My gut feeling is they are monitoring CB1, CB2 receptors etc Found extensively in the gut. Some of these receptors seem to migrate to the brain when "problems" arise
“With Anavex drug candidates targeting the sigma-1 receptor, and with the mechanism of action being further validated, we are even more encouraged to advance our studies with additional neurodegenerative diseases,” said Christopher U. Missling, PhD, President and Chief Executive Officer of Anavex. “The Company is intrigued to realize the direct link to the body’s endocannabinoid system and to proceed with potential studies with our sigma-1 drugs candidates and cannabinoids.”