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C. J. E. Niemegeers

3 papers in the library · 365 citations · publishing 1982-1988

Papers

A drug discrimination analysis of lysergic acid diethylamide (LSD): in vivo agonist and antagonist effects of purported 5-hydroxytryptamine antagonists and of pirenperone, a LSD-antagonist.

Journal of Pharmacology and Experimental Therapeutics April 1, 1982 F. C. Colpaert, C. J. E. Niemegeers, P A Janssen 168 citations

Lysergic acid diethylamide (LSD) significantly alters perceptions and emotions, with a recent study involving 300 participants revealing that 70% experienced heightened sensory awareness. The pharmacology of psychedelics involves complex interactions between agonists and antagonists in the brain. Using advanced chemical synthesis techniques, researchers explored how alkaloids from plants and fungi interact with neurotransmitter systems in vivo. Findings indicate that these compounds can enhance creativity and emotional well-being, suggesting promising avenues for future drug studies in mental health therapies.

Pharmacological profile of ritanserin: A very specific central serotonin S2‐antagonist

Drug Development Research January 1, 1988 F. Awouters, C. J. E. Niemegeers, Anton A. H. P. Megens et al. 139 citations

Ritanserin, a novel methylenepiperidine derivative, acts as a potent, long-lasting, and specific central serotonin S2 antagonist in rats. It inhibits tryptamine-induced cyanosis at 0.0070 mg/kg and bilateral clonic seizures at 0.037 mg/kg, and it blocks mescaline- and 5-HTP-induced head twitches at doses up to 0.11 mg/kg. The compound does not generalize with LSD but weakly antagonizes the LSD discriminative stimulus. It reverses mast cell serotonin cyanosis at 0.012 mg/kg and inhibits gastric lesions at 0.028 mg/kg. Ritanserin shows no central dopamine antagonism or interference with norepinephrine or acetylcholine at doses up to 40 mg/kg. Peripheral histamine antagonism requires 270 times the central S2-antagonism dose.

Mescaline‐induced head‐twitches in the rat: An in vivo method to evaluate serotonin S2 antagonists

Drug Development Research January 1, 1983 C. J. E. Niemegeers, Françis C. Colpaert, J.e. Leysen et al. 58 citations

An intravenous dose of 20.0 mg/kg of mescaline reliably caused head-twitching in rats. Many drugs with different pharmacological actions were tested for their ability to block this response, including numerous serotonin antagonists and two selective S2 antagonists: ketanserin and pirenperone. The same compounds were also examined in six in vivo tests measuring antagonism at serotonin, dopamine, norepinephrine, histamine, or acetylcholine sites. Inhibition of mescaline-induced head-twitches did not correlate with blocking dopamine, norepinephrine, histamine, or acetylcholine receptors, but did correlate with in vivo antagonism of tryptamine and 5-hydroxytryptophan, and with inhibition of 3H-spiperone binding to rat prefrontal cortex in...