Administration Of D-amphetamine Sulfate Research Articles

The effects of pH on amphetamine-induced dopamine release as measured by [formula omitted] dialysis

The release of endogenous dopamine (DA) from the rat corpus striatum before and after the administration of d-amphetamine sulphate (AMPH) was monitored by in vivo dialysis to compare the effects of perfusion media at pH 6.0 and at pH 7.4. Basal release of DA did not differ significantly at pH 6.0 (61.25 ± 5.34 pg/sample, n = 4) or pH 7.4 (58.02 ± 14.17 pg/sample, n = 4). The basal value of homovanillic acid (HVA) was not significantly reduced at pH 7.4 as compared with pH 6.0; while there was a significant reduction in 3, 4-dihydroxyphenylacetic acid (DOPAC) at pH 7.4 as compared to pH 6.0. Intraperitoneal injection of 2.5 mg/kg AMPH resulted in a 21 fold increase in the concentration of DA appearing in subsequent dialysis samples. This increase in DA release was not significantly affected by the pH. Equally the decrease in DOPAC and HVA content following AMPH were also not altered by the pH. These present results differ from experiments using push-pull cannulae and suggest that responses observed with the two techniques may not be equivalent.

Chronic administration of D-amphetamine increases [ 3H]spiroperidol binding in cat brain

Administration of D-amphetamine sulfate twice daily for 10 consecutive days, in doses increasing from 10 mg/kg per day (i.p.) to 30 mg/kg per day resulted in significant increases in the B max for [ 3H]spiroperidol receptor binding in the striatum (+44.7%) and limbic forebrain (+40.3%) in cats. There were no significant changes in the K D value for either brain region. A single dose of amphetamine (15 mg/kg i.p.) produced no significant changes in [ 3H]spiroperidol binding in either brain region. These data are in contrast with previous studies which reported a significant decrease in dopamine receptor binding following chronic amphetamine treatment in rats.

Cats develop tolerance to d-amphetamine's effects upon locomotion and stereotyped behaviors

Administration of d-amphetamine sulfate (7.5 mg/kg i.p.) twice daily to cats produces an initial large increase in both locomotion and behavioral stereotypy. As this regimen continues beyond three days, however, both measures show large significant decreases. We hypothesize that this tolerance to the behavioral effects of amphetamine is attributable to the concomitant decrease (approx. 70%) in presynaptic stores of dopamine and norepinephrine.

Recovery of Amnestic Effect of α-Amanitin by Post-Training Administration of <i>d</i>-Amphetamine in the Rat

alpha-Amanitin, an inhibitor of RNA polymerase II, given intraventricularly 6 or 24 h before training, impaired consolidation of both passive and active avoidance responses in rats. Administration of d-amphetamine sulfate (0.5 mg/kg intraperitoneally) immediately after training produced a clear-cut antiamnestic effect in alpha-amanitin-injected rats without modifying consolidation in control animals. Examination of several parameters of conditioning enabled the authors to rule out an impairment in locomotor performance of alpha-amanitin-treated rats both in training and in test sessions. The amnestic effect of alpha-amanitin and recovery by means of d-amphetamine were discussed in relation to RNA synthesis inhibition and a possible restoring effect of d-amphetamine upon alpha-amanitin-induced decrease of brain RNA content.

Olfactory bulb removal results in elevated spontaneous locomotor activity in mice

Bilateral removal of the olfactory bulbs of female Swiss-Webster mice resulted in a striking increase in locomotor activity which remained evident even 2 1 2 months after surgery. The administration of d-amphetamine sulfate (1, 2, and 4 mg/kg) resulted in a dose dependent increase in locomotor activity but bilateral bulbectomy did not potentiate amphetamine's motor stimulant effect. The neural processes which mediate bulbectomy induced hyperactivity in the mouse are not known; however, it is clear that these processes, unlike processes involved in some other lesions which produce hyperactivity, do not interact with the locomotor facilitatory property of d-amphetamine. D-amphetamine sulfate (1, 2, and 4 mg/kg) caused a dose dependent decrease in food intake but there was no interaction between bulbectomy and the anorexic activity of d-amphetamine. The fact that bulbectomized mice display elevated locomotor activity in a nonsocial situation suggests an effect of bulbectomy upon arousal. From this perspective it is possible that many of the previously discovered social behavioral deficits produced by bulbectomy are specific manifestations of altered arousal processes.

Effect of amphetamine and fenfluramine on brain noradrenaline and MOPEG-SO 4

I.p. administration of d-amphetamine sulphate and fenfluramine · HCl at various doses induced significant modifications of brain noradrenaline (NA) and MOPEG-SO 4 (3-methoxy-4-hydrorxyphenylethyleneglycol) in the rat. Both drugs induced a decrease in brain noradrenaline but the two compounds seem to interact with the central noradrenergic system through a different mechanism. The decreased levels of noradrenaline after 1-fenfluramine administration were paralleled by increased MOPEG-SO 4 levels. The d-isomer of fenfluramine was less active than the l-isomer. Amphetamine was considerably more effective than 1-fenfluramine in reducing NA concentration. However, in spite of the long lasting effect on noradrenaline levels the i.p. administration of amphetamine did not lead to an increased MOPEG-SO 4 concentrations suggesting a more complex interaction with the noradrenergic system.

Further Support for a Placebo Effect in the Rat

The effects of prior administration of d-Amphetamine sulfate on activity of the rat were studied. The results confirm a placebo effect.