Abstract
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 IP) 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 IP) 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.
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Received: 6 October 1997/Final version: 2 March 1998
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Olive, M., Maidment, N. Repeated heroin administration increases extracellular opioid peptide-like immunoreactivity in the globus pallidus/ventral pallidum of freely moving rats. Psychopharmacology 139, 251–254 (1998). https://doi.org/10.1007/s002130050712
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DOI: https://doi.org/10.1007/s002130050712