What does alpha-2 do to the heart?
The sympathetic nervous system is the part of the nervous system that increases heart rate, blood pressure, breathing rate, and pupil size. When alpha-2 receptors are stimulated, sympathetic nervous system activity decreases. This decreased sympathetic activity leads to a drop in blood pressure and heart rate.
What does alpha-2 activation do?
Activation of prejunctional α2-autoreceptors on sympathetic neurons results in a sympatholytic action. α2-Adrenoceptors are also present at postjunctional sites, where they mediate actions such as smooth muscle contraction, platelet aggregation, and inhibition of insulin secretion.
Does Alpha-2 increase heart rate?
The typical cardiovascular response to the administration of alpha2 agonists is biphasic. Initially, blood pressure and systemic vascular resistance increase, whereas heart rate and cardiac output decrease.
What are alpha-2 antagonists used for?
Alpha-2 antagonist antidepressants are medications prescribed to treat depression. Alpha-2 agonist antidepressants work on the central nervous system to increase the levels and modulate the activity of norepinephrine and serotonin, chemical messengers (neurotransmitters) released by nerve cells (neurons).
What does alpha 2 do to blood vessels?
Constriction of some vascular smooth muscle. Venoconstriction of veins.
Does alpha-2 decrease insulin?
α(2)-Adrenoceptor antagonists increase insulin secretion and reduce blood glucose levels by inhibiting tonically active α(2A)-adrenoceptors on pancreatic β-cells, but may also enhance sympathoadrenal output.
What does alpha-2 receptors do in blood vessels?
The alpha 2-adrenergic receptors, like alpha 1-receptors on vascular smooth muscle, serve an important role in the control of the arterial, as well as the venous tone in experimental animals and humans in relationship to sympathetic and humoral adrenergic activation of the cardiovascular system.
What does the beta-2 receptor do?
Stimulation of these receptors causes smooth muscle relaxation, which may result in peripheral vasodilation with subsequent hypotension and reflex tachycardia. Stimulation of beta-2 receptors in the lungs causes bronchodilation, the desired clinical effect.