Enhanced morphine- and cocaine-induced behavioral sensitization in alcohol-preferring AA rats.
Locomotor stimulation and behavioral sensitization induced by acute and repeated treatment with alcohol, cocaine or morphine were studied in the alcohol-preferring AA (Alko, Alcohol), alcohol-avoiding ANA (Alko, Non-Alcohol) rats and non-selected Wistar rats. Daily treatment with alcohol (ethanol, 0.4 or 1.0 g/kg, IP) for 6 days had no effect on locomotor activity either in the AA or ANA rats. Acute cocaine (5, 10 or 20 mg/kg, IP) produced a locomotor stimulation in the animals of all lines studied, and there was no difference in this effect between the AA and ANA rats. During a 4-day repeated cocaine treatment, the AA rats became sensitized with the 10 mg/kg dose, while the ANA rats did not show any sensitization with this dose. With the 20 mg/kg cocaine dose, in addition to locomotor stimulation, the rats of all lines studied showed stereotyped behavior, which response was enhanced during repeated treatment. Morphine-induced locomotor stimulation was larger in the AA rats than in the ANA or Wistar rats both with 1.0 and 3.0 mg/kg doses and only the AA rats were sensitized during 4-day treatment with the 1 mg/kg dose. With the 3.0 mg/kg morphine dose, only the AA rats showed a weak sensitization evident only during the initial 30 min after morphine injection. As the drug-induced behavioral sensitization is an important factor in the development of drug addiction, it is possible that mechanisms underlying the enhanced susceptibility of the AA rats to morphine- and cocaine-induced sensitization contribute to the high intake of alcohol and other abused drugs by these animals.
Honkanen
A
A
University of Turku, PreFa/Preclinical Pharmacology Research Unit, Finland. aapo.honkanen@utu.fi
Mikkola
J
J
Korpi
E R
ER
Hyytiä
P
P
Seppälä
T
T
Ahtee
L
L
D000428:Alcohol Drinking / Q000523:psychology; D000438:Alcohols / Q000494:pharmacology*; D000701:Analgesics, Opioid / Q000097:blood / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004777:Environment; D008297:Male; D009020:Morphine / Q000097:blood / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000494:pharmacology
D000438:Alcohols; D000701:Analgesics, Opioid; D018765:Dopamine Uptake Inhibitors; D012965:Sodium Chloride; D009020:Morphine; D003042:Cocaine