Effects of Long-Term Ayahuasca Administration on Memory and Anxiety in Rats
PLoS ONE – December 30, 2015
Source: OpenAlex
Summary
Long-term administration of ayahuasca, a hallucinogenic beverage, significantly enhances contextual fear responses in rats. In a study involving 30 days of daily doses (120, 240, and 480 mg/kg), the 120 mg/kg dose notably increased contextual conditioned fear responses, while performance on tasks like the Morris water maze and elevated plus maze remained unaffected. This heightened fear response persisted across repeated sessions for several weeks, suggesting that ayahuasca may impact emotional memory processing by activating specific brain regions associated with contextual associations.
Abstract
Ayahuasca is a hallucinogenic beverage that combines the action of the 5-HT2A/2C agonist N,N-dimethyltryptamine (DMT) from Psychotria viridis with the monoamine oxidase inhibitors (MAOIs) induced by beta-carbonyls from Banisteriopsis caapi. Previous investigations have highlighted the involvement of ayahuasca with the activation of brain regions known to be involved with episodic memory, contextual associations and emotional processing after ayahuasca ingestion. Moreover long term users show better performance in neuropsychological tests when tested in off-drug condition. This study evaluated the effects of long-term administration of ayahuasca on Morris water maze (MWM), fear conditioning and elevated plus maze (EPM) performance in rats. Behavior tests started 48h after the end of treatment. Freeze-dried ayahuasca doses of 120, 240 and 480 mg/kg were used, with water as the control. Long-term administration consisted of a daily oral dose for 30 days by gavage. The behavioral data indicated that long-term ayahuasca administration did not affect the performance of animals in MWM and EPM tasks. However the dose of 120 mg/kg increased the contextual conditioned fear response for both background and foreground fear conditioning. The tone conditioned response was not affected after long-term administration. In addition, the increase in the contextual fear response was maintained during the repeated sessions several weeks after training. Taken together, these data showed that long-term ayahuasca administration in rats can interfere with the contextual association of emotional events, which is in agreement with the fact that the beverage activates brain areas related to these processes.