Natural Variation in Brain Endocannabinoid Levels Was Linked to Resting Heart Rate in Rats
Rats with naturally higher anandamide levels and lower FAAH activity in a specific brainstem region had higher resting heart rates, and injecting anandamide into this region increased heart rate.
Quick Facts
What This Study Found
Researchers examined whether natural animal-to-animal variation in endocannabinoid signaling in the dorsal periaqueductal gray (dPAG), a brainstem region involved in autonomic control, correlated with baseline heart rate.
Higher resting heart rate was associated with increased anandamide content and decreased FAAH enzyme activity in this brain region. FAAH and MAGL gene expression levels were negatively correlated with heart rate. When anandamide was directly injected into the dPAG of anesthetized rats, heart rate increased.
Autonomic tone and heart rate (but not blood pressure) correlated with FAAH gene expression levels, suggesting that the endocannabinoid system in this specific brain region helps regulate baseline cardiovascular function.
Key Numbers
Higher anandamide content in dPAG correlated with higher heart rate. Lower FAAH activity correlated with higher heart rate. FAAH and MAGL transcript levels negatively correlated with heart rate. Exogenous anandamide in dPAG increased heart rate.
How They Did This
Blood pressure was recorded telemetrically in rats. Heart rate variability was analyzed. Endocannabinoid content, enzyme activities, and gene transcript levels were measured in the dPAG. Exogenous anandamide was injected into the dPAG of anesthetized rats to test causality.
Why This Research Matters
This study identifies a specific brain region where endocannabinoid signaling influences cardiovascular function. Understanding how the endocannabinoid system regulates heart rate has implications for understanding both the cardiovascular effects of cannabis and potential therapeutic targets.
The Bigger Picture
Cannabis use is known to increase heart rate, and this study identifies one brain mechanism through which endocannabinoids regulate cardiovascular function. The dPAG is part of the brain's autonomic control circuitry, connecting endocannabinoid signaling to the broader cardiovascular regulation system.
What This Study Doesn't Tell Us
This was an animal study using rats, and the findings may not directly translate to human cardiovascular regulation. Only the dPAG was examined; other brain regions also regulate heart rate. The correlational design (except for the injection experiment) cannot establish that endocannabinoids cause heart rate differences.
Questions This Raises
- ?Does cannabis-induced tachycardia involve this brainstem endocannabinoid mechanism?
- ?Could targeting endocannabinoid signaling in this region help manage heart rate disorders?
Trust & Context
- Key Stat:
- Higher brain anandamide levels correlated with higher resting heart rate
- Evidence Grade:
- This is an animal study combining correlational analysis with a causal intervention (anandamide injection), providing preliminary mechanistic evidence.
- Study Age:
- Published in 2016. Research on endocannabinoid regulation of cardiovascular function continues.
- Original Title:
- Components of the cannabinoid system in the dorsal periaqueductal gray are related to resting heart rate.
- Published In:
- American journal of physiology. Regulatory, integrative and comparative physiology, 311(2), R254-62 (2016)
- Authors:
- Dean, Caron, Hillard, Cecilia J(17), Seagard, Jeanne L, Hopp, Francis A, Hogan, Quinn H
- Database ID:
- RTHC-01138
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Does cannabis increase heart rate?
Yes, cannabis use is well-known to increase heart rate (tachycardia). This study identifies one brain mechanism that may contribute: endocannabinoid signaling in a brainstem region that controls autonomic cardiovascular function.
Is this why some people feel their heart racing after using cannabis?
This may be part of the explanation. THC from cannabis activates the same receptors as anandamide, and this study showed anandamide increases heart rate through a specific brainstem region. However, cannabis-induced tachycardia likely involves multiple brain and peripheral mechanisms.
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Cite This Study
https://rethinkthc.com/research/RTHC-01138APA
Dean, Caron; Hillard, Cecilia J; Seagard, Jeanne L; Hopp, Francis A; Hogan, Quinn H. (2016). Components of the cannabinoid system in the dorsal periaqueductal gray are related to resting heart rate.. American journal of physiology. Regulatory, integrative and comparative physiology, 311(2), R254-62. https://doi.org/10.1152/ajpregu.00154.2016
MLA
Dean, Caron, et al. "Components of the cannabinoid system in the dorsal periaqueductal gray are related to resting heart rate.." American journal of physiology. Regulatory, 2016. https://doi.org/10.1152/ajpregu.00154.2016
RethinkTHC
RethinkTHC Research Database. "Components of the cannabinoid system in the dorsal periaqued..." RTHC-01138. Retrieved from https://rethinkthc.com/research/dean-2016-components-of-the-cannabinoid
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.