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Repeated administration of high doses of methamphetamine produced long-term decreases in dopamine (DA) levels and in the number of DA uptake sites in the rat striatum. These two effects were dose-related and did not appear to be due to the continued presence of drug in striatal tissue. Long-lasting depletions induced by methamphetamine were selective for(More)
The discriminative stimulus (DS) effects of smoked marijuana were studied by training marijuana smokers to discriminate between the effects of marijuana containing 2.7% delta 9-THC (M) and marijuana containing 0.0% delta 9-THC (P). In addition to measures of discrimination responding, subjective effects were assessed with standardized mood questionnaires.(More)
Repeated administration of large doses of d-methamphetamine produce long-lasting depletion of brain dopamine (DA) and serotonin (5-HT), as well as persistent decreases in the activity of their respective biosynthetic enzymes, tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH). The present results indicate that the inhibitor of 5-HT uptake(More)
Repeated administration of methamphetamine was found to cause long-term changes in caudate dopamine levels in the rat and guinea pig. Methamphetamine was administered twice a day for thirty days. Two weeks following the last injection, the animals were killed and brains assayed for catecholamine content. These long-term depletions of dopamine, when combined(More)
The effects of cocaine (4.0--32 mg/kg) on schedule-controlled behavior of rats were determined before and during a period of repeated administration of cocaine. In rats trained to lever press on a fixed ratio 40 schedule for food delivery, cocaine (8.0--32 mg/kg) initially decreased response rate in a dose-related manner. During the period of repeated(More)
The origin of Galactic cosmic rays (with energies up to 10 15 eV) remains unclear, though it is widely believed that they originate in the shock waves of expanding supernova remnants [1][2]. Currently the best way to investigate their acceleration and propagation is by observing the γ-rays produced when cosmic rays interact with interstellar gas [3]. Here(More)
A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and(More)
(Received September 1, 1975) : d-Amphetamine, methamphetamine and other phenethylamines cause decreases in food intake, stereotypic behavior, disruption of behavior that is under stimulus control, as well as general sympathomimetic effects such as hyperthermia, increased blood pressure and piloerection. The doses required to produce different effects vary.(More)
Methamphetamine and amphetamine were continuously administered to rats for 3 days by means of subcutaneously implanted osmotic minipumps. The total daily dose of each drug was approximately 4 mg/day. Dopamine, norepinephrine and serotonin determinations two weeks later indicated that both amphetamines produced a selective striatal dopamine depletion.(More)