Vasomotoros

Vasomotoros, in a physiology context, refers to the systems and mechanisms that regulate the diameter of blood vessels and thus vascular tone. The term is sometimes used interchangeably with vasomotor or vasomotor function, and it encompasses neural, hormonal, and local factors that control blood flow and blood pressure through constriction or dilation of vessels.

The core components are vascular smooth muscle, the autonomic nervous system, and endothelial signaling. Sympathetic postganglionic nerves release norepinephrine that primarily acts on alpha-1 adrenergic receptors to produce vasoconstriction, increasing vascular resistance. In some tissues, other pathways can promote vasodilation, such as beta-adrenergic effects in skeletal muscle or nonadrenergic mechanisms involving nitric oxide from the endothelium. Endothelial cells also release vasodilators (e.g., nitric oxide, prostacyclin) and vasoconstrictors (e.g., endothelin), modulating local tone. Local metabolic factors, including carbon dioxide, oxygen, pH, and temperature, can adjust vessel diameter independently of central command, a process known as autoregulation.

Central control is provided by the vasomotor center in the medulla oblongata, which integrates baroreceptor and chemoreceptor input and modulates sympathetic outflow via spinal pathways. Higher brain regions can influence vascular tone in situations such as stress or thermal regulation. Hormonal signals, including circulating catecholamines and renin–angiotensin system components, also influence vasomotor activity.

Clinical relevance includes disorders of blood pressure regulation (hypertension, orthostatic intolerance), Raynaud phenomenon, and vasomotor symptoms related to menopause, where central thermoregulatory changes lead to peripheral vasodilation and heat loss. The term vasomotoros is less common in English and may appear as a variant of vasomotor factors in some languages.