Beta adrenergic agonists or beta agonists are drugs that relax the muscles of the airways, which widen the airways and produce easier breathing. They are sympathomimetic agent classes acting on the adrenoceptor beta. In general, pure beta-adrenergic agonists have opposite functions of beta blockers. Leta agonist adrenoceptor ligands mimic the action of epinephrine and norepinephrine signaling in the heart, lungs, and smooth muscle tissue, with epinephrine expressing the highest affinity. Activation? 1 ,? 2 and? 3 activates enzyme, adenylate cyclase. This, in turn, leads to activation of the cyclic adenosine monophosphate (cAMP) secondary enema, cAMP then activates protein kinase A (PKA) which phosphorylates the target protein, ultimately inducing smooth muscle relaxation and contraction of cardiac tissue.
Video Beta-adrenergic agonist
Function
Activation of receptor 1 induces positive inotropic chototropic output of the heart muscle, leading to an increase in heart rate and blood pressure, ghrelin secretion from the stomach, and renin from the kidneys.
Receptor activation 2 induces relaxation of smooth muscle in the lungs, gastrointestinal tract, uterus, and various blood vessels. Increased heart rate and heart muscle contractions are also associated with receptor 2.
? 3 receptors are primarily located in adipose tissue. Receptor activation " 3 induces lipid metabolism.
Maps Beta-adrenergic agonist
Medical use
Indication of administration for? agonists include:
- Bradikardia (slow heart rate)
- Asthma
- Chronic obstructive pulmonary disease (COPD)
- Heart failure
- Allergic reactions
- Hyperkalemia
- Beta blocker poisoning
- Preterm labor (this is off-label use and can be harmful) & lt; https://www.fda.gov/Drugs/DrugSafety/ucm243539.htm>
Side effects
Although small compared to epinephrine, beta agonists usually have mild to moderate side effects, which include anxiety, hypertension, increased heart rate, and insomnia. Other side effects include headaches and essential tremors. Hypoglycemia is also reported because of increased insulin secretion in the body from activation of receptor 2 .
In 2013, zilpaterol, a? agonists sold by Merck, are temporarily withdrawn because of signs of disease in some of the animals fed on the drug.
Receptor selectivity
Most beta-receptor agonists are selective for one or more beta-adrenoreceptors. For example, patients with low heart rates are given more "selective cardio" beta agonist treatments such as dobutamine, which increases the strength of cardiac muscle contractions. Patients suffering from chronic inflammatory lung diseases such as asthma or COPD are treated with salbutamol (albuterol), which primarily induces relaxation of smooth muscle in the lungs and reduces cardiac contraction.
? 3 agonist is currently in clinical research and is thought to increase lipid cleavage in obese patients.
? 1 agonist
? 1 agonists stimulate adenylyl cyclase activity and calcium channel opening (cardiac stimulation, used to treat cardiogenic shock, acute heart failure, bradyparithmia). The selected example is:
- Denopamine
- Dobutamine
- Dopexamine (? 1 and? 2 )
- Epinephrine (not selective)
- Isoprenaline (INN) , isoproterenol (USAN) (? 1 and? 2 )
- Prenalterol
- Xamoterol
? 2 agonist
? 2 agonists stimulate adenylyl cyclase activity and close the calcium channel (smooth muscle relaxants used to treat asthma and COPD). The selected example is:
Not specified/sorted
These agents are also listed as agonists by MeSH.
See also
- alpha-adrenergic agonist
References
Source of the article : Wikipedia
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