Synthetic cannabinoid 5F-AMB reduced anxiety and impaired memory in mice through CB1 receptors | Research

The takeaway

The synthetic cannabinoid 5F-AMB produced anxiety-reducing effects and impaired memory acquisition through CB1 receptor activation in mice, with the prefrontal cortex involved in memory impairment but not the anxiety effect.

People interested in synthetic cannabinoid effects, neuroscience of cannabis-related memory impairment, and substance safety.

5F-AMB impaired memory via prefrontal cortex but reduced anxiety via other brain regions

What the researchers found

Central 5F-AMB produced anxiolytic effects and impaired recognition memory acquisition via CB1 receptors (blocked by AM251). Systemic 5F-AMB severely reduced locomotor activity. Direct prefrontal cortex infusion impaired memory but did not reduce anxiety, suggesting different brain regions mediate each effect.

Why it matters

Synthetic cannabinoids like 5F-AMB are increasingly found in illegal products, yet their specific effects on brain function are largely unknown. This study maps which brain functions they affect and through which mechanisms.

The numbers in context

5F-AMB 0.3 mg/kg IP dramatically decreased locomotor activity (partially reversed by AM251 3 mg/kg). ICV 5F-AMB 10 nmol: anxiolytic + memory impairment (both blocked by AM251). Intra-mPFC 5F-AMB: impaired memory only, not anxiety.

How the study worked

Behavioral pharmacology in C57BL/6J mice using intraperitoneal, intracerebroventricular, and intra-prefrontal cortex administration of 5F-AMB with the CB1 antagonist AM251. Assessed via open field test (anxiety, locomotion) and novel object recognition test (memory).

What this study cannot tell us

Mouse model with direct brain injection for mechanistic studies. Single synthetic cannabinoid studied. Acute effects only. The severe locomotor effect of systemic administration complicates interpretation of other behavioral measures.

How to read the evidence

Preliminary: systematic animal pharmacology study with appropriate controls and brain region dissection.

When this study was published

Published in 2019.

The bigger picture

The dissociation between anxiety and memory effects in specific brain regions suggests that synthetic cannabinoid effects are not monolithic. The severe locomotor impairment at systemic doses is particularly concerning for user safety.

Questions still open

Which brain regions mediate the anxiolytic effect if not the prefrontal cortex? Would chronic exposure produce tolerance to the locomotor effects? How does 5F-AMB compare to THC in these behavioral assays?

Common questions

What does 5F-AMB do to the brain?

In mice, it reduced anxiety and impaired the ability to form new memories, both through CB1 receptors. Notably, the prefrontal cortex was involved in memory impairment but not the anxiety reduction, suggesting different brain circuits.

Is 5F-AMB dangerous?

The study found systemic 5F-AMB dramatically reduced locomotor activity in mice, suggesting severe impairment at doses that might be used recreationally. Human reports include impaired memory and disturbed consciousness.

Read the original research

Effects of the synthetic cannabinoid 5F-AMB on anxiety and recognition memory in mice.

Psychopharmacology, 236(7), 2235-2242

View on PubMed ↗Publisher’s paper ↗

Citation

Ito, Shiho; Deyama, Satoshi; Domoto, Masaki; Zhang, Tong; Sasase, Hitoki; Fukao, Akari; Esaki, Hirohito; Hinoi, Eiichi; Kaneko, Shuji; Kaneda, Katsuyuki. (2019). Effects of the synthetic cannabinoid 5F-AMB on anxiety and recognition memory in mice.. Psychopharmacology, 236(7), 2235-2242. https://doi.org/10.1007/s00213-019-05222-2