What is vasoconstriction and is there a treatment?

Answer

vasoconstriction is when some blood vessels (arteries, arterioles, etc) constrict and essentially increase the impedance to blood flow. This is known as vascular resistance, and is a major contributor to blood pressure (hypertension).

Blood vessels are usually in a state of relative constriction, but can constrict further in respone to cold (thermoregulation), to low blod volume or low blood pressure (shock/maintaining a normotensive state/maintaining perfusion pressure) or to signals from the nervous system, which can be replicated by the administration of drugs (e.g. adrenalin).

Treatment for vasoconstriction would include the use of vasodilators- alpha adrenoceptor antagonists, or calcium-channel blockers. The latter group of drugs is often used in the treatment of hypertension.