Activity and Thermosensitivity of Canine Cutaneous Veins after Inhibition of Monoamine Oxidase and Catechol-O-Methyl Transferase
The lateral saphenous vein of the dog was perfused with homologous blood at constant flow. Changes in driving pressure were used to measure active changes in venous tone. Administration of tranylcypromine greatly reduced the activity of monoamine oxidase in the vein and increased its response to electric stimulation of the lumbar sympathetic chain and to norepinephrine infusions. Administration of pyrogallol (a catechol-O-methyl transferase inhibitor) also increased the response of the vein to adrenergic stimulation. These chemicals did not alter the increase in the sensitivity of the venous smooth muscle to sympathetic nerve impulses and infused norepinephrine produced by cooling the perfusate. Thus, the potentiating effect of local cooling on the response of the cutaneous veins to adrenergic stimulation cannot be explained by interference with the local enzymatic inactivation of catecholamines.
- catecholamine inactivation
- local temperature and venous reactions
- increased venous response to adrenergic stimulation
- monoamine oxidase in veins
- Received March 13, 1969.
- Accepted September 4, 1969.
- © 1969 American Heart Association, Inc.