Cardiac epinephrine synthesis.

Cardiac Epinephrine Synthesis

Background. The heart can synthesize epinephrine. Homogenates of rat heart, which contain the enzymes phenylethanolamine N-methyltransferase (PNMT) and nonspecific N-methyltransferase (NMT), methylate norepinephrine to form epinephrine. The cardiac atrium contains primarily PNMT and the cardiac ventricle contains both PNMT and NMT. Methods and Results. Rats were given the glucocorticoid dexamet...

Cardiac epinephrine synthesis and ischemia-induced myocardial epinephrine release.

OBJECTIVE Phenylethanolamine-N-methyltransferase (PNMT), the enzyme that synthesizes epinephrine (EPI) from norepinephrine (NE) in the adrenal gland, is present in extra-adrenal tissues including heart. Ischemia evokes an excessive NE accumulation in the myocardial interstitial spaces. Therefore, cardiac PNMT activity with high NE levels may contribute to cardiac EPI synthesis and release evoke...

Rat renal epinephrine synthesis.

Rats that underwent adrenal demedullation had a 93% decrease in plasma epinephrine (E) levels, but did not decrease their renal E. Even further treatment with 6-hydroxydopamine and reserpine failed to lower renal E levels. Similarly, urine E levels failed to decrease after adrenal demedullation and renal denervation. There is a renal E-synthesizing enzyme that differs from adrenal phenylethanol...

Adrenocortical control of epinephrine synthesis.

Factors Modifying Cyclopropane-Epinephrine Cardiac Arrhythmias

WE HAVE reported that the minimal cardiac arrhythmia due to epinephrine in cyclopropane-anesthetized dogs is a coupled, usually bigeminal rhythm which exhibits a remarkably constant interval between the normal and the abnormal beats. This arrhythmia is elicited only by the simultaneous presence of a sympathomimetic amine with cardiac actions and a critical systemic blood pressure, which is char...