ForumGeneral Discussion ► Rant about your interests
Rant and infodump about your special interests/fixations/something you're just really passionate about.
Sorry I couldn't come up with a better title.
Long posts about your fixations :)
  
I love playin' bass. Something about it makes me so much happier than any other instrument or hobby could.
  
Planes, and trains. Now, I only need Automobiles to complete the set.
  
Vimneo gaems and memes
  
anime and manga
  
gerard way :D
  
Tell me more about this Werard Gay person.
  
MintyTea said:
Rant and infodump about your special interests/fixations/something you're just really passionate about.
Sorry I couldn't come up with a better title.
Pick a medicine. Don't question it, just pick a medicine.
  
Tell me more about this Werard Gay person.

he's cool. im doing my english assignment on him.
  
Your teacher is gonna think you're awesome. Good idea on doing a report on someone you enjoy,
  
we had to do it on someone we thought was inspirational.
i may have brought out the ex-emo in my teacher tho XD
  
Ohh, reminds me. Perfect thread for it too. Turns out my English teacher's ex-boyfriend was a big Primus fan. I found out because I was talking about Frizzle Fry to her today and she knew what it was too. That was cool.
  
ooh fun
  
Pick a medicine. Don't question it, just pick a medicine.

Visine. You know the rant I expect.
  
Coldfrost said:
Pick a medicine. Don't question it, just pick a medicine.

Visine. You know the rant I expect.
Okay. I'll get to what you want at the end, because there's a lot here.

So both on and in every cell in your body, there are structures called receptors. Receptors are made of proteins; very large chemicals made up of repeating units of other chemicals called amino acids. Receptors can be imbedded in the membrane of a cell or they can be freely floating within the cytoplasm of the cell. Almost every time a biological chemical (e.g. histamine, serotonin, dopamine, etc.) exerts an effect on any part of your body (lungs, brain, stomach, etc.), it does so through interacting with (i.e. forming a chemical bond with) a receptor. When a chemical binds to a receptor, we call it a "ligand" and receptors are usually named after their ligands: serotonin receptors, dopamine receptors, etc. The ligands that your body makes itself are called "endogenous ligands" and ligands that can enter your body from the environment are called "exogenous ligands". Exogenous ligands can come from many places, for instance, poisons or bioactive chemicals from plants, or they can be medicines. In fact, most medicines are exogenous ligands that bind to receptors so that we can exploit our body's own functions when we want. You can think of receptors as switches, more specifically as dimmer-switches. A ligand that turns on the switch all the way is called an "agonist". A ligand that turns on the switch only part of the way is called a "partial agonist". A ligand that turns off the switch is called an "antagonist". When an agonist binds to a receptor, it changes the entire shape of the receptor and that change in shape sets off a chain of reactions within the cell that eventually results in an overall biological change: when serotonin binds to certain serotonin receptors in your stomach and intestines, it changes the shape of the serotonin receptors and that sets off a chain of reactions that eventually results in nausea or even vomiting.

So, Coldfrost asked about Visine. Visine is the brand name of a medicine called tetrahydrozoline that comes in eyedrops that you put in your eyes to relieve redness, such as when you're allergic to cats and a cat rubs against your face and turns your eyes red. Now, there's a class of receptors called adrenergic receptors. Your endogenous agonists for adrenergic receptors are chemicals epinephrine (aka adrenaline) and norepinephrine. Adrenergic receptors can be further divided into Alpha1, Alpha2, Beta1, Beta2, Beta3 receptors. Tetrahydrozoline binds to Alpha receptors; both the 1 and 2 subtypes. When you put it in your eyes, it binds primarily to Alpha1 receptors to relieve the redness. I'll get to that in a sec, but let's start with where the redness came from. For that we'll have to get into histamine for a bit.

Onto histamine: Let's say you're allergic to cats and a cat rubs against your face. Various chemicals present on the cat's fur, i.e. the allergens, get into your eyes. The allergens interact with a type of white blood cells called "mast cells". When the mast cells are activated by the allergens, they release histamine. To cause the redness in your eyes, histamine will act as an endogenous agonist and bind to a type of histamine receptor called the H1 receptor (there are other histamine receptors too; H1-4). The H1 receptor is located all throughout your body, but in the context of your eyes turning red, we're gonna focus on the H1 receptors on the cells of the blood vessels in the whites of your eyes.

First take a look at this picture. This shows the different layers of a blood vessel. The endothelium is a cylindrical sheet of cells through which your blood flows. Surrounding that is another layer called the tunica intima and surrounding that is the tunica media. The tunica media is a layer of smooth muscle cells. The smooth muscle of the tunica media can contract to decrease the diameter of the endothelium (vasoconstriction), or they can relax to increase the diameter of the endothelium (vasodilation). This relaxation and contraction is mainly mediated by the level of calcium ions inside the cell. Increased calcium leads to constriction. Decreased calcium leads to dilation. When histamine binds to the H1 receptor in the endothelium layer, it causes the smooth muscle of the tunica media to relax and cause vasodilation.

Now take a look at this picture. This is a cartoon drawing of three different histamine receptors. This isn't a real representation of a cell, but look all the way on the left to where the H1 receptor is. The H1 receptor is a type of receptor called a G-Protein Coupled Receptor or GPCR. There's a lot of different GPCRs and they're all coupled to various different G proteins. The H1 receptor is coupled to the Gq protein. When histamine binds to the H1 receptor, it changes the shape of the receptor and releases the Gq protein. The Gq protein comes into contact with another protein called Phospholipase C (PLC). A chemical called phosphatidylinositol biphosphate (PIP2) then reacts with PLC and PLC turns PIP2 into another chemical called inositol triphosphate (IP3). When IP3 (represented here as InsP3) is produced in the endothelial cell, it travels to a structure in the cell called the endoplasmic reticulum and releases calcium ions (represented by the red dots) stored within the endoplasmic reticulum. The calcium ions are now released into the cell. These calcium ions then interact with a protein called calmodulin (represented as CaM in this picture). Calmodulin activates a protein called Endothelial Nitric Oxide Synthase (shown as eNOS in the picture). eNOS synthesizes nitric oxide (NO) and the nitric oxide diffuses out of the endothelial cell and travels to the smooth muscles in the tunica media. Now look at this picture. The square shaped cell represents the endothelial cells and the kinda oval shaped cell represents the smooth muscle cells of the tunica media. The nitric oxide (NO) diffuses out of the endothelial cell and into the smooth muscle cell. NO then interacts with a protein called soluble guanylyl cyclase (sGC). When sGC is bound to NO, another chemical called guanosine triphosphate (GTP) binds to it as well and is turned into a chemical called cyclic guanosine monophosphate (cGMP). Following the picture, we can see that cGMP goes to something called Cav3.x, which is a type of protein called a "voltage gated calcium channel" specifically of the 3 family (there are subtypes of the 3 family, hence the 3.x). When cGMP binds to the 3 family voltage gated calcium channels, it turns them off and prevents them from letting calcium ions into the smooth muscle. As of now, the blood vessels in your eyes are dilated and turning your eyes red. This all started because that damn cat rubbed against your face and made your mast cells release histamine.

But now let's say that cat rubbed against your face 15 minutes before you have to go to court for a child custody hearing. Your eyes are red as fuck and you don't want the judge to see you have bloodshot eyes because they might think you're on drugs and refuse you custody of your child. How can we make your eyes stop being red? Remember, histamine is the chemical that kicked this all off. Could you take an antihistamine to prevent histamine from binding to the H1 receptor? Sure, you could take some Claritin or some Benadryl, but that would take about 30 minutes to an hour before your eyes became white again because it has to first get absorbed through your intestines then turn off the H1 receptor and then your body would have to use up the IP3, calcium, and NO already in play making your eyes red.

What we could do to make the redness go away faster is to put Visine (tetrahydrozoline) in your eyes. Tetrahydrozoline binds to and activate Alpha1 (hence it's an exogenous agonist) receptors located directly on the smooth muscles in the tunica media. Alpha1 receptors are also GPCRs coupled to a Gq protein just like the H1 receptor located in the endothelial cells of the blood vessels. Just like the H1 receptor, when the Alpha1 receptor is activated, it releases the Gq protein, the Gq protein turns on phospholipase C (PLC), PLC turns phosphatidylinositol biphosphate (PIP2) into inositol triphosphate (IP3) and IP3 releases calcium ions from the endoplasmic reticulum. Only THIS TIME we're not in an endothelial cell and we're NOT activating calmodulin and we're NOT activating eNOS (endothelial nitric oxide synthase). Instead, this time, we're in the smooth muscle of the tunica media. So remember, this time we've increased the calcium ion levels inside the smooth muscle cell, not the endothelial cell, so we have no nitric oxide to produce. Instead, when calcium on levels are increased in smooth muscle cells, they cause the smooth muscle cell to contract and produce vasoconstriction.

That's the difference. An antihistamine would have to stop the entire process kicked off by histamine binding to the H1 receptor. Visine (tetrahydrozoline) instead directly causes vasoconstriction while the process caused by histamine binding to the H1 receptor is still happening. The end effect on calcium from the H1 receptor was to stop letting calcium into the smooth muscle cell. Your smooth muscle cells have their own internal storages of calcium though. This time we're telling the smooth muscle cells to release their own calcium. It's kinda like telling someone "Lost your job and no more money coming into your household? Just go dig up the box full of cash that you buried in your backyard."

So now the smooth muscle cells in the tunica media are contracted and causing vasoconstriction and now your eyes aren't red anymore and you're ready to walk into the courtroom and convince the judge to give you custody of your kid because you don't have eyes so red that you look like a pothead.

On that note, what Coldfrost was getting at is that THC can cause vasodilation too and also turn your eyes red. So what some savvy potheads do is they use Visine to constrict the smooth muscles in the tunica media of the blood vessels in their eyes to make them stop being red.
  
i am tempted to pull a hoylecake and yell at you for quoting the post above you
  
i am tempted to pull a hoylecake and yell at you for quoting the post above you
Idk how that started but let’s be totally clear: that is not a rule nor is it in anyway contrary to forum etiquette and you should all stop yelling at each other for it. In fact, now I’m gonna start exclusively doing that. Think of it as exposure therapy.
  
Pick a medicine. Don't question it, just pick a medicine.


(hey someone with parallel interests to mine!!! willing to discuss another?)
Lithium
  

On that note, what Coldfrost was getting at is that THC can cause vasodilation too and also turn your eyes red.
Oh no I was getting at that using them habitually will actually worsen your irritation and redness when you stop using them. It will actually cause your blood vessels to enlarge, so your eyes will always look red when they don't have visine in them.
  
thank you for the very long biology lesson. honestly I only read the first 3 paragraphs but my eyes are watering trying to read all that stuff I don't really understand
  
Coldfrost said:

On that note, what Coldfrost was getting at is that THC can cause vasodilation too and also turn your eyes red.
Oh no I was getting at that using them habitually will actually worsen your irritation and redness when you stop using them. It will actually cause your blood vessels to enlarge, so your eyes will always look red when they don't have visine in them.
Ooohhh shit you’re right! Yeah, it can cause some pretty intense downregulation of the alpha1‘s. That happened to a couple of my friends when we were in high school and it got pretty funny. Sometimes it screwed them over when they weren’t stoned, other times it saved them when they were.
azerty said:
Pick a medicine. Don't question it, just pick a medicine.
(hey someone with parallel interests to mine!!! willing to discuss another?)
Lithium
Mind if I get to it tomorrow? Also will preface by saying lithium’s exact mechanism of action isn’t too well known but I’ll hit you with what I do know.
thank you for the very long biology lesson. honestly I only read the first 3 paragraphs but my eyes are watering trying to read all that stuff I don't really understand
I love giving long bio lessons.
  
Should I give a rant about Lithium, the metal, from a materials perspective?
  
Go for it, that sounds great.
  
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