First, it should be noted that, Mexicans can be just as sensitive to chile heat as anyone else. So, a properly prepared Mexican dish should not require an antidote. If, however, you inadvertently sample a tortilla chip that has been dipped into a salsa that was prepared with the specific goal of bringing tears to your eyes and sweat to your forehead, the best antidote is a dairy product such as milk or cream, and starchy foods such as rice, beans and sopaipillas which tend to absorb the capsaicin. A sugar-laced cola is also helpful. Studies have indicated that the ingestion of chiles releases endorphins in the brain.
Endorphins are chemical compounds designed to act much as does any pain killer such as morphine.
So, when the heat in your mouth signals your brain that something painful may be occurring, it reacts by producing a small amount of a very potent drug-like substance that creates an overall feeling of pleasure. I do not find the same effect to be present, at least not to the same degree, in other chile-laced cuisines such as those of Sichuan and India, science notwithstanding. Perhaps it has something to do with the combination of cheese, corn, and endorphins. After all, the food of the original inhabitants of Mexico was almost entirely vegetarian and fat-free. It was not until the Spanish Conquest that fats and fatty foods were introduced.