Serial Agonist Addition
Serial Agonist Addition - Related Videos
08:06
Automated Acoustic Dispensing for the Serial Dilution of Peptide Agonists in Potency Determination Assays
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Cited by 1 •
2016
Peptide adsorption to plasticware during traditional tip-based serial dilutions can significantly impact potency determination and confound the understanding of structure-activity relationships used for lead identification and lead optimization phases of drug discovery. Here methods for automated acoustic non-contact serial dilution of peptide samples are described.
11:45
Quantifying Agonist Activity at G Protein-coupled Receptors
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Cited by 10 •
2011
A method for estimating the affinity constant of an agonist for the active state (Kb) of a G protein-coupled receptor is described. The analysis provides absolute or relative measures of Kb depending on whether constitutive receptor activation is measurable. Our method applies to various responses downstream from receptor activation.
01:27
Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)
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2025
α,β-Unsaturated carbonyl compounds with two electrophilic sites, the carbonyl carbon, and the β carbon, are susceptible to nucleophilic attack via two modes: conjugate or 1,4-addition and direct or 1,2-addition. Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon. Direct addition products are formed faster owing to...
01:03
Serial Position Effect
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2025
The serial position effect is a cognitive phenomenon where individuals are more likely to recall the first and last items in a list compared to those in the middle. This effect is divided into the primacy effect and the recency effect. The primacy effect is observed when the initial items in a list are remembered better. This occurs because these items are rehearsed more frequently or receive more elaborative processing, allowing them to be encoded into long-term memory more effectively. For...
10:53
Serial Dilutions and Plating: Microbial Enumeration
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2023
Source: Jonathan F. Blaize1, Elizabeth Suter1, and Christopher P. Corbo1 1 Department of Biological Sciences, Wagner College, 1 Campus Road, Staten Island NY, 10301 Quantitative assessment of prokaryotes can be onerous given their abundance, propensity for exponential proliferation, species diversity within a population, and specific physiological needs. Compounding this challenge, is the four-phase nature in which bacteria replicate (lag, log, stationary and death). The ability to accurately...
FAQs
Each agonist addition increases the concentration in the bath, and the preparation’s functional response is recorded across those progressively higher concentrations. Plotting these paired concentration and response observations produces a concentration–response relationship. This pattern shows how strongly the tissue or cells respond as exposure rises and provides the basis for assessing agonist activity under consistent experimental conditions.
The resulting relationship supports separate evaluation of potency and efficacy. Potency describes the concentration associated with a given level of response, whereas efficacy concerns the magnitude of the response the agonist can produce in the preparation. Considering both properties helps distinguish agonists that act at different effective concentrations from those that generate different maximum functional effects.
A response that changes with agonist concentration can provide evidence of pharmacological activity involving receptors, but interpretation becomes stronger when responses are examined with appropriate antagonist comparisons. Serial additions allow the agonist response to be measured in a controlled sequence, so changes associated with antagonist exposure can help evaluate receptor-mediated effects rather than relying on a single concentration.
After each sequential addition, the functional effect of the isolated tissue or cell preparation is recorded before the next concentration is introduced. Depending on the preparation, the measured outcome may be contraction, relaxation, or another functional response. Repeating this measurement across the concentration sequence supplies the observations needed to construct the concentration–response relationship.
Using one tissue or cell preparation for the concentration sequence reduces variation caused by differences between separate preparations. It also conserves experimental tissue because multiple concentrations can be assessed without replacing the sample after every dose. These features make comparisons within the experiment more consistent while preserving the preparation for additional pharmacological evaluation.
The technique is useful when investigators need to compare agonists, assess antagonist effects, or characterize responses in isolated tissues and cell preparations. It can accommodate contractile, relaxant, and other functional outcomes, allowing drug activity to be examined through a concentration–response relationship. The approach is therefore relevant to studies of potency, efficacy, and receptor-associated pharmacological responses.