Perspectives on Research in Emotional Stress

Detlev Ganten, Nicola A. Nikolov, K.V. Sudakov

• Publisher: Routledge
• Year: 2022
• Print ISBN: 9782881246999
• eBook ISBN: 9781134305858
• Edition: 1
• Topic: Medicine
• Subtopic: Health Care Delivery

First Published in 1989. Based on the updated proceedings of the Soviet-American International Pavlovian Conference held in Moscow, this volume presents a new trend in the systems analysis of emotional stress as an outcome of behavioural conflict situations in which the subjects fail to achieve a useful end result. The mechanisms, complications, prevention and behavioural therapy of emotional stress are examined. While almost any of the body functional systems can be involved, psychosomatic and immune system disorders, coronary heart diseases and hypertension are shown to be the major complications of chronic exposure to emotional stress in both humans and animals. A special section of the book highlights various approaches towards the enhancement of stress resistance in man through emotional self-regulation, relaxation, social skills training and other biobehavioural interventions.

PART I

SUSCEPTIBILITY AND RESISTANCE TO EMOTIONAL STRESS: CENTRAL MECHANISMS

STABILITY OF PHYSIOLOGICAL FUNCTIONS IN EMOTIONAL STRESS: NEUROCHEMICAL DATA

T. I. BELOVA

P. K. Anokhin Institute of Normal Physiology, USSR Academy of Medical Sciences, Moscow 103009, USSR

Abstract

The systems approach to the origins of emotional stress and the related cerebrovisceral dysfunctions has raised the issue of neurochemical mechanisms governing the stability of physiological functions in experimental emotional stress. Data are presented on changes in catecholamine content, the activity of monoamine oxidase, acetylcholinesterase, choline acetyltransferase, and the permeability of the blood-brain barrier (BBB) in brain nuclei of animals differing in dynamics of blood pressure (BP) and state of gastric mucosa under stress. The implication of the locus coeruleus in BP regulation and BBB permeability in emotional stress is shown in rats. The involvement of cholinergic mechanisms of rabbits’ hypothalamic perifornical area in behavior engendered by negative emotion is also demonstrated.

Contents

1. Introduction

2. Materials and Methods

3. Results

4. Discussion

1. INTRODUCTION

P. K. Anokhin’s theory of functional systems proposed in 1935 (1) defined a new approach to studies in the origins of emotional stress and the related cerebrovisceral disorders. Emotional stress developing in conflict situations is a biologically founded, rational response of a system leading to a useful result. But protracted or persistent negative emotional arousals can cause general activation of brain structures and have a pathogenic impact on central mechanisms of somatic and visceral functions. Thus, emotional stress initiates a state of changed relationship between the cortex and the subcortex. As it is inseparable from changed brain activity and somatoautonomic disorders it can be described as dynamic cerebrovisceral "emotional stress syndrome" (2).

Obviously this suggests that autonomic manifestations of emotional stress are caused by the primary brain structure responses. Therefore, studies in neurochemical processes under stress should be central in elucidating the mechanisms behind cerebrovisceral disorders in negative emotional states.

The systems approach to the problem implies inter alia specific comparison of neurochemical changes and the dynamics of physiological functions. This raised the issue of the stability of physiological functions in emotional stress (2).

This paper presents the main results of studies on neurochemical conditions maintaining self-regulation of physiological functions in emotional stress.

2. MATERIALS AND METHODS

Emotional stress was induced in immobilized male Chinchilla rabbits by unilateral aperiodic stimulation of the negative emotional hypothalamic centers (the ventromedial nuclei) and stochastic electrocutaneous stimulation. The duration of the stimulus was 10-30 s during a 3-h experiment. The parameters of electrical ventromedial hypothalamic and electrocutaneous stimulation were selected to raise blood pressure (BP) by 20-30 mm Hg, but not to cause marked motor activity in each individual animal.

The animals were divided into two groups according to BP changes: resistant and predisposed to cardiovascular disorders. Relatively stable mean BP was typical of the resistant group. Progressive BP decrease was observed in the predisposed group with a fatal outcome 2 h 15 min - 2 h 50 min after the beginning of the experiment. A total of about 80 rabbits was used in control and experimental groups of each series consisting of 5-7 animals each.

Adult male rats of different strains (Wistar, August - for catecholamine studies; Sprague-Dawley - for histochemical analysis of catecholamines and blood-brain barrier (BBB) permeability) were immobilized on a board for 6.5 h with rigid fixation of paws and head (3). Tentative studies proved this period was sufficient to reveal major BP changes. Immediately before immobilization with the rats at rest in cages, and every hour during immobilization BP was recorded via polyethylene catheter implanted into the tail artery of Wistar and August rats or into the descending aorta of Sprague-Dawley rats.

Depending on the BP dynamics during immobilization rats were divided into groups. Wistar Group 1, BP increase by 20 mm Hg or more; Group 2, relatively stable BP (the increase not exceeding 15 mm Hg); Group 3, BP decrease. August rats did not show BP decrease during immobilization. Therefore, August rats were divided into two groups: Group 1 with BP increase by 20 mm Hg or more, and Group 2 with relatively stable BP. There were three subgroups in August Group 1: Group la with BP increased by 45 mm Hg or higher; Group lb with a less abrupt BP increase (by 30-45 mm Hg); and Group 1c with BP increase up to 30 mm Hg.

A total of 100 animals were used for the experiments. Control and experimental groups of each series consisted of 5-7 rats each. Rats kept under the same conditions in cages served as controls.

At the end of the experiment the animals were decapitated, the brains quickly removed and frozen on CO₂ ice (or in liquid propane-propylene for investigation by Falck-Hillarp technique). Gastric mucosa was analyzed for the presence of ulcers or hemorrhages using a low power microscope. Neurochemical changes were assessed individually and in small groups of animals sharing similar BP dynamics or similar state of gastric mucosa. The Falck-Hillarp technique (4, 5) and its modification (6) was employed for histochemical analysis of catecholamines (CA). Quantitative analysis was performed on a fluorescence microscope Lumam I-3 (LOMO, USSR) with a photometer. Radioenzyme technique was used for CA determination (epinephrine (E), norepinephrine (NE), dopamine (DA) separately) in various brain nuclei (7, 8). Nuclei and cell groups were is...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Introduction to the Series
• Preface
• Part I. Susceptibility and Resistance to Emotional Stress: Central Mechanisms
• Part II. Emotional Stress and Psychosomatic Disorders
• Part III. Biobehavioral Prevention and Therapy of Stress-Induced Disease
• Part IV. Coronary Heart Disease, Hypertension and Stress
• Subject Index