Effects of cyclopropane on catecholamine release from bovine adrenal medulla

The direct effects of cyclopropane on both adrenal medullary release of catecholamines and release of catecholamines from isolated chromaffin granules were examined. Cyclopropane had no effect on the spontaneous release of catecholamines from perfused bovine adrenals, while it reversibly inhibited carbachol-induced release of catecholamines in a dose-dependent manner. At 20 per cent cyclopropane, catecholamine release was reduced to 52 per cent of control. Cyclopropane exerted no action on spontaneous release or Mg++-ATP-dependent release of catecholamines from isolated chromaffin granules. Thus, the authors conclude that the direct action of cyclopropane on the adrenal medullary release of catecholamines is inhibitory, and that chromaffin granules are not the site of action of this anesthetic.