How Does Heroin Affect the Brain?
Heroin enters the brain, where it is converted to morphine and binds to receptors known as opioid receptors. These receptors are located in many areas of the brain (and in the body), especially those involved in the perception of pain and in reward. Opioid receptors are also located in the brain stemimportant for automatic processes critical for life, such as breathing, blood pressure, and arousal. Heroin overdoses frequently involve a suppression of respiration. After an intravenous injection of heroin, users report feeling a surge of euphoria (rush) accompanied by dry mouth, a warm flushing of the skin, and a heaviness of the extremities. Following this initial euphoria, the user goes on the nod, an alternately wakeful and drowsy state. Mental functioning becomes clouded. Users who do not inject the drug may not experience the initial rush, but other effects are the same. With regular heroin use, tolerance develops. This means the abuser must use more heroin to achieve the same inten
