Endocannabinoids: a unique opportunity to develop multitarget analgesics.

“After 4 millennia of more or less documented history of cannabis use, the identification of cannabinoids, and of Δ(9)-tetrahydrocannabinol in particular, occurred only during the early 1960s, and the cloning of cannabinoid CB1 and CB2 receptors, as well as the discovery of endocannabinoids and their metabolic enzymes, in the 1990s.

Despite this initial relatively slow progress of cannabinoid research, the turn of the century marked an incredible acceleration in discoveries on the “endocannabinoid signaling system,” its role in physiological and pathological conditions, and pain in particular, its pharmacological targeting with selective agonists, antagonists, and inhibitors of metabolism, and its previously unsuspected complexity.

The way researchers look at this system has thus rapidly evolved towards the idea of the “endocannabinoidome,” that is, a complex system including also several endocannabinoid-like mediators and their often redundant metabolic enzymes and “promiscuous” molecular targets.

These peculiar complications of endocannabinoid signaling have not discouraged efforts aiming at its pharmacological manipulation, which, nevertheless, now seems to require the development of multitarget drugs, or the re-visitation of naturally occurring compounds with more than one mechanism of action.

In fact, these molecules, as compared to “magic bullets,” seem to offer the advantage of modulating the “endocannabinoidome” in a safer and more therapeutically efficacious way.

This approach has provided so far promising preclinical results potentially useful for the future efficacious and safe treatment of chronic pain and inflammation.”

http://www.ncbi.nlm.nih.gov/pubmed/23623250

The endocannabinoid system, cannabinoids, and pain.

“The endocannabinoid system is involved in a host of homeostatic and physiologic functions, including modulation of pain and inflammation… Exogenous plant-based cannabinoids (phytocannabinoids) and chemically related compounds, like the terpenes, commonly found in many foods, have been found to exert significant analgesic effects in various chronic pain conditions.

Currently, the use of Δ9-tetrahydrocannabinol is limited by its psychoactive effects and predominant delivery route (smoking), as well as regulatory or legal constraints.

 However, other phytocannabinoids in combination, especially cannabidiol and β-caryophyllene, delivered by the oral route appear to be promising candidates for the treatment of chronic pain due to their high safety and low adverse effects profiles.

This review will provide the reader with the foundational basic and clinical science linking the endocannabinoid system and the phytocannabinoids with their potentially therapeutic role in the management of chronic pain.”

http://www.ncbi.nlm.nih.gov/pubmed/24228165

Endocannabinoid system and pain: an introduction.

“The endocannabinoid (EC) system consists of two main receptors: cannabinoid type 1 receptor cannabinoid receptors are found in both the central nervous system (CNS) and periphery, whereas the cannabinoid type 2 receptor cannabinoid receptor is found principally in the immune system and to a lesser extent in the CNS.

 The EC family consists of two classes of well characterised ligands; the N-acyl ethanolamines, such as N-arachidonoyl ethanolamide or anandamide (AEA), and the monoacylglycerols, such as 2-arachidonoyl glycerol. The various synthetic and catabolic pathways for these enzymes have been (with the exception of AEA synthesis) elucidated.

 To date, much work has examined the role of EC in nociceptive processing and the potential of targeting the EC system to produce analgesia.

Cannabinoid receptors and ligands are found at almost every level of the pain pathway from peripheral sites, such as peripheral nerves and immune cells, to central integration sites such as the spinal cord, and higher brain regions such as the periaqueductal grey and the rostral ventrolateral medulla associated with descending control of pain. EC have been shown to induce analgesia in preclinical models of acute nociception and chronic pain states.

 The purpose of this review is to critically evaluate the evidence for the role of EC in the pain pathway and the therapeutic potential of EC to produce analgesia. We also review the present clinical work conducted with EC, and examine whether targeting the EC system might offer a novel target for analgesics, and also potentially disease-modifying interventions for pathophysiological pain states.”

http://www.ncbi.nlm.nih.gov/pubmed/24148358

The oral administration of trans-caryophyllene attenuates acute and chronic pain in mice.

“Trans-caryophyllene is a sesquiterpene present in many medicinal plants’ essential oils, such as Ocimum gratissimum and Cannabis sativa. In this study, we evaluated the antinociceptive activity of trans-caryophyllene in murine models of acute and chronic pain and the involvement of trans-caryophyllene in the opioid and endocannabinoid systems…

 These results demonstrate that trans-caryophyllene reduced both acute and chronic pain in mice, which may be mediated through the opioid and endocannabinoid systems.”

http://www.ncbi.nlm.nih.gov/pubmed/24055516

Therapeutic potential of cannabinoid medicines.

Drug Testing and Analysis

“Cannabis was extensively used as a medicine throughout the developed world in the nineteenth century but went into decline early in the twentieth century ahead of its emergence as the most widely used illicit recreational drug later that century. Recent advances in cannabinoid pharmacology alongside the discovery of the endocannabinoid system (ECS) have re-ignited interest in cannabis-based medicines.

The ECS has emerged as an important physiological system and plausible target for new medicines. Its receptors and endogenous ligands play a vital modulatory role in diverse functions including immune response, food intake, cognition, emotion, perception, behavioural reinforcement, motor co-ordination, body temperature, wake/sleep cycle, bone formation and resorption, and various aspects of hormonal control. In disease it may act as part of the physiological response or as a component of the underlying pathology.

In the forefront of clinical research are the cannabinoids delta-9-tetrahydrocannabinol and cannabidiol, and their contrasting pharmacology will be briefly outlined. The therapeutic potential and possible risks of drugs that inhibit the ECS will also be considered. This paper will then go on to review clinical research exploring the potential of cannabinoid medicines in the following indications: symptomatic relief in multiple sclerosis, chronic neuropathic pain, intractable nausea and vomiting, loss of appetite and weight in the context of cancer or AIDS, psychosis, epilepsy, addiction, and metabolic disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/24006213

http://onlinelibrary.wiley.com/doi/10.1002/dta.1529/abstract

The use of cannabinoids in chronic pain.

“We present the case of a 56-year-old man who developed chronic pain following the excision of a facial cancer that was poorly controlled despite multiple analgesic medications. Following the starting of nabilone (a synthetic cannabinoid) his pain control was greatly improved and this had a huge impact on his quality of life.

We also managed to significantly reduce his doses of opioid analgesia and ketamine.

We review the current literature regarding the medicinal use of cannabinoids, with an emphasis on chronic pain, in an attempt to clarify their role and how to select patients who may benefit from this treatment.”

http://www.ncbi.nlm.nih.gov/pubmed/23893276

Therapeutic Utility of Cannabinoid Receptor Type 2 (CB2) Selective Agonists.

“The cannabinoid receptor type 2 (CB2), is a class A GPCR that was cloned in 1993 while looking for an alternate receptor that could explain the pharmacological properties of 9- tetrahydrocannabinol. CB2 was identified among cDNAs based on its similarity in amino-acid sequence to the CB1 receptor and helped provide an explanation for the established effects of cannabinoids on the immune system.

In addition to the immune system, CB2 has widespread tissue expression and has been found in brain, PNS and GI tract. Several “mixed” cannabinoid agonists are currently in clinical use primarily for controlling pain and it is believed that selective CB2 agonism may afford a superior analgesic agent devoid of the centrally mediated CB1 effects.

Thus, selective CB2 receptor agonists represent high value putative therapeutics for treating pain and other disease states. In this perspective, we seek to provide a concise update of progress in the field.”

http://www.ncbi.nlm.nih.gov/pubmed/23865723

CB1 Cannabinoid Receptor Agonist Prevents NGF-Induced Sensitization of TRPV1 in Sensory Neurons.

“The transient receptor potential vanilloid type 1 channel (TRPV1) and nerve growth factor (NGF) are important mediators of inflammatory pain…

Cannabinoids, by activating CB1 G protein-coupled receptors, produce analgesia in a variety of pain models, though the exact mechanisms are not known. We tested the hypothesis that activation of the CB1 receptor by cannabinoids attenuates NGF-induced TRPV1 sensitization….

These results support the hypothesis that cannabinoids, acting through CB1 receptors, may produce analgesia in part by preventing NGF-induced sensitization of TRPV1 in afferent nociceptor nerve endings.”

http://www.ncbi.nlm.nih.gov/pubmed/23850608

Pot Users Less Likely to Take Painkiller

“Marijuana and hydrocodone are two of the most widely used and abused drugs in the U.S. But according to a new study by one of the nation’s largest drug screening companies, chronic pain patients who are prescribed hydrocodone are less likely to take the painkiller if they are using marijuana.”

More: http://americannewsreport.com/nationalpainreport/pot-users-less-likely-to-take-painkiller-8819408.html

Marijuana Vaporizer Provides Same Level Of THC, Fewer Toxins, Study Shows

“A smokeless cannabis-vaporizing device delivers the same level of active therapeutic chemical and produces the same biological effect as smoking cannabis…

…smoked cannabis can alleviate the chronic pain caused by HIV-related neuropathy, but a concern was expressed that smoking cannabis was not safe. This study demonstrates an alternative method that gives patients the same effects and allows controlled dosing but without inhalation of the toxic products in smoke,” said study lead author Donald I. Abrams, MD, UCSF professor of clinical medicine.

…pills tend to provide patients with more THC than they need for optimal therapeutic effect and increase side effects.

Patients rated the “high” they experienced from both smoking and vaporization and there was no difference between the two methods by patient self-report of the effect, according to study findings. In addition, patients were asked which method they preferred.

“By a significant majority, patients preferred vaporization to smoking, choosing the route of delivery with the fewest side effects and greatest efficiency,” said Benowitz.”

Read more: http://www.sciencedaily.com/releases/2007/05/070515151145.htm