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Receptors Any drug or compound with specific effects has a receptor. You can read about this general concept in Goodman and Gillman's The Pharmacological Basis of Therapeutics. Chapter 1 introduces the concept, chapters 3 and 5 expand further. As far as the history of this concept is concerned, receptors mediating the specificity of action was first clearly ...


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Specific parts — moieties — of an agonist molecule bind to the receptor protein, causing the receptor to change shape, which in turn initiates a signaling pathway inside the cell. Some agonists are better at causing the receptor to change to its "optimal shape" for relaying signal. These are called "full agonists". Other agonists cause a partial change in ...


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Fluorine has a combination of unique chemical properties, which makes it very useful in drug design : It is small, such that replacing a C-H with a C-F is often possible, from a sterical point of view. Halogens, which share some of the other desirable properties of fluorine, are much larger. It is very electronegative: it will attract electrons strongly, ...


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In addition to De Novo's excellent answer, I would like to add that sometimes, the fact that we have receptors for something is precisely a sign that we should not consume that thing. When it comes to taste and smell in particular, many receptors are evolutionarily conserved precisely because their physiological role is to warn us of a danger. For example, ...


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The reason is to make it easier to determine a suitable dose from the graph. Normally, using a arithmetic scale, the response curve is a hyperbolic, with most of the information squished together in a small section of the graph. By using the log the function usually becomes somewhat sigmoid, with a relatively linear section in the transition from low-high ...


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The process of downregulating a receptor by internalizing and degrading it in response to (sometimes prolonged) activation or (sometimes prolonged) failure to activate is what pharmacologists call desensitization (in either context). You can read about this generally in Goodman and Gilman's Pharmacological Basis of Therapeutics, Chapter 3, under the ...


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Resistance to antiviral therapy is a problem in the treatment of many viral illnesses. Influenza is particularly significant given the epidemiological characteristics of the disease. This Nature Medicine article gives a good overview of oseltamivir resistant pandemic H1N1, which is a useful example, since our assumption that resistant virus would not ...


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It's not that people didn't want to use hemagglutinin as a target for antivirals, it's that they haven't been able to get the antivirals through the approval process yet. There are a number of experimental inhibitors (see for example Progress of small molecular inhibitors in the development of anti-influenza virus agents) but the approval and licensing ...


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Short answer Atropine inhibits an inhibitor and hence its effects are excitatory. Background According to the wiki page on muscarine M2 receptor: M2 muscarinic receptors act via a Gi type receptor, which causes a decrease in cAMP in the cell, generally leading to inhibitory-type effects. Atropine is an antimuscarinic (anticholinergic) drug....


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activity "addition of a methyl group to the phenyl ring changed its activity from agonist to antagonist"


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According to a review (Prausnitz2004), marketed drugs with a dermal route of administration tend to fulfil the following criteria : Small molecular size (< 500 Da) High lipophilicity Small required dose (up to ~milligram) This is a consequence of the structure of the skin (with a lipophilic stratum corneum, and low diffusion speed) and practical ...


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Yes. The antibiotic (general microorganism “targeter”) you’re looking for is an antifungal. There are fewer ways to target fungi as opposed to bacteria, but we can target them nonetheless. The fungal cell membrane has ergosterol to regulate its permeability whereas the mammalian cell relies on cholesterol. Fungi have cell walls which are not present in ...


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There are a few important things to consider as you interpret these data. Here potency means Chlorpromazine equivalents When your linked review refers to potency, it is likely referring to the old concept of chlorpromazine equivalents. The table in the article cites Jibson and Tandon in a review in CNS news special report from 2001. This is not a standard ...


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Unless your polymorphisms have been tested against a particular drug, you can't extrapolate a starting dosage for it based only on your genotype. It's better to actually take the drug, and change dosage based on observations. See this paper https://www.ncbi.nlm.nih.gov/pubmed/24935087 CONCLUSIONS AND RELEVANCE: In this meta-analysis of randomized ...


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No. Irreversible antagonism is, by definition, inhibition that cannot be reversed by the agonist. Let me summarize the basics. You can read about this in Goodman and Gillman's The Pharmacological Basis of Therapeutics, Chapter 3, but there are many basic biochemistry textbooks that will cover the same ground. When an interaction between a ligand and a ...


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Partial Answer and Suggestions As @De_Novo says, this is a complicated, albeit very interesting, question. There are various reasons for this, such as the fact that the receptors aren't just internalised but also recycled and the fact that there may be antagonist and dose-dependent changes in receptor internalisation. There's the added complexity that ...


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tl;dr Hypokalemia hyperpolarizes membranes by increasing the $K^+$ gradient, making $\mathcal{E}_K$ and consequently $\mathcal{E}_m$ more negative. This makes any signaling event controlled by depolarization less responsive. It's complicated, but we can understand the effect by looking at $K^+$ alone Good catch. Yes, the video (and diagram) are incorrect....


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Your source (DrugBank via PubChem) is describing the typical pharmacokinetic information (ADME, absorption, distribution, metabolism, excretion) on Providine-Iodine, under the assumption it is not absorbed. It's true, a thing that is not absorbed has no volume of distribution, is not metabolized, and is not eliminated. Though Providine-Iodine is not ...


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Does body fat percentage effect storage of fat soluble compounds? Generally, yes. Phenytoin, an anti-seizure drug, provides a good and well studied example. The key issue here is that, for phenytoin, plasma half-life is proportional to the apparent volume of distribution of the drug. (Apparent) volume of distribution is a pharmacokinetic property of a ...


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The short answer is that an inverse agonist binds preferentially to the inactive state of the receptor, so it reduces the receptor's intrinsic, basal activity. The agonist was only raising the activity, not switching it on. The most basic model of receptor pharmacology is that the receptor, $\ce{R}$, and the agonist, $\ce{A}$, are in a chemical equilibrium: ...


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Short Answer You might be interested in learning about telomeres, telomerase, and telomerase gene therapy. For example, Boccardi & Herbig (2012): describe a mouse study in which they used telomerase gene therapy to improve the healthspan and lifespan of mice by up to 24%. As far as I know, we have no successful human trials of similar therapies that ...


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Reverse use dependence is the reduction of a drug's efficacy with the repeated use of the target. This contrasts with ordinary use dependence, for instance with $\mathrm{Na}^+$ blocking local anaesthetics, where they exert more block after tissue use. Reverse use dependence is particularly (but not exclusively) seen with channel blockers such as quinidine. ...


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When a tumor is removed from a patient, it is usually send to the pathology the make sure that it has been excised completely to make sure there are no residues. Often this tumor is also used to analyze the mutation status of the tumor to determine, which further treatment is possible. For example, this is routinely done for melanoma where the mutation ...


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Not within the next two decades, at least (assuming you meant nearly total reversal of the effects of physiological aging). Any further than that is impossible to predict, since we are likely only a few breakthroughs away at this point (however, with extremely bad luck, these could take centuries to achieve, since presumably no scientist knows the 'optimal ...


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What are CYPs? How are they different from other enzymes? Cytochrome P450 enzymes (CYPs) are a large family of enzymes involved in the metabolism of many endogenous and exogenous compounds (including typical dietary substances and pharmaceuticals). There are many different CYPs, each individual CYP form can metabolize many different compounds, and a single ...


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I think the OP is asking the following: If an enzyme is not specific one substrate, but is simultaneously presented with a pair of substrates, which one 'wins' and how do we decide? For example, if an enzyme is presented with a racemate such that the D-form has a 10-fold lower $K_m$ than the L-form, but the L-form has a 5-fold higher $k_{cat}$, which ...


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I am not an expert on HIV but I am answering based on general principles. This is a typical example of selection of individuals/populations with different fitness. Reversion to wild-type (WT) would happen if the WT has higher fitness in that environment. Assuming that WT is the fittest under drug-free conditions, it is not difficult to understand that the ...


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Good question, but first I'll address a note in the comments. In bronchial smooth muscle, do β2 receptors receive sympathetic innervation? Canning and Fischer (2001) claim that bronchial smooth muscle do receive sympathetic innervation. But it would still be correct to say that β2 expression plays little role in regulating smooth muscle tone in the human ...


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A technical word that encompasses agonists, antagonists etc. is effector, defined in the Wikipedia entry as follows: Effector In biochemistry, an effector molecule is usually a small molecule that selectively binds to a protein and regulates its biological activity. However ‘effector’ does tend to be used more in regulation of enzyme activity than ...


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All things being equal, does that mean an administration of a drug will be twice as potent if the bioavailability is doubled? Bioavailability is initially taught, and sometimes reported as a proportion, $F$, the concentration in drug in plasma under a test condition (typically oral administration) over the concentration of of the same dose of the drug under ...


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