Mice exposed to vaporized cannabis (10.3% THC) via nose-only inhalation showed decreased heart rate and blood pressure, anxiety-like behavior, and altered brain activation patterns related to sensory awareness.
Researchers studying cannabis inhalation effects, cardiovascular scientists, and those interested in animal models of drug exposure.
Peak blood THC: 136 ng/mL; heart rate and blood pressure decreased
What the researchers found
Cannabis inhalation decreased heart rate and blood pressure but promoted anxiety-like behavior in the open field test. Brain imaging (BOLD fMRI) showed cannabis increased sensory awareness while reducing behavioral arousal. Blood THC levels peaked at 136 ng/mL and increased linearly with dose.
Why it matters
This study establishes a controlled mouse model for cannabis inhalation that mimics human delivery, enabling future research on chronic cannabis use effects that would be difficult to study in humans.
The numbers in context
Cannabis contained 10.3% THC, 0.05% CBD. Particle size: 243 nm (count median diameter). Peak blood THC: 136 ng/mL. THC levels increased linearly with aerosolized mass.
How the study worked
Male adult C57BL/6 mice received nose-only exposure to vaporized cannabis (10.3% THC, 0.05% CBD). Researchers measured serum THC levels, blood pressure, heart rate, open-field behavior, and awake brain activity via BOLD fMRI.
What this study cannot tell us
Animal study using a single acute exposure in male mice only. The nose-only delivery system, while controlled, may not perfectly replicate human smoking or vaping behavior. Only one cannabis formulation was tested.
How to read the evidence
Preliminary: single acute-exposure animal study establishing a new methodology.
When this study was published
Published in 2020 in Inhalation Toxicology.
The bigger picture
The combination of cardiovascular depression and anxiety-like behavior mirrors some acute effects reported by human cannabis users, validating this animal model for future research on chronic inhalation effects.
Questions still open
- Would chronic exposure produce different cardiovascular and behavioral outcomes? How would results differ with balanced THC/CBD formulations? Would female mice show different responses?
Common questions
Why use nose-only exposure instead of a smoking chamber?
What did the brain imaging show?
Read the original research
Acute neuroradiological, behavioral, and physiological effects of nose-only exposure to vaporized cannabis in C57BL/6 mice.
Inhalation toxicology, 32(5), 200-217
Citation
Farra, Yasmeen M; Eden, Matthew J; Coleman, James R; Kulkarni, Praveen; Ferris, Craig F; Oakes, Jessica M; Bellini, Chiara. (2020). Acute neuroradiological, behavioral, and physiological effects of nose-only exposure to vaporized cannabis in C57BL/6 mice.. Inhalation toxicology, 32(5), 200-217. https://doi.org/10.1080/08958378.2020.1767237
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