In addition to its effects on the adrenergic system, there is evidence that indicates that propranolol may act as a weak antagonist of certain serotonin receptors, namely the 5-HT1A, 5-HT1B, and 5-HT2B receptors. The latter may be involved in the effectiveness of propranolol in the treatment of migraine at high doses.Both enantiomers of propranolol have a local anesthetic (topical) effect, which is normally mediated by blockade of voltage-gated sodium channels. Studies have demonstrated propranolols ability to block cardiac, neuronal, and skeletal voltage-gated sodium channels, accounting for its known membrane stabilizing effect and antiarrhythmic and other central nervous system effects. Mechanism of action
Propranolol is a non-selective beta receptor antagonist. This means that it does not have preference to Beta-1 or Beta-2 receptors. It competes with sympathomimetic neurotransmitters for binding to receptors, which inhibits sympathetic stimulation of the heart. Blockage of neurotransmitter binding to beta 1 receptors on cardiac myocytes inhibits activation of adenylate cyclase, which in turn inhibits cAMP synthesis leading to reduced PKA(Protein Kinase A) activation. This results in less calcium influx to cardiac myocytes through voltage gated L-type calcium channels meaning there is a decreased sympathetic effect on cardiac cells, resulting in antihypertensive effects including reduced heart rate and lower arterial blood pressure. Blockage of neurotransmitter binding to B2 receptors on smooth muscle cells will increase contraction, which will increase hypertension. Pharmacokinetics
Propranolol is rapidly and completely absorbed, with peak plasma levels achieved about 1–3 hours after ingestion. More than 90% of the drug is found bound to plasma protein in the blood.
Society and culture
In a 1987 study by the International Conference of Symphony and Opera Musicians, it was reported that 27% of interviewed members said they used beta blockers such as propranolol for musical performances. For about 10–16% of performers, their degree of stage fright is considered pathological. Propranolol is used by musicians, actors, and public speakers for its ability to treat anxiety symptoms activated by the sympathetic nervous system. It has also been used as a performance-enhancing drug in sports where high accuracy is required, including archery, shooting, golf, and snooker. In the 2008 Summer Olympics, 50-metre pistol silver medalist and 10-metre air pistol bronze medalist Kim Jong-su tested positive for propranolol and was stripped of his medals. Brand names
Propranolol was first marketed under the brand name Inderal, manufactured by ICI Pharmaceuticals (now AstraZeneca), in 1965. Propranolol is also marketed under brand names Avlocardyl, Deralin, Dociton, Inderalici, InnoPran XL, Indoblok, Sumial, Anaprilin, and Bedranol SR (Sandoz). In India it is marketed under brand names such as Ciplar and Ciplar LA by Cipla. Hemangeol, a 4.28 mg/mL solution of propranolol, is indicated for the treatment of proliferating infantile hemangioma. References
External links

Stapleton MP (1997). "Sir James Black and propranolol. The role of the basic sciences in the history of cardiovascular pharmacology". Texas Heart Institute Journal. 24 (4): 336–342. PMC 325477. PMID 9456487. "Propranolol". Drug Information Portal. U.S. National Library of Medicine.