What's the difference between agonism and antagonism?

Agonism


Definition:

  • (n.) Contention for a prize; a contest.

Example Sentences:

  • (1) The hypothesis that opiate agonism requires an N substituent in the axial position does not appear to be consistent with the increased potency of beta isomers in which axial N substituents are thermodynamically more unstable.
  • (2) Under conditions of 5-HT1-like, 5-HT2 and 5-HT3 receptor blockade, the following rank order of agonism was observed: 5-HT > 5-methoxytryptamine = renzapride > (S)-zacopride > (R,S-zacopride > 5-carboxamidotryptamine > BRL 24682 > (R-zacopride > metoclopramide > 2-methyl-5-HT > sulpiride.
  • (3) At the agonal stage, the isoproterenol dose-response curve was shifted significantly to the right in myocardial membranes from endotoxic rats, but there was no significant decrease in maximum stimulated activity.
  • (4) Agonal state effects the stability of brain compounds and causes brain hypoxia.
  • (5) However, further studies showed compounds which exhibited either partial agonism in the RFA and competitive antagonism of 5-HT in the RA, or antagonism of 5-HT in both arteries with different affinities.
  • (6) Catecholamines were detectable in the major neurons, in small intensely fluorescent cells, and in adrenergic fibers with varicosities at levels that varied with the patient's age, cause of death, duration of the agonal period, the treatment administered, and the time when the material had been taken after death.
  • (7) Certain derivatives of the antagonists naloxone and naltrexone showed partial agonism.
  • (8) Except for desGly(NH2)AVP, which is a weak V2 agonist, the remaining desGly and desGly(NH2) analogues of 1-3 exhibit substantial V2 agonism and are thus highly selective V2 agonists.
  • (9) But bureaucratic dysfunction means less than half have been given out – as shown by two state department charts – and only at the end of agonizingly long waiting periods .
  • (10) The results failed to support the female agonism hypothesis and indicate a need for more detailed studies of intermale social dynamics.
  • (11) In the inferior parietal cortex, agonal status confounded this comparison.
  • (12) Dilevalol is a novel antihypertensive agent combining vasodilation due to selective beta 2-adrenergic receptor agonism with nonspecific beta antagonism.
  • (13) The results indicate that alpha 2-adrenergic agonism with clonidine inhibits the bronchoconstriction induced by histamine.
  • (14) We have found no evidence of a physiologically relevant effect of serotonin agonism on osmoregulated vasopressin release, or on the ability of normal man to excrete a water load.
  • (15) The partial agonism of N alpha-guanylhistamine is related to the ability of the drug to bind with the receptor in two different modes with similar affinity.
  • (16) In contrast U50,488H produced biphasic curves characterized by a higher potency phase of agonism that was susceptible to antagonism by 16-methylcyprenorphine (RX8008M) and a lower potency phase that was apparently non-opioid in nature.
  • (17) As this profile of activity is not shared by the shorter-acting compound, salbutamol, it would seem that anti-inflammatory activity is associated with beta-adrenoceptor agonism of long duration.
  • (18) To clarify the regulation of duodenal motility, the aim of the present study was to investigate the effects of alpha-adrenoceptor agonism and blockade and of galanin on duodenal motility.
  • (19) Agonist-independent pA2 estimates for ICS 205-930 (6.3-6.6) suggest a single site of agonism.
  • (20) In addition, analyses of beta-adrenoceptor agonism and antagonism, using selective (beta 1: T-1583, beta 2: procaterol) and non-selective (isoproterenol) agonists as well as selective (beta 1: atenolol, beta 2: ICI 118,551) and non-selective (propranolol) antagonists, confirmed that beta-adrenoceptors in the canine facial vein are not homogeneous, with the beta 1-subtype predominating over the beta 2-subtype, and that the canine saphenous vein has a homogeneous population of the beta 2-subtype, as reported in the other species.

Antagonism


Definition:

  • (n.) Opposition of action; counteraction or contrariety of things or principles.

Example Sentences:

  • (1) Intrathecal injection of zopiclone potentiated morphine antinociception, while the intracerebroventricular injection of zopiclone failed to enhance morphine antinociception and the intracerebroventricular injection of flumazepil to antagonize the intraperitoneal-zopiclone-induced increase in morphine antinociception.
  • (2) of PLA2 caused marked degranulation of mast cells in the rat mesentery which was facilitated by addition of calcium ion (10 mM) but antagonized by pretreating with three antiinflammatory agents.
  • (3) [Ca2+]i exhibited a sigmoidal dependence on [Na+]o. Mg2+, a competitive inhibitor of Na2+-Ca2+ antiport in these cells, antagonized the increase in [Ca2+]i produced by lowering [Na+]o.
  • (4) Increases in extracellular calcium antagonized the negative inotropic effect.
  • (5) In K+-depolarized basilar arteries, ifenprodil competitively antagonized the response to Ca2+, and this was enhanced by pre-incubation in calcium hopantenate.
  • (6) During the postovulatory phase, endogenous progesterone and the production of metabolites antagonized this effect.
  • (7) An antagonism is unlikely when ciprofloxacin is combined with one of the beta-lactams studied or with tobramycin.
  • (8) Co-application of CGS 9896, a benzodiazepine receptor antagonist, did not antagonize the guanidino compound-induced inhibition of GABA responses.
  • (9) Aortic rings from the rabbit were similarly potently antagonized by the protein kinase C inhibitors, however, K(+)-induced contractions were also equally sensitive to these agents in both rat and rabbit tissues.
  • (10) The biphasic response to (-)-(S)-Bay K 8644 and (+)-(S)-202-791 suggests that the properties of Ca++ channel activation and antagonism may reside within a single 1,4-dihydropyridine molecule.
  • (11) We have investigated the bacterial antagonism exerted in oral secretion by alpha-hemolytic streptococci against S. aureus and S. epidermidis.
  • (12) The marine natural product lophotoxin has produced a non-reversible antagonism of parasympathetic and sympathetic functions that are known to be mediated by C6 sub-type nicotinic receptors.
  • (13) Strains showing occasional antagonism at a particular proportion of concentrations of the test combination, were found to only be indifferent when the mean index of the fractional inhibition concentration of all checkerboard combinations was calculated.
  • (14) The omission of glucose induced a marked increase in the efflux of [3H]GABA, which was antagonized by TTX (1 microM), but not by MK 801 (1 microM) or DNQX (100 microM).
  • (15) The hyperthermia in rabbits caused by the serotonergic stimulants cited above is also antagonized by pretreatment with MS.
  • (16) The neuroleptic agents haloperidol, fluphenazine, domperidone, sulpiride and tiapride also antagonized emesis induced by cisplatin but only a proportion of the animals were completely protected and diazepam and prednisolone only reduced the intensity of the response.
  • (17) These results suggest that formoterol modifies allergen-induced airway responses through functional antagonism rather than the inhibition of inflammatory cell infiltration.
  • (18) Depolarizations induced by acetyl-Arg6-septide, a NK1-receptor selective agonist, were also antagonized by spantide with a pA2 of 6.5.
  • (19) 5-Hydroxytryptamine contracted the musculature from all parts of the respiratory tract-an effect which was specifically antagonized by both methysergide and atropine.4.
  • (20) K showed little activity against LTC4 but could antagonize more selectively H- and ACh-mediated effects.

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