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 ...
- 24.7k
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 ...
- 4,985
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 ...
- 5,568
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 ...
- 5,568
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 ...
- 43.9k
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:
...
- 24.3k
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
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 ...
- 4,391
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 ...
- 2,368
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 ...
- 52.3k
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 ...
- 43.9k
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, ...
- 43.9k
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
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, ...
- 4,671
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 ...
- 14.2k
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 ...
3
votes
Why is the SARS-CoV-2 target receptor ACE2 not endocytosed when bound physiologically?
So, the question is
Why doesn’t the enzyme ACE2 — SARS-CoV-2’s target receptor — undergo endocytosis when bound by its physiological ligand, angiotensin II?
(Clarithin-mediated) endocytosis of "...
- 3,052
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 ...
- 4,985
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
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
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....
- 2,903
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 ...
- 8,101
1
vote
Accepted
Is there a data base, tool or method I can use to find out which of my genes code for cytokine receptors?
I'm sure there are many ways to go about this (including literature research via PubMed), but for a start, I searched the GO term data base which, for the search term "cytokine receptor activity" ...
- 111
1
vote
Accepted
James Allison's T-cell discovery technique
Well so here's the paper, at least on Dr. Allison's side. Mind you, the discovery is shared by a number of individuals for their combined effort.
So what they did is took mice and immunized them with ...
- 8,101
1
vote
What is the purpose of the viscous gel in the Pacinian corpuscle?
Short answer
The adaptation process in Pacianian corpuscles (PCs) is mediated via the outer capsule. This capsule is an onion-like structure that quickly molds itself to pressure stimuli, thereby ...
- 52.3k
1
vote
Are resonances the reason receptors work?
Receptors accept a huge variety of molecules as ligands.
In the example that you outline the receptors are called photoreceptors. The ligands for photoreceptors are generally contain alkene backbones ...
- 623
1
vote
Is the Insulin Receptor Considered an Enzyme?
Yes, the insulin receptor can be viewed as an enzyme, since it catalyzes a reaction -- phosphorylation of tyrosine residues on its substrates. But since the protein has multiple functions, it's ...
- 5,675
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