Adrenal Chromaffin Cell Function under

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(1) Uptake of [3H]dopamine in isolated chromaffin cells of mice.The adrenal glands of the mouse were isolated and the cortex was removed. The adrenal medulla was digested by collagenase. Isolated chromaffin cells were incubated in the medium containing certain substance which is considered to be secreted under stress. The uptake of [3H]dopamine was inhibited by bardykinin, angiotensin II, neurotensin, VIP and substance P. These substances are considered to inhibit catecholamine uptake to extend the biological action of catecholamines secreted under stress.(2) Effect of stress on the uptake of [3H]dopamine and [3H]leucine in vivo.Mice were exposed to immobilization stress for 2 h. [3H]dopamine was injected i. p. and after a certain period, the adrenal glands of mice were processed for autoradiography. The uptake of dopamine was inhibited by stress and the inhibition was prevented by adrenal denervation. This result may indicate that stress increased sympathtic nerve activity to the adrenal gland and inhibited catecholamine uptake to extend the action of catecholmaines.The uptake of [3H]leucine was increased by stress. Adrenal denervation inhibited the uptake. Constituents of chromaffin granules such as amino acids like leucine will be lost during exocytosis. Thus the enhancement of leucine uptake is considered to replace the lost constituents.