Encyclopedia > Adrenergic receptor

  Article Content

Adrenergic receptor

An adrenergic receptor is a cell membrane protein, that reacts to adrenaline and noradrenaline (also called epinephrine and norepinephrine).

Many cells possess these receptors, and the binding of an agonist[?] will generally cause the cell to respond in a flight-fright type way. For instance the heart will start beating quicker and the pupil will dilate.

There are several types of adrenergic receptors, but there are four main groups:

Table of contents

Alpha-1 receptors In blood vessels these cause vasocontriction.

Alpha-2 receptors When an agonist binds to an α2-receptor, cyclic AMP levels within the cell decrease. These are found on pre-synaptic nerve terminals.

Beta-1 receptors These are present in heart tissue, and cause an increased heart rate by acting on the cardiac pacemaker cells. A good beta-blocker for treatment of angina will only affect these receptors and not the beta-2 receptors.

Beta-2 receptors These are in the vessels of skeletal muscle[?], and cause vasodilation, which allows more blood to flow to the muscles, and reduces total peripheral resistance. These tend to work with adrenaline, but not noradrenaline.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Brazil

... powers to the federal government, of which the president and vice president are elected on the same ticket by popular vote for four-year terms. The president ha ...

 
 
 
This page was created in 25.3 ms