Mu-delta opioid interactions. II: Beta-FNA inhibits DPDPE-induced increases in morphine EEG and EEG spectral power.
In the present study, the effects of beta-FNA on DPDPE-induced increases in morphine EEG and EEG power spectra were assessed. Adult female Sprague-Dawley rats were implanted with cortical EEG electrodes and permanent indwelling ICV and IV cannulae. Rats were administered ICV beta-FNA at 20 nmol or ICV sterile water. Then 18-24 h later, rats were administered ICV DPDPE at 2.5 nmol or ICV sterile water followed, 10 min later, by IV morphine at 3 mg/kg. Morphine-induced changes in EEG global (1-50 Hz) spectral parameters, the duration of morphine-induced high voltage EEG bursts, the period of EEG and behavioral excitation, and the latency to onset of slow-wave sleep were statistically analyzed using a one-way analysis of variance. beta-FNA pretreatment significantly decreased morphine-induced total spectral power seen in the DPDPE + morphine group. beta-FNA pretreatment also significantly decreased the duration of morphine-induced EEG bursts, the period of EEG and behavioral excitation, and the latency to onset of slow-wave sleep in the DPDPE + morphine group. These data, therefore, suggest that DPDPE may be increasing the effects of morphine on EEG through delta opioid receptors associated with the mu-delta opioid receptor complex.
Stamidis
H
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University of Maryland, School of Pharmacy, Department of Pharmacology and Toxicology, Baltimore 21201.
Young
G A
GA
D000700:Analgesics / Q000037:antagonists & inhibitors*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004569:Electroencephalography / Q000187:drug effects*; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000037:antagonists & inhibitors*; D005260:Female; D007276:Injections, Intraventricular; D009020:Morphine / Q000494:pharmacology*; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D017465:Receptors, Opioid, delta / Q000378:metabolism; D017450:Receptors, Opioid, mu / Q000378:metabolism; D012890:Sleep / Q000187:drug effects
D000700:Analgesics; D004745:Enkephalins; D009292:Narcotic Antagonists; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D009271:Naltrexone; C024524:beta-funaltrexamine; D009020:Morphine; D020881:Enkephalin, D-Penicillamine (2,5)-