The projections of the ventral tegmental area and adjacent regions: A combined fluorescent retrograde tracer and immunofluorescence study in the rat

Ventral tegmental (A10) system: neurobiology. 1. Anatomy and connectivity.

Physiopharmacological interactions between stress hormones and central serotonergic systems

Differential effects of inescapable footshocks and of stimuli previously paired with inescapable footshocks on dopamine turnover in cortical and limbic areas of the rat

Aversive experiences have been thought to provoke or exacerbate clinical depression. The present review provides a brief survey of the stress-depression literature and suggests that the effects of stressful experiences on affective state may be related to depletion of several neurotransmitters, including norepinephrine, dopamine, and serotonin. A major element in determining the neurochemical changes is the organism's ability to cope with the aversive stimuli through behavioral means. Aversive experiences give rise to behavioral attempts to cope with the stressor, coupled with increased utilization and synthesis of brain amines to contend with environmental demands. When behavioral coping is possible, neurochemical systems are not overly taxed, and behavioral pathology will not ensue. However, when there can be no behavioral control over the stressful stimuli, or when the aversive experience is perceived as uncontrollable, increased emphasis is placed on coping through endogenous neurochemical mechanisms. Amine utilization increases appreciably and may exceed synthesis, resulting in a net reduction of amine stores, which in turn promotes or exacerbates affective disorder. The processes governing the depletions may be subject to sensitization or conditioning, such that exposure to traumatic experiences may have long-term repercussions when the organism subsequently encounters related stressful stimuli. With continued uncontrollable stimulation, adaptation occurs in the form of increased activity of synthetic enzymes, and levels of amines approach basal values. It is suggested that either the initial amine depletion provoked by aversive experiences or a dysfunction of the adaptive processes, resulting in persistent amine depletion, contributes to behavioral depression. Aside from the contribution of behavioral coping, several organismic, experiential, and environmental variables will influence the effects of aversive experiences on neurochemical activity, and may thus influence vulnerability to depression.

Depression: The predisposing influence of stress

Effects of stress on the metabolism of noradrenaline, dopamine and serotonin (5HT) in the central nervous system of the rat. (II). Modifications of serotonin metabolism.

Anne Marie Thierry

Papers

Effects of stress on the metabolism of noradrenaline, dopamine and serotonin (5HT) in the central nervous system of the rat. (II). Modifications of serotonin metabolism.

Demonstration of horseradish peroxidase and fluorescent catecholamines in the same neuron