13
votes
Accepted
Why do Hot/Cold drinks taste sweeter once returning to room temperature?
Generally, cold suppresses sweetness. As an example, consider soft drinks that are usually served cold: they taste sweeter when warm (like you said with your examples of drinks).
Our taste receptors ...
- 2,603
9
votes
Why do we get sleeply after we eat?
After we have eaten... the maximum blood supply is transferred towards the digestive system so that digestion is done, and therefore the brain to does not get adequate blood supply. Am I right about ...
- 24.5k
8
votes
Accepted
How precisely can we sense temperature differences?
Short answer
Temperature differences of 0.02 degrees Celcius can be distinguished, dependent on various factors including experimental conditions and bodily location.
Background
The ability to ...
- 51.8k
8
votes
What are the effects of removing CD4 receptors?
The CD4 receptor is vital for the proper functioning of the immune system. It is found not only on T-Lymphocytes, but also on macrophages and dendritic cells. Its function on T-cells is to stabilize ...
- 4,975
6
votes
What structural features make a molecule a potent opioid receptor agonist?
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 ...
- 5,550
6
votes
Why is ACE2 not used as drug against covid?
There's a Cell pre-print by Monteil et al. (DOI: 10.1016/j.cell.2020.04.004) which argues that human recombinant soluble ACE2 protein can competitively bind to SARS-CoV-2 virus and reduce its ability ...
- 5,550
6
votes
Accepted
Same target receptor different mechanism of action?
Not necessarily!
Biased agonism
It's reasonable to start with an expectation that agonists at the same receptor have the same effect, but that's not necessarily true due to biased agonism. Biased ...
- 40.1k
6
votes
How do G proteins move?
Interpretation of the Question
The question asks how the G-protein α- and βγ-subunits move, but does not state the context or circumstances of the movement. I assume that the question is, in fact:
...
- 23.3k
5
votes
Accepted
How is adrenaline (also known as "epinephrine") a ligand?
The definition of "ligand" in the question, "a molecule or ion which donates a pair of electrons to a central transition metal ion in a complex" is clearly a more technical 'chemistry-type' of ...
- 2,348
5
votes
Accepted
Are resonances the reason receptors work?
Photoreceptors themselves dont act as oscilators, a single receptor is either 'on' or 'off' - it does not respond differently to different wavelenghts. Humans have Trichromatic vision, which means ...
- 4,356
5
votes
Accepted
Is there a reason for the lack of full RTK structures?
Large proteins are challenging for NMR: the more amino acids, the more peaks one has to assign. Peak overlap is also more likely the more amino acids you have, making assignment difficult. Some NMR ...
- 715
5
votes
How are the receptors in the thalamus weakened/shut down during sleep?
Sleep research is a big field and the answer to your question can take many forms and fill libraries. Having said that, it is not so much inhibition of the thalamus per se, but a change in firing ...
- 51.8k
4
votes
Trypsin and Cell Surface Receptors
Yes. Trypsin cleaves proteins and can do so quite indiscriminately if left on for very long. Trypsin is primarily used to cleave the proteins that cells use to adhere to each other and the plate in ...
- 1,309
4
votes
Accepted
How does receptor downregulation/upregulation work?
Both internalization (sometimes with degradation) and changes in gene expression can occur; the circumstances leading to the down regulation determine which (or both). It isn't necessary for receptors ...
- 40.1k
4
votes
Accepted
Does the dissociation of serotonin receptors and their ligands really take hours?
That paper is describing the binding between the 5HT3 receptor and some high-affinity ligand, not serotonin.
Numbers of serotonin probably vary according to the precise receptor (species, subunits, ...
- 40.1k
4
votes
Accepted
Receptors for red and far-red light in plants: Shade avoidance
As far as I know there are 5 receptors for far-red and red light which are the phytochroms(phyA-phyE) Its all about the ratio between red and far-red light.
Each phytochrom has an inactive(PR) and ...
- 174
4
votes
Is there a specific mechanism for the delivery of pain medication?
Short answer
No, orally taken painkillers act systemically.
Background
Taking a painkiller orally results in the drug being taken up into the bloodstream by the digestive system. From there it can ...
- 51.8k
4
votes
Additive property of taste
I would classify the neurological phenomenon of "taste" or "tastyness" as an emergent property (1), and therefore synergistic (i.e. not adequately explained simply by additive effects). For example, ...
- 4,571
3
votes
Neuroscience behind the crash
The "crash" effect is typically perceived as a deterioration in affect. With drugs, this deterioration happens as the drug is cleared from blood circulation, particularly cerebral circulation. With ...
- 141
3
votes
Redheads and pain receptors
I think it's best to break this question up in to two parts:
What mutations account for red hair and fair skin in humans
How might these same mutations affect pain sensation
MC1R variants & red ...
- 756
3
votes
Accepted
Why are skin tactile receptors considered to be phasic receptors?
Short answer
Slowly adapting mechanoreceptors in the skin mediate the perception of static pressure stimuli, while rapidly adapting skin receptors mediate swiftly changing (e.g., vibratory) stimuli.
...
- 51.8k
3
votes
Influenza infections and drug design
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 ...
- 14.1k
3
votes
How do we know that selective agonists are indeed selective?
Unfortunately, it's really hard in the general sense. Even for FDA-approved drugs with well-characterized mechanisms of action, the binding profiles are incomplete.
For GPCRs, it's you can run your ...
2
votes
Is there a specific mechanism for the delivery of pain medication?
Most NSAIDs derive their analgesic effects from inhibit the cyclooxygenase (COX) enzymes that produce the prostaglandin-H2 precursor to the prostaglandins that sensitize neurons to pain.
Edit: With ...
- 1,771
2
votes
Toll Like Receptors Vs Toll Receptors
In Drosophila, Toll receptors are used during embryonic development as well as innate immunity. See The Drosophila Toll Signaling Pathway by Valance, et. al.
Toll-like Receptors are pattern ...
- 4,975
2
votes
Do antagonist-receptor complexes get absorbed into the cell?
When a neurotransmitter, like serotonin, binds to it's specific receptor, the ligand-receptor complex is not phagocytosed. Picture the human cell membrane and think of the serotonin receptor like a ...
- 21
2
votes
What are the effects of removing CD4 receptors?
I think it's deathly important to note how critical CD4 is for the activation of T-helper cells, and thus a myriad of downstream immune cells such as B cells:
When an APC presents an antigen through ...
- 8,081
2
votes
Accepted
Does anyone know of any resources that detail an extensive number of receptor types, their effects, and signalling pathways?
From the comment section:
The IUPHAR database is one of the most extensive database for receptors and ligands. It also contains a lot of additional information and direct references to the literature....
- 2,883
2
votes
How long does it take for a blocked dopamine receptor to be broken down by the body?
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 ...
- 1,515
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