[Noise: neuro-endocrine aspects]

Experimental study of neuro-endocrinological effects of noise stress shows neuro-mediator modifications. Exposure to stress induces a marked stimulation of the adrenergic structures which increases plasma concentrations of ACTH and glucosteroids. The increased secretion of the cortico-releasing factor (CRT) from the hypothalamo-hypophyseal system mediates a complex cascade in which other neuro-modulators also participate. Within the CNS, CRF activates the sympathetic nervous system, raising plasma concentrations of epinephrine and nor-epinephrine. These neuro-mediator and endocrine variations modify the activity of central nervous structures, mainly hypothalamic (endocrine) and hippocampic (emotion) formations, inducing many homeostatic perturbations. Stress also causes marked alterations in the immune function. In chronically noise-stressed patients, a comparative clinical study showed a significant increase of the plasmatic STH, but no modification of others biological parameters. Some psychosomatic disorders and also a psychological unbalance were seen in these patients. The final response to a stressful event will either be no or certain specific chemical and physiological changes which will depend greatly on the ability of the individual to cope with the outside stimuli.