Ed J. M. Pennings

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Rationale: (±) 3,4-Methylenedioxymethamphetamine (MDMA or "ecstasy") has been shown to cause long term damage to serotonergic cerebral neurons in animals. The neurotoxic effects in humans are less clear and little is known about the functional consequences, although some studies suggest memory impairment. Given the widespread use of MDMA, our lack of(More)
An assay is described for the enzyme tryptophan decarboxylase from plant cell suspension cultures. It is based on the fluorometric detection of tryptamine by HPLC on a LiChrosorb RP-8 Select B column. Tryptophan decarboxylase from Catharanthus roseus was induced by transferring 14-day-old cells into an induction medium. Optimum activity was found 2 days(More)
An HPLC assay is described for the enzyme strictosidine synthase in which the formation of strictosidine and the decrease of tryptamine can be followed at the same time. In cell cultures of Catharanthus roseus significant amounts of strictosidine glucosidase activity were detected. In crude preparations, the strictosidine synthase reaction is therefore best(More)
The enzyme tryptophan decarboxylase (TDC) (EC catalyses a key step in the biosynthesis of terpenoid indole alkaloids inC. roseus by converting tryptophan into tryptamine. Hardly anytdc mRNA could be detected in hormone-independent callus and cell suspension cultures transformed by the oncogenic T-DNA ofAgrobacterium tumefaciens. Supply of(More)
To investigate systemic serotonin (5-HT) metabolism in migraine, we determined platelet and platelet-free plasma concentrations of 5-HT, its precursors tryptophan and 5-hydroxytryptophan, and its main metabolite 5-hydroxyindoleacetic acid (5-HIAA), as well as the activities of the platelet enzymes monoamine oxidase and phenolsulfotransferase in classic and(More)
In preparing a decision about the legal status of khat in the Netherlands, the Dutch Minister of Health requested CAM (Coordination point Assessment and Monitoring new drugs) to assess the overall risk of khat in the Netherlands. The present paper is a redraft of a report which formed the scientific basis of the risk evaluation procedure (October 2007).(More)
The combination of alcohol and cocaine is popular among drug users, perhaps because of more intense feelings of 'high' beyond that perceived with either drug alone, less intense feelings of alcohol-induced inebriation and tempering of discomfort when coming down from a cocaine 'high'. A review is presented of the medical literature on psychological and(More)
UNLABELLED We previously reported that a single dose of the serotonin receptor agonist meta-chlorophenylpiperazine increased the peak velocity of saccadic eye movements and decreased low-frequency electroencephalographic activity. METHODS We administered a single dose of the serotonin releaser dexfenfluramine in a double blind, placebo controlled(More)
Some properties of rat brain phenol sulphotransferase were investigated in in vitro at pH7.4. The enzyme was purified 10-fold by chromatography on DEAE-Sephadex -50. It can be assayed with 4-hydroxy-3-methoxyphenylethylene glycol or 4-methylumbelliferone as the sulphate acceptor. The partially purified enzyme is stable for at least 1 week when stored at 4(More)