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Effects of methylenedioxymethamphetamine on local cerebral glucose utilization in the rat
1Neuropharmacology Laboratory, National Institute on Drug Abuse, Baltimore, Maryland 21224.
Abstract:
The effects of (+-)3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") (5, 10, 15 or 30 mg/kg, i.p.) on local cerebral utilization of glucose were studied by the quantitative autoradiographic 2-deoxy-D-[1-14C]glucose method in awake adult male Fischer-344 rats. Statistically significant effects on local utilization of glucose, 5 min after the administration of MDMA were observed in 20 of 60 areas of brain sampled. Marked stimulation was seen in components of the extrapyramidal motor system (substantia nigra, globus pallidus, entopenduncular nucleus, subthalamic nucleus, cerebellar vermis). The limbic system showed decrements in the medial cortex and hippocampal dentate gyrus (outer blade) and the lateral habenula, while there was stimulation in the mammillary body and the basolateral amygdaloid nucleus. Glucose utilization in MDMA-treated rats was reduced in the superior colliculus and medial terminal nucleus of the accessory optic system, but was unchanged in the visual cortex and components of the auditory system. Some of the effects of MDMA on cerebral utilization of glucose resembled those previously reported with l-cocaine, d-amphetamine, and phencyclidine, implicating some common mechanisms in the actions of these drugs.
Insights
3,4-methylenedioxymethamphetamine (MDMA) significantly altered glucose utilization in 20 of 60 rat brain areas. Effects varied by region, impacting motor, limbic, and visual systems, suggesting common drug action mechanisms.
Area of Science:
- Neuroscience
- Pharmacology
Background:
- 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") is a psychoactive drug with known neurological effects.
- Understanding MDMA's impact on brain metabolism is crucial for elucidating its mechanisms of action.
Purpose of the Study:
- To investigate the effects of varying doses of MDMA on local cerebral glucose utilization in rats.
- To identify specific brain regions affected by MDMA administration.
Main Methods:
- Quantitative autoradiographic 2-deoxy-D-[1-14C]glucose method was employed.
- Experiments were conducted in awake adult male Fischer-344 rats.
- MDMA was administered intraperitoneally at doses of 5, 10, 15, or 30 mg/kg.
Main Results:
- MDMA administration (5 min post-injection) significantly altered glucose utilization in 20 out of 60 sampled brain areas.
- Stimulation of glucose metabolism was observed in the extrapyramidal motor system (e.g., substantia nigra, globus pallidus) and parts of the limbic system (e.g., mammillary body, basolateral amygdaloid nucleus).
- Decreased glucose utilization was noted in the limbic system (medial cortex, hippocampal dentate gyrus) and visual pathways (superior colliculus, medial terminal nucleus of the accessory optic system).
Conclusions:
- MDMA exerts region-specific effects on cerebral glucose utilization in rats.
- Observed metabolic changes in motor, limbic, and visual systems suggest complex neurochemical interactions.
- The findings indicate potential shared mechanisms of action between MDMA and other psychostimulants like cocaine, amphetamine, and phencyclidine.