Abstract
Summary
Prolonged isolation stress of rats was associated with a significant diminution of myocardial potassium and magnesium, and with a marked increase in myocardial sodium, causing a reduction of the K/Na ratio. Restoration of contact with other animals tended to correct these changes within a short period of time. Myocardial calcium was increased during isolation. Histochemical and histological observations revealed a marked aggravation of epinephrine-induced myocardial focal potassium displacement, and the appearance of epinephrine-induced hemorrhages and necroses in the hearts of isolated rats, which could not be elicited in the controls by analogous doses of epinephrine. This type of augmented vulnerability of the heart muscle to catecholamine action is attributed to the well-established principle of exaggerated catecholamine cardiotoxicity under corticoid over-action, in view of the fact that others have observed an increased corticoid production in isolated rats.
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