title: Diverse behavioral, monoaminergic and Fos protein responses to opioids in Warsaw high-alcohol preferring and Warsaw low-alcohol preferring rats.
abstract: Predisposition to addictions is presumably related to a dysfunction of the brain reward system, which can be 'compensated' by the intake of different psychoactive drugs. Hence, animals showing propensity for developing dependence to a specific drug class may also be useful for modeling other addictions. We compared the effects of repeated (14 daily doses) morphine (10 mg/kg) or methadone (2 mg/kg) treatment followed by a 2-week withdrawal and a morphine challenge (5 mg/kg) on locomotor activity, brain Fos expression and selected brain regional levels of dopamine, serotonin and their metabolites in the 38th generations of selectively bred Warsaw low-alcohol-preferring (WLP) and Warsaw high-alcohol-preferring (WHP) rat lines. The rats were given the opioids during the active (i.e. dark) phase of their daily cycle. Drug-naïve WHP rats compared to their WLP counterparts showed higher locomotor activity in an open field test and higher propensity for lasting behavioral sensitization to morphine. Morphine did not significantly enhance, but suppressed Fos expression in certain brain regions of drug-naïve WLP and WHP rats. Fos expression revealed considerable differences in the responses of WLP and WHP rats to morphine challenge, particularly after methadone pretreatment. These differences were associated with differences in monoamine metabolite levels that were suggestive of elevated basal ganglia and lowered frontal cortical dopamine function, and of lowered somatosensory cortex serotonin function, in the morphine-challenged WHP rats (irrespective of the pretreatment type). Hence, the WLP/WHP line pair may be useful for the search of factors that underlie the propensity for developing opiate dependence.
authors.affiliation: Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego St., 02-957 Warsaw, Poland. taracha@ipin.edu.pl
authors.forename: Ewa
authors.initials: E
authors.lastname: Taracha
authors.forename: Wanda
authors.initials: W
authors.lastname: Dyr
authors.forename: Marta
authors.initials: M
authors.lastname: Ćwiek
authors.forename: Danuta
authors.initials: D
authors.lastname: Turzyńska
authors.forename: Jerzy
authors.initials: J
authors.lastname: Walkowiak
authors.forename: Edyta
authors.initials: E
authors.lastname: Wyszogrodzka
authors.forename: Wojciech
authors.initials: W
authors.lastname: Kostowski
authors.forename: Adam
authors.initials: A
authors.lastname: Płaźnik
authors.forename: Stanisław J
authors.initials: SJ
authors.lastname: Chrapusta
mesh_terms: D000428:Alcohol Drinking / Q000378:metabolism*; D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D015306:Biogenic Monoamines / Q000378:metabolism*; D001921:Brain / Q000187:drug effects; D004195:Disease Models, Animal; D004298:Dopamine / Q000502:physiology; D008297:Male; D008691:Methadone / Q000494:pharmacology; D009020:Morphine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D009293:Opioid-Related Disorders / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D012701:Serotonin / Q000502:physiology
chemical_list: D000701:Analgesics, Opioid; D015306:Biogenic Monoamines; D016760:Proto-Oncogene Proteins c-fos; D012701:Serotonin; D009020:Morphine; D008691:Methadone; D004298:Dopamine