The influence of age and functional neuropsychiatric disorders on sympathetic and parasympathetic functions

Abstract

THAT changes, due to ageing, occur in the central nervous system in general and in the autonomic system in particular has been known since CHARCOT’S lectures (1881). From physiologic measurements of blood sugar, temperature and acid base balance, as well as adaptation of the circulatory and respiratory system to emergencies, CANNON (1942) stated that the preservation of stability is impaired and homeostasis is maintained within a narrower range in the aged. Agreement with this statement is found in other studies. NORRIS et al. (1953) demonstrated a slower compensatory response in the systolic and diastolic blood pressure of older people when subjected to tilting from the horizontal and vertical planes. Older subjects have also shown a distinct decline in pulse rate reaction following atropine injection (CRAWFORD, 1924), along with a significant depression in tolerance to intravenous glucose (SCHNEIBERG and FINESTONE, 1952) when compared with younger subjects. Experimental studies in animals have presented evidence of decline in function of the autonomic nervous system. In older rats, SAFFORD and GELLHORN (1945) found a diminished excitability of the sympathetico-adrenal system when measured by the blood sugar response to anoxia, and FRIEDMAN et al. (1956) reported a decline in neurohypophyseal function. Histopathologic studies have supported the physiologic evidence of autonomic nervous system changes secondary to age. KUNTZ (1938) found a progressive change in dendrites, a reduction in chromidial substance, and a deposition of melanotic pigment in autonomic ganglion cells associated with age. The deposition of pigment, felt by CRITCHLEY (1942) to be the most important change, was least obvious in the hypothalamus. Recently, however, ANDREW (1956) in an extensive study of structural alterations with ageing, has stated that the nuclei of the hypothalamus show perhaps the most impressive and striking incidence of specificity of age-change seen anywhere in the nervous system. He found an increase in cellular size to giant cell proportions, 8-10 times as large as comparable cells in younger individuals. There were multinucleate cells. The nucleolus showed multiple divisions and there was an increase in basophilic properties. These changes were felt to be a defensive reaction to ageing