So what exactly are opioids and what is their scientific function? Opioids are substances which act on opioid receptors to produce morphine-like affects. Opioid drugs are medicated to cure severe acute pain. Opioids and opiates must bind to proteins to elicit a physiological response. This occurs when opiates bind to opioid receptor proteins in order to activate signals inside the cell. So, when a person injects, swallows, or snorts an opioid, the drug binds to opioid receptors all over the body which is why and how a person's mood begins to change, their pupils shrink, blood pressure drops and digestion slows.
When opioids bind to the receptors in the brain they activate different chemical activity. Pain relief is a result from signals sent by the opioid receptors through brain cell membranes. While some people experience pain relief others may experience restricted breathing. When a person consumes an opiate they immediately feel pain relief but you also see a drop in breathing rates as well as blood oxygen levels. This second pathway of chemical activity is extremely dangerous and is the main reason people die from opioid use. During this second cascade of chemical activity the opiate activates a second brain pathway where breathing can potentially stop.
In addition to its intended purpose of functioning as pain killers, opiates stimulate strong feelings of euphoria which is an intense rush of addictive pleasure. Opioid users seek this sensation repeatedly building a tolerance to the opiate resulting in opioid abuse. The body then grows dependency on the drug making individuals feel as though they cannot go through their everyday life without consuming of the drug. Which is why the US cannot see the end to this opioid overdose epidemic.