In the vascular system it cause beta mediated vasodilation. Beta blockers have negative inotropic and chronotropic effects which make it useful drugs for patients with angina chronic heart failure. It might be due to the effects on heart and blood vessels, suppression of the renin-angiotensin system and effects in the central nervous system. When beta blockers inhibits beta receptors, it decreases blood pressure in patient with hypertensions. However beta blockers also possess partial agonist activity and local anesthetic action which differ among the beta blockers. The major effects of beta blockers is the beta receptor blockage. Smooth muscles dilation, potassium uptake from skeletal muscles, activates glycogenolysis. Respiratory, urinary and smooth muscles, skeletal muscles, liver Platelets aggregation, contraction, inhibition of lipolysis and neuro-transmitter release Postsynaptic CNS adrenoceptor, platelets, adrenergic and cholinergic nerve terminals, smooth vascular muscles, fat cells Most vascular smooth muscles, papillary dilator muscles, prostate and heartĬontraction, pupillary dilation, increase force of contraction of heart DISTRIBUTION OF ALPHA AND BETA RECEPTORS SUBTYPES IN THE BODY Type Dopamine receptors is selective for dopamine produce in the body. MECHANISM OF ACTION Adrenoceptors and its presence in the bodyĪdrenoceptors are broadly classified in three types, alpha, beta and dopamine receptors.Īlpha and beta receptors are divided on the basis of potencies towards endogenous catecholamines such as alpha receptors have potencies epinephrine > norepinephrine > isoproterenol while beta blockers has vice versa isoproterenol > norepinephrine > epinephrine. Selective β 1, blocker with additional vasodilation activity Non-selective, both α and β blockers with additional vasodilation activity
Selective β 1, also called cardio selective Non-selective, acts on β 1 and β 2 receptors Beta blockers can also be divided in generations which is following nowadays. TYPES OF BETA BLOCKERSīeta blockers can be classified according to α or β receptor selectivity or both. Some beta blockers are also used in other clinical conditions such as migraine prophylaxis and glaucoma. hypertension, heart failure, cardiac arrhythmias. This is why beta blockers are useful in treatment of cardiovascular diseases i.e. This action leads to decrease sympathetic effects mainly on cardiovascular system. Beta blockers are competitive inhibitors at beta adrenergic receptors and counter the effects of catecholamines such as epinephrine and nor-epinephrine.