Table 2. Examples of important receptors, their agonists and antagonists Receptor type Subtype Site(s) in the body Agonists Antagonists Adrenoceptors α/β Adrenaline Labetalol Noradrenaline α1/α2 Phentolamine Phenoxybenzamine α1 Pupillary dilator Dopamine (high doses) Doxazosin muscle Phenylephrine Indoramin Vascular smooth Prazosin muscle α2 CNS Clonidine Yohimbine Presynaptic nerve terminals β1/β2 Dopamine Propranolol Isoprenaline Oxprenolol β1 CNS Dobutamine Atenolol Heart Dopamine (moderate Metoprolol doses) Propranolol β2 Pancreatic islets Fenoterol Smooth muscle Rimiterol (bronchiolar, Salbutamol vascular, uterine) Terbutaline Angiotensin AT1 Cardiovascular Angiotensin Eprosartan Irbesartan Losartan Valsartan Cholinoceptors Muscarinic Tissues innervated Acetylcholine and Atropine and analogues by parasympathetic analogues (e.g. Disopyramide nerves carbachol, bethanecol) Orphenadrine Pirenzepine (M1 selective) Quinidine Tricyclic antidepressants Trihexyphenidyl Nicotinic Neuromuscular Acetylcholine and Aminoglycoside junction some analogues (e.g. antibiotics Postganglionic cells carbachol) Ganglion-blocking drugs in ganglia Neuromuscular-blocking drugs Quinidine Dopamine Various CNS Apomorphine Butyrophenones (e.g. receptors Renal vasculature Bromocriptine haloperidol) Dopamine (low doses Domperidone (D2) Metoclopramide Phenothiazines (e.g. chlorpromazine) Thioxanthenes (e.g. flupentixol) GABA GABAA- CNS GABA Bicuculine receptors BDZ Benzodiazepines complex GABAB CNS (presynaptic) GABA Baclofen
Table 2. Examples of important receptors, their agonists and antagonists Receptor type Subtype Site(s) in the body Agonists Antagonists Adrenoceptors α/β Adrenaline Noradrenaline Labetalol α1/α2 Phentolamine Phenoxybenzamine α1 Pupillary dilator muscle Vascular smooth muscle Dopamine (high doses) Phenylephrine Doxazosin Indoramin Prazosin α2 CNS Presynaptic nerve terminals Clonidine Yohimbine β1/β2 Dopamine Isoprenaline Propranolol Oxprenolol β1 CNS Heart Dobutamine Dopamine (moderate doses) Atenolol Metoprolol Propranolol β2 Pancreatic islets Smooth muscle (bronchiolar, vascular, uterine) Fenoterol Rimiterol Salbutamol Terbutaline Angiotensin AT1 Cardiovascular Angiotensin Eprosartan Irbesartan Losartan Valsartan Cholinoceptors Muscarinic Tissues innervated by parasympathetic nerves Acetylcholine and analogues (e.g. carbachol, bethanecol) Atropine and analogues Disopyramide Orphenadrine Pirenzepine (M1 selective) Quinidine Tricyclic antidepressants Trihexyphenidyl Nicotinic Neuromuscular junction Postganglionic cells in ganglia Acetylcholine and some analogues (e.g. carbachol) Aminoglycoside antibiotics Ganglion-blocking drugs Neuromuscular-blocking drugs Quinidine Dopamine receptors Various CNS Renal vasculature Apomorphine Bromocriptine Dopamine (low doses Butyrophenones (e.g. haloperidol) Domperidone (D2) Metoclopramide Phenothiazines (e.g. chlorpromazine) Thioxanthenes (e.g. flupentixol) GABA receptors GABAA- BDZ complex CNS GABA Benzodiazepines Bicuculine GABAB CNS (presynaptic) GABA Baclofen
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