Antagonistic indicator

L-Glutamate acts as an excitatory neurotransmitter at many synapses in the mammalian central nervous system. Electrophysiological measurements and the use of various selective agonists and antagonists indicate that different glutamate receptors co-exist on many neurons. 

Tamoxifen is an oestrogen-receptor antagonist indicated as adjuvant hormonal treatment in oestrogen-receptor-positive breast cancer in postmenopausal women. Common side-effects include alopecia and uterine fibroids. 

Ondansetron is a 5HT3 antagonist indicated as an anti-emetic agent in nausea and vomiting associated with chemotherapy. The dose administered depends on the emetogenic degree of the chemotherapeutic agents used. 

It is a cysteinyl leukotriene receptor antagonist indicated for the management of persistent asthma. It has been shown to have substantial blockade of airway leukotriene receptors 24 hours after oral dosing. Montelukast appears to be a useful alternative or adjunct to inhaled corticosteroid therapy in adults and an alternative to sodium cro-moglycate in children. 

Five subtypes of muscarinic receptors have been identified, primarily on the basis of data from ligand-binding and cDNA-cloning experiments (see Chapters 6 and 7). A standard terminology (M4 through M5) for these subtypes is now in common use, and evidence — based mostly on selective agonists and antagonists—indicates that functional differences exist between several of these subtypes. 

Foster KA, Regehr WG. Variance-mean analysis in the presence of a rapid antagonist indicates vesicle depletion underlies depression at the climbing fiber synapse. Neuron 2004 43 119-131. 

Figure II-4-13 Block of tachycardia due to Drug P by hexamethonium is indicative of a sympathetic reflex that follows a decrease in BP due to a vasodilator (choice B). Reversal of bradycardia due to Drug Q by hexamethonium indicates a vagal reflex elicited by vasoconstriction (e.g., alpha activation) masking cardiac stimulation (e.g., beta activation) typical of norepinephrine (choice C). Tachycardia due to Drug R is unaffected by any antagonist, indicative of a beta activator (choice D). Reversal of tachycardia due to Drug S by hexamethonium indicates a sympathetic reflex masking a vagotomimetic action typical of a muscarinic activator (choice A) this is confirmed by the effect of atropine.

Figure 5. Percentage of male CL reaching source (1 mg pheromone) 4-5 hours after injection of 0.1 pg/g OA plus the dose of antagonist indicated N 40 for each dose of antagonist. Solid line represents control response (16%).

Many studies have shown that chronic a,-adrenoceptor activation can induce cardiac hypertrophy. Studies in cells transfected with the recombinant a, adrenoceptors show that all three subtypes can increase levels of early gene markers of cellular proliferation (Garcia-Sainz et al., 1998). Use of subtype selective antagonists indicated that phenyel-phrine-induced hypertrophy in neonatal rat ventricular myocytes was mediated by the q , subtype (Knowlton et al.,... 

Hasse Diagram Technique and the concept of antagonistic indicators... 

By automated identification of antagonistic indicators with the WHASSE software, immanent conflicts in the evaluation matrix can be discovered in a convenient way, and thus the advantages and disadvantages of each option under discussion can be named. The precise knowledge about antagonisms supports the stakeholders decision process as further discussions can focus on these immanent evaluation conflicts. The methodologically strategy how to solve these conflicts is one of the most crucial steps of the evaluation process (Strassert 1995). 

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