Zum Mechanismus der durch Calcium und Magnesium verursachten Freisetzung der Nebennierenmarkhormone

The effects of alkaline earths and other divalent cations on adrenal medullary secretion

“…As we have previously pointed out, the concentration of Ca required in their experiments to release catecholamines from the granules in vitro was considerably higher than one might expect ever to find in the cell sap; and its stimulant effects on the granules were very small in comparison with those we have observed in the intact gland. The present results with magnesium give further reason to be cautious in accepting the catecholamine granules in vitro as a model of the Casensitive mechanism involved in adrenal medullary secretion, for Schumann & Philippu (1963) found that magnesium also was effective in increasing the rate at which the granules released catecholamines. This is in striking contrast to the purely inhibitory effects of magnesium we have observed in the intact gland.…”

Reduction of Increased Vascular Permeability by Calcitonin

“…Among such factors affected by moderate changes in available calcium, the catecholamines are of particular interest. There is ample evidence that their release is triggered by calcium in opposite directions depending on the organ involved [14,17]. If a lowering of serum calcium leads to an en hanced release of catecholamines, for instance in the microcircu lation as it does in the cat iris [17], the anti-inflammatory effect of calcitonin might be ascribed to such a mechanism involving catecholamines.…”

Evidence for Participation of Catecholamines in Cardiac Action of Ouabain: Positive Chronotropic Effect

“…the interaction with catecholamines and the mobilization of calcium, are merely occurring simultaneously or whether one triggers the other. The pursuit of this idea is of interest because, on one hand, calcium is able to enhance the release of catecholamines (Schumann & Philippu, 1963;Katz & Kopin, 1969;Philippu, Heyd & Burger, 1970), and, on the other, catecholamines increase the transmembrane exchange of calcium (Reuter, 1967). The former seems unlikely since chronotropic changes produced by calcium are not influenced by antiadrenergic drugs (Seifen et al, 1964a;Schaer, 1968).…”

“…This factor could be that cardiac glycosides increase the readily exchangeable intracellular calcium fraction (Klaus & Kuschinsky, 1962;Lfillmann & Holland, 1962). Calcium has been shown to enhance pacemaker activity in isolated heart preparations (Reiter & Noe, 1959;Seifen et al, 1964a;Seifen et al, 1964b;Schaer, 1968;Seifen, 1968b). These observations make it very tempting to consider calcium mobilization as the second factor contributing to the positive chronotropic effect of ouabain in the guinea-pig isolated atrium.…”

“…Cardiac glycosides have been reported to increase the intracellular, freely exchangeable calcium, i.e., 'mobilize' calcium (Klaus & Kuschinsky, 1962;Liillmann & Holland, 1962). It is also known that calcium shortens the cycle length in guinea-pig atria (Schaer, 1968;Seifen, 1968b), and in other species (Reiter & Noe, 1959;Seifen, Flacke & Alper, 1964a;Seifen, Schaer & Marshall, 1964b).…”