(GI) Physiology & Pharmacology Tutorial: All about Acid secretion, proton pump inhibitors and H2 blockers!

All well-nigh ACID!

A lot of pathology of the GI portion is due to over secretion of acid. This causes GERD aka acid ebb., peptic ulcer disease, a gastrin releasing tumour called Zollinger-Elson sickness and much more!

Lets talk near acid and how it is released:

After we consume, the food in our stomachs of necessity to be broken down by Acid (H+). Various hormones, neurotransmitters and peptides ~ by heart secreted in order for this performance to take this place. 

Step by step process of how acid is secreted:

1. After wear away, the food goes into our inclination causing it to stretch and spread.

2. The vagus nerve in our inclination gets stimulated when stretched -> back which it stimulates a second neuron-> what one. releases GRP (Gastrin binding protein)-> GRP binds and stimulates G cells-> that release gastrin.

3. Gastrin->stimulates ECL cells (aka Enterochromatin like cells)-> ECL cells absolution Histamine. Both Gastrin & Histamine journey to the parietal cells like untarnished ol pals. Once they reach there, they say goodbye and bind to various receptors.

4. Gastrin binds & stimulates the CCK receptor at the same time that, Histamine binds to the H2 receptor. The covering of these receptors stimulates or activates the PROTON PUMP aka H+/K+ cross-question. Remember, H+ is a proton and H+ is pricking. This is why it is called a proton interrogate, because the parietal cells pump confused protons (H+). Everytime H+ ss secreted superficies of the cell into the lumen, K+ is taken back into the parietal confined apartment. This is to balance out the charges (the two being positively charged).

5. Once H+ is released, our viands can be broken down and digested.


Proton cross-examine inhibitors (PPI): The “Prazole” race- Omeprazole, Lansoprazole.

Mnemonic: Prazole sounds like the sharp reflux causing food, Pretzel. Just form an image of something after eating an oily and sweet pretzel groaning, “Oh, Omeprazole, please come to a dead lock this burning acid because of this pretzel!!”


Now that we have knowledge of what a proton pump is (solely a H+/K+ receptor). It is easier to apprehend that PPI inhibit this receptor. When this receptor is inhibited, H+ can no longer be secreted into the gastric lumen.

The reason why PPI’s are the medicine of choice and so effective in treating conditions like GERD, its because its to such a degree radical in its approach. These drugs bar the entire pump! if the cross-examine is turned off, no acid be able to be secreted at all!

Side personal estate of PPI’s: Because these drugs completely shut off this pump and no stinging can be released into the lumen. Imagine the kind of happens after we eat! The aliment cannot be broken down properly seemly? Therefore, we will have some GI lateral effects such as, nausea, gas, diarrhea and abdominal pain.

H2 blockers: The “TiDine” parents and children: CimetTiDine and RaniTiDine, and anything that ends in TiDine.

Mnemonic: These drugs allow you TwoDine in quiet and comfort! This is a virtue way to memorize or recognize these remedy names and the receptor that they repress.


You see, H2 inhibitors what one. are also used to treat GERD are used being of the kind which second choices. Why? Because they sole block the H2 receptor in the parietal small room. This means it does reduce sour to a certain extent but since the proton pump is still functioning, gastrin, acetylcholine and all those other peptides/transmitters can notwithstanding bind to their own receptors and activate the proton cross-examine. Only the H2 receptor is turned from. The patient may not get complete relief of their symptoms because of this. Because its not too radical in its approach, these drugs are frequently found over the counter.

Side furniture of Cimetidine:

1. Drug interactions. I would keep out of the way of taking this if you’re pique any other medications. Why? Well for the reason that it inhibits P-450. Remember this awful enzyme in the liver that helps metabolize and cashier down drugs for us? Well, on the supposition that this enzyme is not working sooner or later the medications we can’t have ~ing excreted out of our bodies and in return, their effects last much longer in bodies. This causes filthy side effects.

2. Anti-androgenic (aka womanizer meaning): If you’re a masculine and you would like to stay that resolved mode of action, then please avoid taking cimetidine. It blocks your dearly much loved macho man hormone, mr. androgen. Once Mr. androgen is not working, mrs.estrogen will be the first of the household. This drug be able to increase your breast size (gynecomastia), contract your libido, cause impotence and occasion discharge from your nipples (increased prolactin).

Mnemonic: When Cimetidine tells you to Come-to-dine with him, you better say ~t any to the offer!

There are lots of cases of imposition. of duplicate cold drinks.

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