Morfinomimetica en substance P

One of the most important indications of morphine like drugs is severe chronic pain. The analgesia probably is effected by opiates reacting with specific binding sites in the neuronal substrate and thus interfere with endogenous opioid peptides. Recently considerable advance has been made in the research for the mechanisms of opiate analgesia. The article comes to the following model. Pain stimuli are transferred to the central nervous system via the SP containing thin primary afferent fibers. With the ends of these fibers encephalinergic neurons form axo-axonic synapses. The activity of these encephalinergic neurons results in presynaptic inhibition of the SP-ergic pain fibers, as a result of which the release of this substance is inhibited. This leads to a reduction of stimulus transference in the pain paths.