You will find a release of norepinephrine through the descending inhibitory bulbospinal neurons that binds to alpha-2-receptors inside the dorsal horn to reduce afferent ache transmission and create analgesia. Hence, drugs like clonidine that target alpha-two receptors can affect the transmission of pain. Clonidine is dispersed in breast milk; https://emilianoswjtc.total-blog.com/the-smart-trick-of-onolidine-that-nobody-is-discussing-57392395