I'm planning on researching this, but I would like to see if anyone already knows.

I am curious as to what chemical reactions and mechanisms and such fun things are occuring inside the body to produce tolerances and physical addictions.

I am aware that its probably different for different drugs, which is why just for now I want to focus on 3 drugs: Laughing Gas, Pot, and Heroin.

As far as I know, nobody gets an NO2 tolerance. Also, as far as I know, it is not at all physically addictive. So how come? What makes it different from drugs which will cause tolerance to develop?

If you smoke enough pot, you will gain a tolerance. Why? Whats happening in your body that causes this?

Heroin use can be addictive and cause tolerance. What makes opiates physically addictive? What causes tolerance ... I would assume it would be something different then what causes tolerance in pot or mushrooms, or speed, that all of these drugs have different causes of tolerance, but similarities as well.

Finally, if tolerances and addictions are the result of chemical processes in your body, couldn't we find a way counter these processes before they develop? While using the drugs simultaneously, of course.

I'm going to be researching this on my own, but if you know something feel free to post it.

many addictions to drugs focus on neurotransmitters, for example dopamine and seratonin.

i think it is probably possible to build a tolerance to nitrous oxide, it just doesnt happen because of the nature of the drug

http://learn.genetics.utah.edu/units/addiction/drugs/mouse.cfm

nitrous feeds off of your bodies vitamin b-12 supply, so in that sense, you can develop a tolerance...it wont feel as strong later on in the session, because your b12 lvls will be lower. dose up on lots of vitamin b, a few days before using , and its much more enjoyable.

In studies done with rats, it was shown that large amounts of vitamins C and E can effectively reduce both the tolerance and the neurotoxicity of MDMA.

There are ways to counter a drug's detrimental effects as well as the tolerance your body builds to it. We just need well-funded scientific studies to discover what certain mix of chemicals can accomplish these goals, but in the state of fascist suppression of research we live in today that's very difficult to do.

There are soooo many experiments that have done what you propose to do.

You are correct about that NO2 though, nobody really builds a tolerance to that. But then again, most people die pretty quickly after being exposed to NO2.

There are a few main mechanisms for drug addictions.
Heroin causes a large amount of endorphins to be released in a very short period of time, esp. if you shoot it. As with most of the bodies chemicals, endorphins are controlled by negative feedback, meaning that if the blood is saturated with endorphins, they will down regulate their own production. Because they are downregulated, they are not produced as frequently without the presence of heroin, causing physical pain/shittyness.

Cocaine addiction works by operant conditioning using a token economy. Yes, the same conditioning that Skinner used to train dogs. Basically, cocaine causes reward channels to become flooded with D1 and D2 agonists. Coincidentally(sort of), this mechanism is also how humans develop behaviorily. An example of this would be doing chores to get allowance. You want the reward, so you do the chores, and when you get the money, your brain gives you a dopamine cookie for increasing your survival rate. Cocaine gives you a dopamine wedding cake. And so, your body becomes conditioned to the idea that cocaine = "great job".

Weed doesn't develop withdrawals though. The only "withdrawal" symptoms are birthed from the day to day habit of smoking weed. Humans don't like to change their psychological schedules when they work well for them. Weed is a good, fun time waster, and when a person who has stopped smoking is bored, the first thing on their mind will usually be, "let's smoke weed b/c weed always takes away boredom". Cognitive dissonance can probably also be factored in here.