Differential effects of chronic antidepressant treatments on micro- and delta-opioid receptors in rat brain.
We performed an autoradiographic study of [D-Ala(2),MePhe(4),Gly-ol(5)]enkephalin (DAMGO)-sensitive [(3)H]naloxone binding to micro-opioid receptors and of [(3)H][D-Pen(2),D-Pen(5)]enkephalin (DPDPE) binding to delta-opioid receptors in the rat brain after 4- or 21-day treatments with paroxetine, reboxetine and moclobemide to investigate the participation of these receptors in the adaptive mechanisms occurring during the delay of action of new generation antidepressants. Paroxetine increased micro-opioid receptor binding site density in cingulate and insular cortices, dorsal endopiriform nucleus (4 days) and olfactory tubercle (21 days) and decreased it in thalamus (21 days). Reboxetine increased it in amygdala (4 days), hippocampus and thalamus (21 days) and decreased it in dorsal raphe (4 days). Moclobemide increased it in hippocampus (4 days) and decreased it in anterior olfactory nucleus, frontal cortex, amygdala and hypothalamus (21 days). Moclobemide increased delta-opioid receptor binding site density in frontal cortex and amygdala (4 days) and decreased it in amygdala and colliculi (21 days). Opioid receptors displayed distinct patterns of adaptations in response to the three antidepressants studied.
Vilpoux
Catherine
C
Unité de Neuropsychopharmacologie Expérimentale, CNRS UPRESA 6036, IFRMP No. 23, UFR de Médecine-Pharmacie, 22 Bd. Gambetta, 76 183 Rouen, Cedex, France.
Carpentier
Céline
C
Leroux-Nicollet
Isabelle
I
Naudon
Laurent
L
Costentin
Jean
J
D000818:Animals; D000928:Antidepressive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001345:Autoradiography; D001665:Binding Sites; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / Q000494:pharmacology; D020881:Enkephalin, D-Penicillamine (2,5)- / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D008297:Male; D020912:Moclobemide / Q000008:administration & dosage / Q000494:pharmacology; D009025:Morpholines / Q000008:administration & dosage / Q000494:pharmacology; D017374:Paroxetine / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077593:Reboxetine; D017465:Receptors, Opioid, delta / Q000187:drug effects* / Q000378:metabolism; D017450:Receptors, Opioid, mu / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors
D000928:Antidepressive Agents; D009025:Morpholines; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D017374:Paroxetine; D020881:Enkephalin, D-Penicillamine (2,5)-; D000077593:Reboxetine; D020912:Moclobemide