PSY 3142 Lecture Notes - Lecture 13: Methadone, Periaqueductal Gray, Opioid Antagonist

• School: University of Ottawa
• Department: Psychology
• Course: PSY 3142
• Professor: Philip Wall

Document Summary

All four types of opioid receptors are also coupled to inhibitory g proteins (gi) that inhibit adenylyl cyclase, which normally synthesizes the second message camp. Reduced camp and thus decreased function of camp dependent portion kinase may be partly responsible for opioid induced ion channel changes. Pain has two components: (1) rst or early pain with an immediate sensory competent. Signals are carried by militated a neurons, which conduct action potentials quickly. (2) emotional, later pain. Signal carried by thin and unmylenated c bres and transmission is slower. Early pain: spinal cord (via spinothalamic tract) pvl nucleus thalamus somatosensory cortex. Opioid drugs bind to opioid receptors and mimic the inhibitory action of the endogenous opioids at many stages of pain transmission. Small inhibitory interneurons release endorphins that inhibit the spinal projection neurons. Morphine can act directly on those same opioid receptors to inhibit transmission of pain signals to higher brain centres.