Repeated heroin administration increases extracellular opioid peptide-like immunoreactivity in the globus pallidus/ventral pallidum of freely moving rats.
Microdialysis was used to investigate the effects of heroin administration on extracellular opioid peptide levels in the globus pallidus/ventral pallidum of freely moving rats. Two injections of heroin (0.6 mg/ kg i.p.) were given 3 h apart. The first injection had no significant effect on opioid peptide levels, but the second injection produced a transient yet significant increase (+268%) in opioid peptide-like immunoreactivity in pallidal dialysates, peaking 1 h after injection. This effect was blocked by administration of naloxone (3 mg/kg i.p.) prior to the second injection. The implications of these data are discussed with regards to the role of the endogenous opioid peptide system in opiate reward.
Interdepartmental Neuroscience PhD Program, University of California at Los Angeles, 90024, USA.
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D000704:Analysis of Variance; D000818:Animals; D005917:Globus Pallidus / Q000187:drug effects* / Q000378:metabolism; D003932:Heroin / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D017551:Microdialysis; D009020:Morphine / Q000378:metabolism; D018847:Opioid Peptides / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018847:Opioid Peptides; D003932:Heroin; D009020:Morphine