Premedication and general anesthetic agents decrease plasma concentration of the endocannabinoid anandamide in dogs

Area of Science:

• Veterinary Anesthesiology
• Neuroendocrinology
• Cannabinoid Research

Background:

• The endocannabinoid system plays a role in pain modulation and neuroprotection.
• Anandamide (AEA) is a key endocannabinoid with potential implications during anesthesia.
• Understanding AEA changes during general anesthesia (GA) in dogs is crucial for optimizing patient care.

Purpose of the Study:

• To investigate the impact of isoflurane (ISO) versus sevoflurane (SEVO) general anesthesia on plasma AEA concentrations in dogs.
• To determine if GA duration, fluid administration, or concurrent medications affect AEA levels.
• To explore the relationship between premedication, GA, and endocannabinoid signaling in canine patients.

Main Methods:

• Analysis of plasma samples from 21 dogs undergoing GA, randomized to ISO or SEVO.
• Measurement of plasma AEA concentrations using High-Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MS-MS).
• Statistical analysis including linear mixed models to assess effects of anesthetic type, duration, fluid volume, and other treatments.

Main Results:

• Plasma AEA concentrations significantly decreased post-GA in both ISO and SEVO groups.
• Mean AEA levels dropped from approximately 29 ng/mL to 12.3 ng/mL (ISO) and 26.6 ng/mL to 11.1 ng/mL (SEVO).
• No significant differences in AEA reduction were found between anesthetic groups or correlated with anesthesia duration, fluid volume, surgery type, or NSAID/steroid use.

Conclusions:

• General anesthesia significantly reduces plasma AEA concentrations in dogs, irrespective of the inhalant anesthetic used (ISO or SEVO).
• The observed reduction in AEA may be influenced by other concurrently administered anesthetic agents.
• This study is the first to suggest an interaction between anesthesia protocols and endocannabinoid signaling in dogs.