There are many notable differences between alpha and beta-adrenergic receptors. Beta receptors do the opposite of alpha-receptor activities.
Generally, epinephrine has a higher affinity for alpha receptors. Alpha receptors also tend to provide negative feedback and thus reduce adrenergic effects. This is why alpha-agonists lower bloodpressure. Norepinephrine has a higher affinity for beta receptors.
Alpha receptors often cause contraction of blood vessels (arterioles, arteries, and significant veins) while beta receptors cause dilation of blood vessels. Generally, alpha cells stimulate effector cells, and beta receptors relax effector cells. However, when it comes to the heart, beta-agonist stimulate the heart rather than causing relaxation.
F. Daniel, Content Optimization Executive, Diploma in Journalism, California
Answered on Jul 16, 2019
Adrenergic receptors, being a kind of protein, helps to regulate our responses to fight-or-flight syndrome, which is a physiological reaction that occurs whenever one has a terrifying or stressful experience. This adrenergic receptor is of two major types, those are the alpha receptors and beta receptors. Alpha 1 and alpha 2 are the two significant types of alpha receptors; while beta 1, beta 2, and beta 3 are the three significant types of beta receptors. These receptors can be found at the sympathetic junctions of various organ, are located postsynaptically.
These receptors can also be found in the heart, airways, fatty tissues, blood vessels, uterus, and several other areas. Mostly, alpha receptors are involved in the constriction of blood vessels and the stimulation of effector cells. Beta receptors, on the other hand, are usually engaged in the dilatation of blood vessels and relaxation of effector cells. Better receptors make our heart beats faster and with force when the heart organ is affected.