concentration in the Rat

The effect of noradrenaline on the permeability of depolarized intestinal smooth muscle to inorganic ions

The effect of adrenaline on the adenosine otriphosphate and creatine phosphate content of intestinal smooth muscle

Contact Info

Product

Resources

About