Erowid References Database
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Waldmeier PC, Maître L.
“Neurochemical Investigations of the Interaction of N,N-Dimethyltryptamine with the Dopaminergic System in Rat Brain”.
Psychopharmacology. 1977;52(2):137-44.
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Abstract
The neurochemical effects of N,N-dimethyltryptamine (DMT) on the dopaminergic system of the rat brain, were investigated. MAO activity was determined in whole brain or corpus striatum of female Sprague-Dawley rats (i40-200 g) by radio assay using 14C-5XT, 3H-dopamine (DA) or 14C-phenylethylamine (Pt) as substrate. Male rats were injected with 3H-dopa after drug treatment and the brains removed 30 min later and 3H-DA and 3H-3-methoxy-tryramine (3H-MT) isolated and determined. Endogenous homovanillic acid (HVA) and DOPAC were isolated from the corpus striatum and estimated fluorometrically. Rats were s.c. pretreated with 10 mg/kg d-amphetamine (AM; Siegfried) before 3H-dopa and the striate removed 30 min later and 3H-HVA estimated. DMT (50 mg/kg; i.p.; CIBA-Geigy) inhibited MAO, but had less effect on the deamination of PE than on 5-HT or DA. There was no difference between whole brain and striatum and both 5-HT and DA had identical dose response curves with an ED50 of 25 mg/kg. Neither d-AM or i.p. apomorphine (APO; Siegfried; 20 mg/kg) inhibited MAO. 30 mg/kg DMT caused a 600 0ncrease in 3H-DA + 3H-MT fraction when given 15 min before dope, but had little effect on the 3H-NA + 3H-MT fraction. As the pretreatment period increased, the effect on the DA+MT fraction declined. The effect of DMT was dose related; maximal (35 fold increase) at 50 mg/kg. AM had a similar but less marked effect. Pargyline (50 mg/kg s.c.), - clorgyline (10 mg/kg; s.c.; both CA-Geigy) and tranylcypromine (10 mg/kg, s.c.) but not Deprenil (10 mg/kg; CIBA-Geigy) caused large increases in 3H-DA + 3H-MT. APO (20 nmcg/kg i.l?.), clonidine (CIBA-Geigy; 1 mg/kg p.o.) and tryptamine (100 mg/kg i.p.) slightly increased both 3H-DA + 3H-MT and 3H-NA + 3H-NM] fractions. FLA -63 (25 mg/kg; i.p.; Lab-Kemie) lowered 3H-NA -3H-NMN and increased 3H-DA + M-MT. Mescaline, (Fluke) LSD (Sandoz) and N-methyltryptamine (Fluke) were inactive. The proportion of 3H-DA in the fraction fell from 46 0n controls to lc after AM and 3% after DMT or tranylcypromine. DMT caused a short-lived dose related depletion of endogenous HVA and DOPA( Depletion was maximal at 1 hr and recovery was complete at 4 h AM lowered DOPAC after 30 min but not HVA levels which then increased between 1-2 hr. APO lowered both metabolite levels but HVA depletion was the longer lasting. The only metabolite isolated from the striate of rats given AM before H-dopa, was 3 HVA.
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