Receptor antagonists/blockers

Clinically used p-adrenergic receptor antagonists ( P-blockers ) are either px-selective (e.g. bisoprolol, metoprolol, atenolol, betaxolol) or non-selective,... 

Opioids, benzodiazepines, barbiturates, corticosteroids, dopamine agonists (e.g., amantadine, bromocriptine, levodopa, pergolide, pramipexole, ropinirole), H2-receptor antagonists, anticholinergics (e.g., diphenhydramine, trihexylphenidyl), P-adrenergic blockers, clonidine, methyldopa, carbamazepine, phenytoin, baclofen, cyclobenzaprine, lithium, antidepressants (e.g., tricyclic antidepressants, selective serotonin reuptake inhibitors), and interleukin-2... 

A growing number of other diverse compounds have also been shown to bind to an allosteric site on the muscarinic receptors. Among them are pirenzepine (highly selective for Mi receptor), lidocaine and verapamil (ion channel blockers), tacrine (anticholinesterase compound), batrachotoxin, and strychnine (glycine receptor antagonist) [25,31-35],... 

The bioslurry treatment successfully removed several of the PhC to non-detectable levels after 26 days three histamine H2-receptor antagonists (ranitidine, famotidine, cimetidine), two (1-blockers (atenolol, sotalol), one barbiturate (butalbital) and one antidiabetic compound (glibenclamide). The elimination of the sulfonamide antibiotics sulfapyridine (100%), sulfamethazine (91.0%) and... 

The answer is d. (Hardman, pp 142—M3.) ACh will stimulate both muscarinic and nicotinic receptors. Skeletal muscle contraction is mediated through NM receptors, and ganglionic stimulation is an effect of NN receptors All of the other effects listed in the question occur following muscarinic receptor activation and will be blocked by atropine and scopolamine, both of which are muscarinic receptor antagonists. Skeletal muscle contraction will not be affected by these drugs rather, a neuromuscular blocker (e.g., tubocurarine) is required to antagonize this effect of ACh. 

Pronounced bradycardia with a beta blocker pronounced hypotension with an angiotensin II receptor antagonist... 

Competitive blocker of a-adrenergic receptors in heart and blood vessels Inhibits the enzyme HMG-CoA reductase and reduces the biosynthesis of cholesterol Acts as an angiotensin II receptor antagonist Inhibits the synthesis of prostaglandins via the selective inhibition of the enzyme cyclooxygenase-2... 

Sponge -Astrosclera willeyana Manzacidins A-D - a-ad renoreceptor blockers and serotonergic receptor antagonists 264, 265... 

Listing of antidepressants grouped by principal mechanism of action in the synapse. Abbreviations MAOI—irreversible = irreversible monoamine oxidase inhibitor MAOI—reversible = reversible monoamine oxidase inhibitor NDRl = norepinephrine/ dopamine reuptake inhibitor NRI = norepinephrine reuptake inhibitor NSRl = norepinephrine/serotonin reuptake inhibitor NSSA = norepinephrine/specific serotonin agonist SRI = serotonin reuptake inhibitor SRl/serotonin-2 blocker = serotonin reuptake inhibitor and serotonin-2 receptor antagonist. 

Fig. 5. Effect of WH on [Ca +], in Ang II-, CaCU or Bay K8644-stimulated VSMC. Ang II (10 UM)-induced [Ca " ]/ elevation (a) in Fura-2/AM-loaded VSMC was measured in the absence (Control) or presence of WH (300 juM). One pM PD 123177 as an AT2-receptor antagonist was added 10 min before Ang II addition. CaCf (2.5 mM) was added to VSMC treated with 2-APB (200 /xM IP3-R blocker)-containing Ca free PSS buffer (b). Effect of WH on [Ca ]/ in Bay K8644-stimulated VSMC was measured using a con-focal microscope and a fluorescent spectrometer (c). Bay K8644 (50 /xM)-induced [Ca ]/ elevation in VSMC was measured in the absence (Control) or presence of WH (300 /xM).

The ganglionic effects of ACh can be blocked by tetraethylammonium, hexa-methonium, and other substances (ganglionic blockers). None of these has intrinsic activity, that is, they fail to stimulate ganglia even at low concentration some of them (e.g hexamethonium) actually block the cholinoceptor-linked ion channel, but others (mecamyla-mine, trimethaphan) are typical receptor antagonists. 

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