[The brain catecholamines: brief anatomy and participation in the stress reaction and regulation of cardiovascular...

Catecholamines (norepinephrine, dopamine, epinephrine) act in the brain as chemical neurotransmitters and represent integrative component of many anatomical and functional interrelationships, which play important role in the maintenance of the basic physiological processes and homeostasis of living organism. In the brain, several well circumscribed conglomerations of catecholaminergic neurons and dopaminergic and noradrenergic pathways can be recognized. Although they are represented by only a few thousands of catecholaminergic neurons (in rat about 5) located only in certain brain areas, their rich arborization provides extensive innervation over the whole brain. Catecholamines are significantly involved in conveying of viscero- and somato-sensitive signals to integrative centrers located in higher brain areas and participate in the regulation of all vitally important systems under basal conditions as well as during stress. Their normal physiological activity is important for the maintenance of healthy functioning of the organism. Brainstem aggregations of catecholaminergic neurons, localized predominantly in autonomic regions, are involved in conveying the afferent peripheral stress and cardiovascular signals. The hypothalamic paraventricular nucleus, which represents an integrative center of the stress response, receives a rich catecholaminergic innervation from the caudal brain. On the other hand, catecholaminergic neurons localized in the ventrolateral rostral medulla form an important component of circuits involved in the regulation of the cardiovascular system. Central catecholamines are also involved in many other important brain circuits, however, with respect to the limited space of this review, they could not be included.