ABSTRACT
This chapter focuses on the in vivo, conscious rat methods used in the studies to examine the influence of biogenic amines on neuroendocrine functions. It reviews of the role of monoamines in the regulation of the hypothalamic-pituitary-adrenocortical (HPA) axis will be given and deals with physiological and methodological aspects related to the disagreements. The HPA axis plays a key role in the integration of the responses to stress through effects on homeostatic mechanisms. Several studies have shown a stimulatory role of catecholamines on the activity of the HPA axis. The hormonal message and its final action depend on a complex machinery. Several studies use single point hormone measures instead of time course based on serial blood samples to characterize neuroendocrine responses. One of the most important physiological regulatory systems of the activity of HPA axis is the glucocorticoid negative feedback. In fact, these feedback effects are very strong, multiphasic and usually quantitatively more prominent than any other physiological inputs.
