Catecholamines Levels in the Rat Brain and Plasma during Cardiac Arrest and after Resuscitation

Abstract

The catecholamines (CAT) dopamine, norepinephrine and epinephrine are neuro-transmitters and/or hormones in peripheral tissues and central nervous system (CNS). Norepinephrine is the principal postganglionic, sympathetic neurotransmitter in both periphery and CNS. Epinephrine formed by the N-methylation of norepinephrine, is a hormone released from the adrenal gland, and it stimulates CAT receptors in a variety of organs. Small amounts of epinephrine are also found in the CNS, particularly in the brain stem. The enzymatic processes involved in the formation and metabolism of CATs have been more completely characterized than those for any other neurotransmitter (1). The literature concerning disorders of CAT metabolism in hypoxia and ischemia can be divided into three groups: papers describing disorders of their metabolism in the brain, in the blood, and relation of CAT metabolism in the brain to the activity of adenylate cyclase. To the first group belong studies on the endogenous CAT level in the brain under influence of hypoxia and ischemia (2-8); the relationship between CATs and blood-brain barrier (BBB) in ischemia (9); and the relationship between monoamines and brain energy metabolism in ischemia (7). To the second group belong studies on changes of CAT concentration in the peripheral blood in ischemia (10-12) and their effect on modulation of postischemic brain damage (13). The third group presents studies on CAT effect on adenylate cyclase activity in normal and ischemic conditions (9,14-17). The aim of this study was to evaluate concentration of norepinephrine and epinephrine in the rat brain and plasma during cardiac arrest and after resuscitation.