
	Where results make sense

Topic: Competitive antagonist

Related Topics

Receptor antagonist

Antagonist

Opioid

Antipyretic

Prostate gland

Acetaminophen

Morphine

Aspirin

In the News (Fri 11 Dec 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Receptor antagonist - Wikipedia, the free encyclopedia
		In medicine and biology, a receptor antagonist is a ligand that inhibits the function of an agonist and inverse agonist for a specific receptor.
		Unlike competitive antagonism, the covalent nature of the bond means the antagonist cannot be displaced by raising the concentration of the agonist.
		The antagonist which is bound is usually the one with the higher affinity for the receptor.
	en.wikipedia.org /wiki/Receptor_antagonist (417 words)

	Receptor Workbook
		An antagonist which binds to the receptor in a reversible manner is referred to as a competitive antagonist.
		Therefore, the major effect of a competitive antagonist is to shift the dose-response curve for an agonist to the right.
		Prazosin is a competitive antagonist at the same receptor phenylephrine acts.
	www.mc.uky.edu /pharmacology/instruction/pha621mp/pha621mp.html (3901 words)

	Receptor Workbook
		An antagonist that binds to the receptor in a reversible mass-action manner is referred to as a competitive antagonist.
		However, because higher agonist concentrations were necessary to displace the antagonist, the agonist dose-response curve is shifted to the right in the presence of a competitive antagonist.
		The dose-response curve obtained in the presence of a competitive antagonist is parallel to the dose-response curve obtained in the absence of antagonist.
	www.mc.uky.edu /pharmacology/instruction/pha824mp/PHA824mp.html (4044 words)

	Primary FRCA Course-Online Lectures, Leicester, UK
		Therefore, antagonists 1 and 2 are competitive and antagonist 3 is irreversible or non competitive.
		Competitive (reversible) antagonism: The antagonist binds reversibly to the same region of the receptor to which the agonist binds.
		The antagonist effect cannot be overcome by increasing the concentration of the agonist as the binding to the receptor is irreversible.
	www.le.ac.uk /anaesthesia/primfrca/aodanswers.html (262 words)

	The Ibogaine Dossier
		Although NMDA receptor antagonists of the phencyclidine (PCP) type are precluded from clinical use because of their psychotomimetic properties, amantadine and memantine have been administered to human patients with idiopathic Parkinson's disease and spasticity for many years without serious adverse effects.
		Although noncompetitive antagonists increase motility in rodents, whereas competitive antagonists do not, both classes of compounds appear to induce schizophrenia-like psychosis in human beings, and cause similar changes in a variety of different biogenic amine neurotransmitter systems in the limbic and motoric areas of the brain.
		Competitive antagonism of glycine at the N-methyl-D-aspartate (NMDA) receptor.
	www.ibogaine.org /lit-nmda.html (7184 words)

	Lycaeum > Leda > NMDA Antagonist Neurotoxicity: Mechanism and Prevention
		Antagonist of the NMDA sub type of glutamate receptor are potentially useful for preventing neuronal degeneration in neurological disorders such as stroke (1).
		The proposal that the pathomorphological and psychotomimetic side effects of NMDA antagonists may be causally linked rests on the reasonable assumption that reversible injury confined to cingulate retrosplenial neurons might produce a temporary derangement in psychological functions mediated by any or all components of an extensive neural network with which these neurons communicate.
		Behavioral side effects of competitive and noncompetitive NMDA antagonists are similar and consist of ataxia and hyperactivity at low to moderate doses, with a progressive increase in muscle tone at higher doses that causes the animals to lie on their sides with partially flexed limbs held in a rigid posture.
	leda.lycaeum.org /?ID=13066 (1897 words)

	http://www.bio-balance.com/
		Although it appears surprising that the combination of an agonist with a competitive antagonist in a specific ratio can maintain the receptor in an active conformational state, this theoretical model predicts these results and supports the concept that desensitization can be controlled primarily at the level of the initial receptor response.
		Combining an antagonist with an agonist in a specific ratio, prevents the binding of the agonist with the inactive receptor state and thereby prevents the desensitization of the receptor.
		The specific ratio of antagonist to agonist can be calculated so that the competition with the active receptor state is minimized relative to the competition with the inactive, or lower affinity state, thereby maintaining the essential agonist interaction with the active receptor state (17).
	www.bio-balance.com /Lanzara_Pharm1.htm (7709 words)

	[No title]
		NPS-1506 is a non-competitive NMDA receptor antagonist with a moderate affinity to its receptor.
		Dextromethorphan and its analogue AHN649 are relatively selective, low-affinity NMDA antagonists, and have been shown to have neuroprotective efficacy in a rat model utilizing temporal intraluminal filament occlusion of the middle cerebral artery.
		Aptiganel (CNS 1102) is a selective, non-competitive antagonist that acts on the ion channel associated with the NMDA receptor and has been shown to be neuroprotective in neonatal lambs after HCA.
	www.pitt.edu /~Super1/lecture/lec9191/011.htm (865 words)

	pharmacology concepts: receptors
		Since there are 4 times as many antagonist molecules as agonist molecules, it s more likely that antagonists will bind to the receptors.
		Since the number of receptors activated determines the size of an agonist response, the response to an agonist is reduced in the presence of antagonist.
		This is different from competitive antagonists which reduce drug potency without affecting efficacy.
	abdellab.sunderland.ac.uk /lectures/Brain/receptors/receptors2.html (233 words)

	Memantine, L5
		As an NMDA antagonist, memantine prevents the neurotransmitter glutamate from leading to nerve cell degeneration by inhibiting glutamate´s binding to the receptor.
		As an antagonist, memantine prevents the excessive binding of glutamate to NMDA receptors, inhibiting the pathway to excessive NMDA activation and nerve cell death.
		Memantine differs from other NMDA non-competitive antagonists in that it allows the NMDA receptor to undergo physiological activity required for normal nerve cell functioning, while at the same time preventing the receptor from the over-activation that leads to nerve cell death.
	www.stanford.edu /group/hopes/treatmts/antiglut/l5.html (1766 words)

	Neuropharmacology (Site not responding. Last check: 2007-10-09)
		B. Agonist activation of a response in the presence of increasing concentrations of a competitive antagonist yields a series of parallel rightward shifted dose-response curves.
		The dose ratio is the ratio of the agonist concentration (or doses) required to elicit equal responses in the presence and absence of antagonist.
		for a competitive antagonist for receptor occupancy and hence blockade of response.
	www.utdallas.edu /~tres/pharm/binding/display2_07.html (131 words)

	Doseresponse curves in the presence of antagonists (Site not responding. Last check: 2007-10-09)
		Investigations of antagonists that are not surmountable or reversible are beyond the scope of this manual.
		A competitive antagonist binds reversibly to the same receptor as the agonist.
		Gaddum derived the equation that describes receptor occupancy by agonist in the presence of a competitive antagonist.
	dwb.unl.edu /Teacher/NSF/C03/C03Links/www.curvefit.com/schild.htm (1559 words)

	Agonists and Antagonists - The Merck Veterinary Manual
		A competitive antagonist results in reversible inhibition that can be overcome by increasing the concentration of agonist.
		However, at low concentrations, a noncompetitive antagonist may cause a parallel shift of the log dose-effect curve to the right without reducing the maximal response of the agonist.
		Conversely, antagonists have a higher affinity for the receptor’s inactive conformation and push the equilibrium to the inactive state, producing no effect.
	www.merckvetmanual.com /mvm/htm/bc/190113.htm (444 words)

	The Kinetics of Competitive Antagonism by Cisatracurium of Embryonic and Adult Nicotinic Acetylcholine Receptors -- ...
		Competitive antagonists to nicotinic acetylcholine receptors are clinically used as muscle relaxants.
		Competitive antagonists to nAChR are clinically used to immobilize patients during surgery.
		Colquhoun D and Sheridan RE (1982) The effect of tubocurarine competition on the kinetics of agonist action on the nicotinic receptor.
	molpharm.aspetjournals.org /cgi/content/full/60/4/797 (6414 words)

	Enhancement of Glutamate Release by L-Fucose Changes Effects of Glutamate Receptor Antagonists on Long-Term ...
		by antagonists of the metabotropic glutamate receptors (e.g.,
		of the antagonist for metabotropic glutamate receptors, MCPG, on LTP in the hippocampal CA1 region.
		Phenylglycine derivatives as antagonists of metabotropic glutamate receptors.
	www.learnmem.org /cgi/content/full/7/4/227 (3269 words)

	Strychnine: A Potent Competitive Antagonist of alpha -Bungarotoxin-Sensitive Nicotinic Acetylcholine Receptors In Rat ...
		Strychnine: A Potent Competitive Antagonist of alpha -Bungarotoxin-Sensitive Nicotinic Acetylcholine Receptors In Rat Hippocampal Neurons -- Matsubayashi et al.
		1) is a well-known competitive antagonist of glycine at glycine-gated Cl channels (Saitoh et al.
		a rapid dissociation of the antagonist from the receptor and a
	jpet.aspetjournals.org /cgi/content/full/284/3/904 (6447 words)

	Use of ibogaine in reducing excitotoxic brain damage - Patent 5629307
		Non-NMDA antagonists that penetrate blood CNS barriers have not been available for a long enough time to allow them to be tested for neuroprotective efficacy against all types of neuropathological conditions involving excessive Glu activity.
		Therefore, it is now recognized that various competitive NMDA antagonists and various non-competitive NMDA antagonists all cause the same pathomorphological effects in rat brain (Olney et al 1991; Hargreaves et al 1993) and also have psychotomimetic effects in humans (Kristensen et al 1992; Herrling 1994; Grotta 1994).
		It is considered likely that NMDA antagonists will prove useful in the therapeutic management of such chronic diseases, and ibogaine, as an NMDA antagonist that does not cause toxic side effects, is also a good candidate drug for preventing and reducing such gradual neurodegeneration.
	www.freepatentsonline.com /5629307.html (9096 words)

	Problem Set 2 Comments
		D-tubocurarine is a reversible competitive antagonist of acetylcholine at the neuromuscular junction.
		A reversible competitive antagonist acts by competing with the agonist for receptor binding.
		Therefore it is possible to overcome a competitive blockade by increasing the concentration of agonist.
	www.bumc.bu.edu /www/busm/pharmacology/programmed/Lab2.html (3016 words)

	Pharmacology I Intro #1 of 2
		Reversible binding: Competitive antagonists are usually weak bonds with low to medium affinity, come on and off with mass action.
		Receptor supersensitivity occurs after exposure of receptor to antagonist, inhibition of synthesis, or release of cognate neurotransmitter or hormone.
		Agonist and competitive antagonist: Both compete for the same receptor site so the curve will shift to the right and be less potent.
	members.tripod.com /mna2001/pharmacology/pharm1/pharm1.intro1of2.htm (2604 words)

	Microscopic Kinetics and Energetics Distinguish GABAA Receptor Agonists from Antagonists -- Jones et al. 81 (5): 2660 ...
		In contrast, the slow component of the rising phase increased in relative amplitude with antagonist concentration.
		The equilibrium occupancy by antagonist in the absence of GABA was obtained by plotting the y-intercepts from Fig.
		The line describing antagonist binding rates is significantly different from that for agonist binding but not significantly different from a line with zero slope (see Methods).
	www.biophysj.org /cgi/content/full/81/5/2660 (5893 words)

	Site-specific fluorescence reveals distinct structural changes with GABA receptor activation and antagonism - Nature ...
		We also show that competitive antagonists induced distinct rearrangements on their own that stabilized the receptor in a closed state.
		It is generally accepted that competitive antagonists block receptor activation by binding within the agonist-binding pocket and preventing access of the agonist molecule.
		These data confirm that antagonists, on their own, can induce structural changes and, furthermore, that these structural changes are distinct from those induced by agonists.
	www.nature.com /uidfinder/10.1038/nn926 (4519 words)

	Analysis of the Effects of Candesartan in the Mesenteric Vascular Bed of the Cat -- Champion and Kadowitz 30 (5): 1260 ...
		is a competitive antagonist at the AT receptor.
		that candesartan is a noncompetitive AT receptor antagonist.
		II induced by candesartan are dependent on the dose of the AT receptor antagonist studied.
	hyper.ahajournals.org /cgi/content/full/30/5/1260 (4770 words)

	The Bioline EPrints Archive - Purification of a functional competitive antagonist for calcitonin gene related peptide ... (Site not responding. Last check: 2007-10-09)
		The purified molecules induced an inhibition of the CGRP stimulated adenylate cyclase activity, this effect was specific as no such effect was observed on the glucagon stimulated adenylate cyclase activity measured in the same rat liver membrane preparation.
		These results suggest that the purified molecules may act as antagonists for peptides that bind to CGRP receptors in rat liver membranes.
		These new antagonists may be of particular importance in various aspects of CGRP action in vertebrates.
	bioline.utsc.utoronto.ca /archive/00000259 (238 words)

	- Avanti Polar Lipids
		VPC 32179 is devoid of agonist activity at the human LPA2 and LPA3 receptors and behaves as a competitive antagonist at the LPA3 receptor.
		The lead compound in the series, VPC23019, was found in broken cell and whole cell assays to behave as a competitive antagonist at the S1P{sub}1 and S1P{sub}3 receptors.
		Additionally, the implications of installing nonhydrolyzable phosphate head group isosteres with regard to antagonist potency and selectivity at LPA receptors is described.
	www.avantilipids.com /vpc.asp (865 words)

	Molecular Pain \| Full text \| Acidification of rat TRPV1 alters the kinetics of capsaicin responses
		These results highlight the breadth of TRPV1 responses to different stimuli and the concept that this channel (as well as other TRP channels) may act not only as an integrator of different physical stimuli but also as a coincidence detector that may be important in determining the resultant physiological response to endogenous activators.
		These results are consistent with competitive mechanism of action for this antagonist (Table 3).
		It is possible that binding of the antagonist to the channel results in a conformational change that inhibits channel function independent of the mode of activation.
	www.molecularpain.com /content/1/1/28 (5092 words)

Try your search on: Qwika (all wikis)