Evidence for the independence of brainstem mechanisms mediating analgesia induced by morphine and two forms of stress

摘要: Abstract Exposure to inescapable footshock stress causes potent analgesia in the rat. According several criteria, prolonged, intermitent elicits mediated by opioid peptides, whereas brief, continuous produces non-opioid analgesia. We now report that these neurochemically discrete forms of also have different neuroanatomical bases. Electrolytic lesions damaging greater than 85% n. raphe magnus (‘complete’ NRM lesions), but not same size causing less damage (partial lesions) significantly reduce only form In animals, complete and partial disrupt morphine analgesia; however, our analyses indicate this effect is b substrate involved either These results support existence multiple endogenous mechanisms a complex role systems.