EC50 values

The data are fit to curves with individual Emax, slope, and EC50 values. The parameters for these fit curves are given in Table 12.6b. 

Figure 3 Enhancement by brucine of ACh potency at Mi receptors in functional assays in membranes. Brucine (100 pM) increased the potency of ACh to stimulate [35S]GTPyS binding to G proteins in mi CHO cell membranes. In this experiment, the EC50 value for ACh decreased from 2.8 pM ( ) to 0.9 pM ( ) without significantly affecting the basal response or maximal stimulation. (From Ref. 9.)...

The prevalent receptor model for the excitatory amino acid is a tetrameric complex. As mentioned in the text, there is evidence that the channel conductance depends on the number of subunits that bind a ligand. Estimate the EC50 value and Hill coefficient for a dose-response curve assuming that the occupation at each subunit has a Kd value of 1 pi I, an % of 1, and that activation induces a transition to an active state independent of the state of the other subunits ... 

Dioxin-like activity was assessed by the AhR recombinant yeast assay (AhR-RYA) performed as described in Noguerol et al. [79]. BP1, with an EC50 value of 0.61 mg/L showed tenfold more dioxin-like activity than BP3, with an EC50 value of 6.8 mg/L. However, two of their metabolites, 4HB and DHMB, presented 4 and 11 times higher activities, with EC50 values of 0.16 and 0.59 mg/L, respectively. No dioxin-like activity was observed for either 4DHB or THB. 

A number of compounds activate TRPA1 without any apparent ability to form covalent adducts, including nonelectrophilic fenamate nonsteroidal anti-inflammatory drugs (NSAIDs), such as flufenamic acid (17, FFA), niflumic acid (18, NFA), and mefenamic acid (19, MFA) [13]. Phenols such as thymol (20) and 2-ferf-butyl-5-methylphenol (21) have been shown to activate human TRPA1 with micromolar EC50 values in stably transfected HEK293 cells [14]. 

A dimeric cyclam (biscyclam) 8 [ 12], with two cyclam moieties linked by a 3,6-dioxaoctane-l,8-diyl group at the C(6) positions, showed a remarkably improved anti-HIV activity after 4 days with the EC50 value... 

Table 1 Effective concentration (EC50) values of pesticides for bacteria, algae, crustaceans, and fish ...

As a typical example of a 6-heteroarylsubstituted dihydropyridazinone exhibiting antithrombotic activity motapizone, NAT 05-239 (63) (CAS 90697-57-7) may serve [96], Compound CCI 17810 (64) (CAS 76283-03-9) bearing a substituted phenyl moiety at C-6 of the pyridazine system has been shown to inhibit potently in vitro human platelet aggregation (induced by collagen, ADP, thrombin or arachidonic acid) with EC50 values in the range of 0.5-10/rg/ml [245], ... 

With respect to NP, the lowest EC50 values for microalgae were again observed for marine organisms. The EC50 for Thalassiosira pseudonana to NP is 27 p.g L-1 which is significantly lower than the EC50 values for... 

In a field study performed with nine surfactants from all groups except amphoteric [125], the laboratory effect concentrations were either lower than or similar to the mean in situ EC50 values for cationic and non-ionic surfactants. In contrast, for C12 and C13 LAS, the laboratory EC50 values were higher than the in situ effect concentrations. The short-term photosynthetic response to the same... 

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