Brain Catecholamines, Serotonin, and Gamma-Aminobutyric Acid and Adrenal Catecholamines After High Spinal Cord Transection in the Rat

Abstract

In this communication, subacute alterations in whole brain concentrations of the putative neurotransmitter substances, dopamine (DA), norepinephrine (NE), serotonin (5-HT), and gamma-aminobutyric acid (GABA), and of adrenal medullary catecholamines (CA) as a result of complete transection of the spinal cord at the C-7 level are described. A number of new studies have shown changes in neurotransmitter substances in the spinal cord, both in the area of injury (Naftchi et al., 1974) and in the spinal cord segments proximal and distal to the injury (Magnusson, 1973; Naftchi et al., 1972, 1973). The study by Magnusson showed that over the long term the monoamines decreased below the level of the transection (mid-thoracic) and increased above. The latter increase was considered to represent increased metabolic activity in the remaining proximal portions of the monoamine pathways. Monoamine decreased metabolic activity distal to spinal cord transection may also be reflected in decreased CA turnover in the sympathoadrenal system (Snider and Carlsson, 1972).