The autonomic nervous system is the part of the nervous system that controls muscles of internal organs (such as the heart, blood vessels, lungs, stomach, and intestines) and glands (such as salivary glands and sweat glands).
Naltrexone is also used to reduce cravings for alcohol. Scientists are unsure how it works in relation to alcohol but it has been shown to reduce desire and cravings by blocking the same receptors that create feelings of pleasure when opioids are taken.
Naltrexone hydrochloride is a pure opioid antagonist. It markedly attenuates or completely blocks, reversibly, the subjective effects of intravenously administered opioids. When co-administered with morphine, on a chronic basis, Naltrexone blocks the physical dependence to morphine, heroin and other opioids.