The Endocannabinoid System
The Endocannabinoid system is a signaling pathway that occupies the brain, nervous system and is sparsely distributed throughout the rest of the body [1,2]. This system is comprised of cannabinoid 1 and 2 receptors (CB1 and CB2) that dominate the central nervous system and immune system respectively. These receptors become activated upon cannabinoid ligation, and subsequently influence a number of physiological factors such as immune responses, cardiovascular function, bone development, digestion and metabolism, as well as several other processes including wake/sleep cycles, learning, pain response, and regulation of stress and appetite [1,2,3].
Cannabinoids are chemical compounds that activate CB1 and CB2 receptors. They are grouped into three generalized categories: Endocannabinoids are endogenously found within the body, and include compounds Anandamide and 2-AG; phytocannabinoids are found in the vegetative matter of cannabis, and include the most widely known cannabinoids THC and CBD; synthetic cannabinoids are often generated chemically within a laboratory setting and includes a range of notable brands [3,4].
Cannabis and Cannabinoids
Cannabis is comprised of over 400 chemical substances, 70 of which are cannabinoids – the chemical component of the herb, found on the mature flowers of the female plant, that acts upon cannabinoid receptors (CB1 and CB2) within the body. Cannabis is found in two major subspecies: Cannabis indica and Cannabis sativa, that differ based on their cannabinoid compositions [1,6,8,13].
The principal cannabinoids existing in cannabis are Δ-9-tetrahydrocannabinol (ie. Δ9-THC, THC) and cannabidiol (CBD), however CBD does not directly stimulate either CB1 or CB1 receptors. [1,2]. THC largely acts on the CB1 receptors located in the peripheral and central nervous system, including the brain, and is therefore largely responsible for the for the major physical and psychotropic effects brought on by cannabis use [1,2]. Conversely, CBD is an indirect antagonists of CB1 and CB2 receptors, and rather serves other functions including activating several non-cannabinoid receptors including 5-HT1A serotonin receptors responsible for stimulating positive emotions; and also acts to prevents the reuptake of neurotransmitters such as anandaminde that serves important roles in generating feelings of motivation and pleasure [2,4,15].
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