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α1 Antagonist
Alpha-1 blockers (also called alpha-adrenergic blocking agents or alpha-1 antagonists) constitute a variety of drugs that block the effect of catecholamines on alpha-1-adrenergic receptors. They are mainly used to treat benign prostatic hyperplasia (BPH), hypertension and post-traumatic stress disorder. Alpha-1-adrenergic receptors are present in vascular smooth muscle, the central nervous system, and other tissues. When alpha blockers bind to these receptors in vascular smooth muscle, they cause vasodilation. Over the last 40 years, a variety of drugs have been developed from non-selective alpha-1 receptor antagonists to selective alpha-1 antagonists and alpha-1 receptor inverse agonists. The first drug that was used was a non-selective alpha blocker, named phenoxybenzamine and was used to treat BPH. Currently, several relatively selective alpha-1 antagonists are available. As of 2018, prazosin is the only alpha-1 blocker known to act as an inverse agonist at all alpha-1 adren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-1 Adrenergic Receptors
alpha-1 (α1) adrenergic are G protein-coupled receptors (GPCRs) associated with the Gq heterotrimeric G protein. α1-adrenergic receptors are subdivided into three highly homologous subtypes, i.e., α1A-, α1B-, and α1D-adrenergic receptor subtypes. There is no α1C receptor. At one time, there was a subtype known as α1C, but it was found to be identical to the previously discovered α1A receptor subtype. To avoid confusion, naming was continued with the letter D. Catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) signal through the α1-adrenergic receptors in the central and peripheral nervous systems. The crystal structure of the α1B-adrenergic receptor subtype has been determined in complex with the inverse agonist (+)-cyclazosin. Effects The α1-adrenergic receptor has several general functions in common with the α2-adrenergic receptor, but also has specific effects of its own. α1-receptors primarily mediate smooth muscle contraction, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
