Combining a serotonin 5-HT2A blocker with a CB1 receptor blocker improved prepulse inhibition (a brain function disrupted in schizophrenia) more than either drug alone in mice.
Psychopharmacology researchers, schizophrenia drug developers, and neuroscientists.
Volinanserin + rimonabant combination improved PPI; neither cannabinoid drug alone did
What the researchers found
Neither the CB1 agonist WIN 55,212-2 nor the CB1 inverse agonist rimonabant alone affected prepulse inhibition (PPI) or blocked MK-801-induced PPI deficits. However, combining the 5-HT2A antagonist volinanserin with rimonabant significantly improved PPI in both normal and MK-801-treated mice, suggesting a synergistic interaction between serotonin and cannabinoid systems.
Why it matters
Current antipsychotic medications have significant side effects. Finding that combined serotonin-cannabinoid modulation works better than either alone opens a new avenue for drug combination strategies in psychotic disorders.
The numbers in context
Volinanserin + rimonabant combination increased PPI in both control and MK-801-treated mice; neither cannabinoid drug alone affected PPI.
How the study worked
Animal study in male Swiss mice testing combinations of cannabinoid drugs (WIN 55,212-2, rimonabant) and serotonin drugs (8-OH-DPAT, volinanserin) in an MK-801-induced PPI disruption model relevant to schizophrenia.
What this study cannot tell us
Animal model; MK-801-induced PPI disruption is only one aspect of schizophrenia pathology; rimonabant has been withdrawn from clinical use due to psychiatric side effects; only male mice used.
How to read the evidence
Preliminary: animal behavioral pharmacology study with synthetic compounds.
When this study was published
Published 2020.
The bigger picture
This supports the idea that complex mental illnesses may respond better to multi-target drug approaches than single-mechanism treatments. The serotonin-endocannabinoid interaction could be particularly relevant for schizophrenia.
Questions still open
- Could newer CB1 antagonists without rimonabant side effects achieve the same synergy? Would this combination approach work in human psychosis?
Common questions
What is prepulse inhibition?
Why did the combination work but not the individual drugs?
Read the original research
Effects of combined 5-HT2A and cannabinoid receptor modulation on a schizophrenia-related prepulse inhibition deficit in mice.
Psychopharmacology, 237(6), 1643-1655
Citation
Marques, Adriana M; Macena, Michele V; Cardoso, Aline R; Hammes, Camila S O; Pinheiro, Fernanda M L; Castro, Newton G; Neves, Gilda A. (2020). Effects of combined 5-HT2A and cannabinoid receptor modulation on a schizophrenia-related prepulse inhibition deficit in mice.. Psychopharmacology, 237(6), 1643-1655. https://doi.org/10.1007/s00213-020-05485-0
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