Question

_______ are chemicals released by the body that block the release or uptake of neurotransmitters necessary to transmit pain sensations to the brain. hyperalgesics endogenous opiates corticosteroids algesic opiates

Answer 1

The answer is the endogenous opiate. 
The human body naturally produces its own opiates like substances and uses them as neurotransmitters. These substances include endorphins, enkephalins, and dynorphin, often collectively known as endogenous opioids. Endogenous opioids modulate our reactions to painful stimuli.