A receptor is a molecular target for a chemical signal such as a neurotransmitter, hormone, or drug. Binding of the signal to the receptor initiates or modulates behaviour in the receiving cell.

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Density of Receptors of a mammal

I know it's a very open question. It's for a paper. So as a reference I'm looking maybe for the average density of insulin receptors per cell of a human tissue. I want to compare it to the density of ...
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Is tolerance unavoidable?

Do all psychoactive substances induce tolerance eventually? For that matter, do all receptor-binding substances induce tolerance eventually? It seems certain that different substances take different ...
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Why do Hot/Cold drinks taste sweeter once returning to room temperature?

Now, I know this is a very bizarre question, and I tried to find a correct exchange for this, but it might relate to biology/science as it being our taste buds and everything. I am so sorry if there ...
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Do antagonist-receptor complexes get absorbed into the cell?

My understanding is that normally, a neurotransmitter binds to a receptor and then that ligand-receptor complex gets absorbed into the cell and either degraded or recycled. So does the same thing ...
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RAGE Oligomerization and Signalling Mechanism

I am looking to understand the mechanism of how the advanced glycation end products, s100 proteins and B-amyloids interact through oligomerization with the RAGE molecule (AGE receptor). I would also ...
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Is receptor antagonism just long-term binding?

By my understanding, a substance that binds to a receptor and activates it is called an agonist, while a substance that binds to a receptor without activating it is called an antagonist. (Wiki) What ...
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The mechanism of mechanoreception?

I am interested in knowing the molecular mechanism behind mechanoreception/mechanotransduction (i.e. mechanism behind receptor potential generation on mechanical stimulation). I know that most ...
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Which of the three is true for insulin receptors?

I have seen the following question in a Cell Biology exam: Which of the following is true" Insulin has an hydrophobic Signal Peptide and the insulin receptor does not have an hydrophobic ...
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What are the effects of removing CD4 receptors?

If the gene for the CD4 receptor was removed, would the person's immune system work normally? Could a new artificial receptor be substituted in place of CD4? Could HIV infection be prevented in this ...
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Can you knockout specific receptors in an adult?

Sorry I don't have a good understanding of this topic, but I'm guessing that "receptor knockout" is related to/a part of "gene knockout"? And If I understand correctly, gene knockout is currently ...
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91 views

Why do we get sleeply after we eat?

After we have eaten, we feel cold and sleepy. I think it's because the maximum blood supply is transferred towards the digestive system so that digestion is done, and therefore the brain to does not ...
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Toll Like Receptors Vs Toll Receptors

What are the major differences between them, apart from one being in humans and other in Drosophilla?
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How is adrenaline a ligand?

I keep reading that adrenaline is a ligand, however from what I understand a ligand is a molecule or ion which donates a pair of electrons to a central transition metal ion in a complex. How then is ...
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What is the essence of difference of how different chemicals affect the same receptor?

It is known that various chemicals can bind to the same receptor type, producing different effects. Be these chemicals agonists or antagonists, there are more variations in how they influence the ...
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Neuroscience behind the crash

After experiencing things like stress, intense exercise, or using drugs such as caffeine and amphetamine, subjects often assume a depressive and lethargic state afterwards, known as a "crash." What is ...
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What is the lifetime of the vasopressin receptor V2?

I was looking at the production of vasopressin receptor 2, also known as V2R or ADH-R. What I found is that it is coded by the AVPR2 gene and degraded by the Alix protein (source). But I did not get ...
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Isotretinoin and retinoid receptors in brain confusion?

I am considering starting a treatment with Accutane(Isotretinoin), however I am not sure about what the effects on the brain are. Here are two studies that contradict each other: http://www.ncbi.nlm....
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Does suffocation pain involve nociceptors?

I never suffocated myself so not entirely sure, but when you suffocate, it's painful, right? But of course different kind of pain than being injured or sick. What I'm wondering is, if the "painful" (...
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How many NOD like receptors in Human?

This is pretty specific question maybe. Anybody have an estimate? For Toll Like Receptors there are something like 10... http://www.jbc.org/content/276/4/2551.long I'm only finding NOD1 and NOD2 => ...
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GPCRs: Gi and Gs

GPCR = G-protein coupled receptor Gi = G inhibitory alpha subunit Gs = G stimulatory alpha subunit Are there structural differences between Gi and Gs subunits (secondary structure)? Or is it just ...
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Why is there only adrenoreceptors and no active adrenergic innervation in bronchus and uterus?

Our bronchus and uterus has beta adrenoreceptors, but they have no active sympathetic nervous system innervation in these organs. Was there a sympathetic innervation in trachea and uterus, earlier, ...
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How precisely can we sense temperature differences?

We have thermoreceptors, thus we can sense temperature (both warm and cold). I'm interested in the sensitivity of our thermoreceptors - What is the smallest temperature difference that we can sense? ...
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194 views

Why are skin tactile receptors considered to be phasic receptors?

A phasic receptor by definition is one that quickly adapts to change. In terms of neuron firing, this means that it does not trigger another firing because the receptors are used to the stimulus. But ...
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Is there a specific mechanism for the delivery of pain medication?

For example, when one takes aspirin or ibuprofen does the chemical get dispersed to all pain receptor? My question really is, how does the chemical know where to target in the body? I figure wherever ...
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439 views

Redheads and pain receptors

I remember reading this in a biology textbook, and decided to do a little digging. Redheads have a lower sensitivity to some pain and a higher sensitivity to other compared to people of other colored ...
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Where do the phosphate units come from when EGF units dimerize?

Upon EGF binding, EGFR units dimerize and cross-phosphorylate. The phosphate groups are transfered to intracellular c-terminal tyrosine rich regions. Where do the phosphate units come from in this ...
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Receptors for red and far-red light in plants: Shade avoidance

Franklin (2009) describes how plants use the ratio of the red wavelength (660-670nm) over the far-red wavelength (725-735nm) (R:FR) in order to avoid shading. My question is: which receptor is ...
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Which classes of drugs (filed by their pharmacology) induce a release of β-endorphin?

Which classes of drugs (filed by their binding sites) induce a release of β-endorphin? I know of agonists of the nAChRs and 5-HT1A and ethanol. Are there any others? Please cite journal articles ...
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Do SSRIs downregulate or upregulate the 5-HT3 receptor?

What effect do SSRIs have on the expression of the ligand-gated ion channel, the 5-HT3 receptor?
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Which Receptors are Involved in the antidepressant effects of SSRIs?

From what I've read the major receptor subtypes involved in the antidepressant effects of SSRIs are: 5-HT1A 5-HT2C 5-HT3 5-HT6 Please cite journal articles to back up your claims, I don't want any ...
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2k views

Molecular cause of cramps, spasms and strengthening in muscles? (incl. intro to muscle contraction)

When motor neurons are stimulated to trigger an action potential, this potential propagates down the spine, eventually reaching a neuromuscular junction, causing the release of acetylcholine (ACh). ...
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What Role Antagonists Play in the Study of Drugs?

I am pretty unfamiliar to pharmacology. I'm doing a research on drug abuse, particularly opioids' mechanism of action. I encountered several times evidences that come from studies using antagonists ...
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Are SLC52A2 and GPR172A really the same?

The official HUGO gene nomenclature page says that GPR172A (Gamma-hydroxybutyrate receptor) and SLC52A2 (riboflavin transporter, member 2) are the same. The sequence reported by Andriamampandry seems ...
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If a receptor is inhibited throughout embryogenesis, could there be observable phenotypic differences in the adult?

So I read a journal article entitled "Maternal hypoxia and caffeine exposure depress fetal CV function during primary organogenesis" (Momoi, et al., 2012) and in essence the article speaks of the ...
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Do serotonergic (5-HT2A-mediated) psychedelics elicit stimulant effects?

I know that 5-HT2A partial agonism is the key mechanism of action of serotonergic psychedelics but I also know that some research (e.g. the selective (no activity on any other known receptor sites) 5-...
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336 views

Does the NMDA antagonist, Memantine that's used to prevent Excitotoxicity cause brain damage?

Does the NMDA antagonist, Memantine that's used to prevent excitotoxicity in Alzheimer's disease (AD) and Dementia with Lewy Bodies (DLB) cause brain damage? I know that in rodents NMDA antagonists ...
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Are all Autoreceptors Downregulated by their Respective Endogenous Ligands?

I know that the 5-HT1A and $\alpha$2 adrenoreceptors receptors serve as autoreceptors for serotonin (5-HT) and norepinephrine respectively and are down-regulated by repeat exposure to their respective ...
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What is the cannabinoid autoreceptor?

"Is there a cannabinoid autoreceptor? And if so what is the cannabinoid autoreceptor?" (i.e. is the cannabinoid autoreceptor CB1, CB2 or is it one of the G protein coupled receptors, GPR18, GPR55 or ...
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Does regulate always mean suppress when it comes to heteroreceptors?

Do heteroreceptors always suppress the release of the neurotransmitter they regulate upon their (the heteroreceptor's) activation?
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Are single-celled organisms capable of learning?

I've read that the amoeba is capable of learning. Since these protists have no nervous system, it's safe to assume that even highly simplified learning mechanisms of the Aplysia are miles off in the ...
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Why doesn't a substance like loperamide promote analgesia?

Loperamide is frequently used to slow gastrointestinal motility. It is available over the counter (in the US, I don't know about elsewhere) without any regulations whatsoever, yet it's derived from ...