Each of these receptors is involved in different brain functions. For example, mu is responsible for the pain-relieving effects of the drug morphine. The limbic system controls emotions. Opiates change the limbic system to produce increased feelings of pleasure, relaxation and contentment. The brainstem controls things your body does automatically, like breathing or coughing.
Opiates can act on the brainstem to stop coughing or slow breathing.
The spinal cord transmits pain signals from the body. By acting here, opiates block pain messages and allow people to bear even serious injuries. Now it will be easier for researchers to make opiate receptors and study how opiates affect nerve cells. This discovery may lead to other exciting developments, such as better treatments for opiate addiction.