Effects of footshock stress on regional brain monoamine metabolism and the acquisition of conditioned freezing in rats previously exposed to repeated methamphetamine.
1. Effects of footshock stress on regional brain DA and 5-HT metabolism and the acquisition of conditioned fear in male Wistar-King rats previously exposed to repeated MA were examined. 2. MA-pretreated rats exhibited more freezing than control rats in the conditioned fear test. 3. The HVA levels in the striatum was elevated by footshock only in MA-treated rats but not saline-treated rats. Furthermore, MA-treated rats showed increased metabolism of DA in the mPFC, even when placed in the shock chamber without shocks. 4. The brain serotonergic responsiveness to fear conditioning was also attenuated by repeated administration of MA. 5. These results suggest that not only the brain DA systems but also the brain 5-HT systems play an important role for the development of MA-induced emotional hypersensitivity to stress.
Tsuchiya
K
K
Department of Psychiatry, Hokkaido University School of Medicine, Sapporo, Japan.
Inoue
T
T
Izumi
T
T
Hashimoto
S
S
Koyama
T
T
D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D001923:Brain Chemistry / Q000187:drug effects*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004597:Electroshock; D005239:Fear / Q000187:drug effects; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism; D013315:Stress, Psychological / Q000378:metabolism* / Q000523:psychology
D015306:Biogenic Monoamines; D000697:Central Nervous System Stimulants; D012701:Serotonin; D008694:Methamphetamine; D004298:Dopamine