Final answer:
Opiate drugs similar to endorphins that mimic their euphoric effects are called agonists, and they interact with opioid receptors to change pain perception and can lead to abuse.
Step-by-step explanation:
Opiate drugs that have molecular structures similar to endorphins and mimic their euphoric effects in the brain are considered agonists. When these drugs bind to opioid receptors, they produce pain relief and feelings of euphoria akin to the natural endorphins the body creates.
By attaching to these specific receptors in the brain, spinal cord, and gastrointestinal tract, agonists like opiates change the way a person experiences pain, often leading to a high potential for abuse. Examples include morphine, codeine, and heroin, as well as synthetic versions like hydrocodone and oxycodone.