Endocannabinoid Signaling and the Hypothalamic-Pituitary-Adrenal Axis.

“The elucidation of Δ9-tetrahydrocannabinol as the active principal of Cannabis sativa in 1963 initiated a fruitful half-century of scientific discovery, culminating in the identification of the endocannabinoid signaling system, a previously unknown neuromodulatory system. A primary function of the endocannabinoid signaling system is to maintain or recover homeostasis following psychological and physiological threats. We provide a brief introduction to the endocannabinoid signaling system and its role in synaptic plasticity. The majority of the article is devoted to a summary of current knowledge regarding the role of endocannabinoid signaling as both a regulator of endocrine responses to stress and as an effector of glucocorticoid and corticotrophin-releasing hormone signaling in the brain. We summarize data demonstrating that cannabinoid receptor 1 (CB1R) signaling can both inhibit and potentiate the activation of the hypothalamic-pituitary-adrenal axis by stress. We present a hypothesis that the inhibitory arm has high endocannabinoid tone and also serves to enhance recovery to baseline following stress, while the potentiating arm is not tonically active but can be activated by exogenous agonists. We discuss recent findings that corticotropin-releasing hormone in the amygdala enables hypothalamic-pituitary-adrenal axis activation via an increase in the catabolism of the endocannabinoid N-arachidonylethanolamine. We review data supporting the hypotheses that CB1R activation is required for many glucocorticoid effects, particularly feedback inhibition of hypothalamic-pituitary-adrenal axis activation, and that glucocorticoids mobilize the endocannabinoid 2-arachidonoylglycerol. These features of endocannabinoid signaling make it a tantalizing therapeutic target for treatment of stress-related disorders but to date, this promise is largely unrealized.” https://www.ncbi.nlm.nih.gov/pubmed/28134998]]>

Topical application of THC containing products is not able to cause positive cannabinoid finding in blood or urine.

“A male driver was checked during a traffic stop. A blood sample was collected 35min later and contained 7.3ng/mL THC, 3.5ng/mL 11-hydroxy-THC and 44.6ng/mL 11-nor-9-carboxy-THC. The subject claimed to have used two commercially produced products topically that contained 1.7ng and 102ng THC per mg, respectively. In an experiment, three volunteers (25, 26 and 34 years) applied both types of salves over a period of 3days every 2-4h. The application was extensive (50-100cm2). Each volunteer applied the products to different parts of the body (neck, arm/leg and trunk, respectively). After the first application blood and urine samples of the participants were taken every 2-4h until 15h after the last application (overall n=10 urine and n=10 blood samples, respectively, for each participant). All of these blood and urine samples were tested negative for THC, 11-hydroxy-THC and 11-nor-9-carboxy-THC by a GC-MS method (LoD (THC)=0.40ng/mL; LoD (11-hydroxy-THC)=0.28ng/mL; LoD (THC-COOH)=1.6ng/mL;. LoD (THC-COOH in urine)=1.2ng/mL). According to our studies and further literature research on in vitro testing of transdermal uptake of THC, the exclusive application of (these two) topically applied products did not produce cannabinoid findings in blood or urine.” https://www.ncbi.nlm.nih.gov/pubmed/28122323]]>

Molecular Pharmacology of Phytocannabinoids.

Related image “Cannabis sativa has been used for recreational, therapeutic and other uses for thousands of years. The plant contains more than 120 C21 terpenophenolic constituents named phytocannabinoids. The Δ9-tetrahydrocannabinol type class of phytocannabinoids comprises the largest proportion of the phytocannabinoid content. Δ9-tetrahydrocannabinol was first discovered in 1971. This led to the discovery of the endocannabinoid system in mammals, including the cannabinoid receptors CB1 and CB2. Δ9-Tetrahydrocannabinol exerts its well-known psychotropic effects through the CB1 receptor but this effect of Δ9-tetrahydrocannabinol has limited the use of cannabis medicinally, despite the therapeutic benefits of this phytocannabinoid. This has driven research into other targets outside the endocannabinoid system and has also driven research into the other non-psychotropic phytocannabinoids present in cannabis. This chapter presents an overview of the molecular pharmacology of the seven most thoroughly investigated phytocannabinoids, namely Δ9-tetrahydrocannabinol, Δ9-tetrahydrocannabivarin, cannabinol, cannabidiol, cannabidivarin, cannabigerol, and cannabichromene. The targets of these phytocannabinoids are defined both within the endocannabinoid system and beyond. The pharmacological effect of each individual phytocannabinoid is important in the overall therapeutic and recreational effect of cannabis and slight structural differences can elicit diverse and competing physiological effects. The proportion of each phytocannabinoid can be influenced by various factors such as growing conditions and extraction methods. It is therefore important to investigate the pharmacology of these seven phytocannabinoids further, and characterise the large number of other phytocannabinoids in order to better understand their contributions to the therapeutic and recreational effects claimed for the whole cannabis plant and its extracts.” https://www.ncbi.nlm.nih.gov/pubmed/28120231
]]>