Throughout the 19th century Morphine was used as an anesthetic, a sleep medication, and an anti-diarrhea agent. Chemists with the Bayer Company, a German pharmaceutical company, developed heroin, then aspirin while searching for a medical alternative to morphine, in the late 1800s. Heroin is used to treat morphine addiction - until it is realized that the addictive properties are stronger that with morphine All uses of heroin are outlawed by 1924. Acting as antagonists, opiates bind to endorphin receptor sites. Neurons with endorphin receptors are located in the spinal cord, midbrain and limbic systems, and regions of the brain stem.
Opiate use causes tolerance, then physical dependence or addiction.
With increasingly larger doses of these drugs, respiratory centers of the brain are inhibited. Addicts generally have poor eating habits, loose weight, and suffer vitamin deficiencies. Overdose - Large doses of opiates inhibit respiratory centers in the brain stem. With high levels of opiates the automatic process of breathing is lost. Overall, stimulants increase the amount of excitatory neurotransmitters in the brain which causes a higher frequency of neural impulses.