Neurochemical and Behavioral Effects of a New Hallucinogenic Compound 25B-NBOMe in Rats

The hallucinogen 25B-NBOMe, which binds strongly to serotonin receptors, increased dopamine, serotonin, and glutamate release in the rat frontal cortex, striatum, and nucleus accumbens. It induced hallucinogenic activity, impaired short-term memory as measured by the novel object recognition test, and reduced locomotor activity in the open field test. In the light/dark box, rats spent more time in the dark zone, suggesting an anxiogenic effect. Scopolamine blocked the memory impairment. Unlike MDMA, 25B-NBOMe showed a subtle genotoxic effect in the comet assay. The changes in neurotransmitter levels may stem from its affinity for the 5-HT2A receptor.

Study at a glance

Abstract

Abstract 4-Bromo-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine (25B-NBOMe) is a hallucinogen exhibiting high binding affinity for 5-HT 2A/C serotonin receptors. In the present work, we investigated its effect on dopamine (DA), serotonin (5-HT), acetylcholine (ACh), and glutamate release in the rat frontal cortex, striatum, and nucleus accumbens. Hallucinogenic activity, impact on cognitive and motor functions, and anxiogenic/anxiolytic properties of this compound were also tested. The release of DA, 5-HT, ACh, and glutamate was studied using microdialysis in freely moving animals. Hallucinogenic activity was investigated using head and body twitch response (WDS), cognitive functions were examined with the novel object recognition test (NOR), locomotor activity was studied in the open field (OF), while anxiogenic/anxiolytic effect was tested using the light/dark box (LDB). Neurotoxicity was evaluated with the comet assay. 25B-NBOMe increased DA, 5-HT, and glutamate release in all studied brain regions, induced hallucinogenic activity, and lowered the recognition index ( Ri ) vs. control in the NOR test. It also decreased locomotor activity of rats in the OF test. The effect of 25B-NBOMe in the NOR test was inhibited by scopolamine. In the LDB test, the time spent in the dark zone was longer in comparison to control and was dose-dependent. In contrast to MDMA, 25B-NBOMe showed subtle genotoxic effect observed in the comet assay. Our findings indicate that 25B-NBOMe shows hallucinogenic activity in the wide range of doses. The changes in neurotransmitter levels may be related to 25B-NBOMe affinity for 5-HT 2A receptor. Alterations in the NOR, OF, and LDB indicate that 25B-NBOMe impacts short-term memory, locomotion, and may be anxiogenic.