[The interaction between nucleus accumbens and amygdala in accelerating the release of enkephalins and beta-endorphin].
The functional relations between nucleus accumbens and amygdala were investigated with intracranial microinjection, push-pull perfusion and radioimmunoassay in the rabbit. Microinjection of morphine 20 micrograms into nucleus accumbens increased the immunoreactive (ir) enkephalin content in amygdala perfusate from a control level of 0.43 +/- 0.43 fmol/0.5 ml (normal saline group) to 61.6 +/- 16.3 fmol/0.5 ml (P less than 0.01); and ir-beta-endorphin content from 1.88 +/- 0.98 fmol/0.5 ml to 4.80 +/- 1.12 fmol/0.5 ml (P less than 0.05). On the other hand, microinjection of morphine into amygdala increased the release of ir-enkephalins (2.41 +/- 1.41 vs 34.6 +/- 8.4, P less than 0.01) and ir-beta-endorphin (1.79 +/- 0.64 vs 5.58 +/- 1.39 P less than 0.05) in the perfusates of N. accumbens. The results indicate the existence of reciprocal reinforcement of opioid release between the two nuclei, which may take part in a putative positive feedback mechanism in the cerebral analgesic system.
Ma
Q P
QP
Neuroscience Research Center, Beijing Medical University.
Han
J S
JS
D000679:Amygdala / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D004745:Enkephalins / Q000378:metabolism*; D008297:Male; D008845:Microinjections; D009020:Morphine / Q000494:pharmacology; D009619:Nociceptors / Q000502:physiology; D009714:Nucleus Accumbens / Q000378:metabolism / Q000502:physiology*; D011817:Rabbits; D001615:beta-Endorphin / Q000378:metabolism*
D004745:Enkephalins; D001615:beta-Endorphin; D009020:Morphine