Cannabis pharmacological effects

There are pharmacological, social and legal issues to consider in this context of drug dependence and, of course, drug users and abusers vary enormously. A chronic alcoholic is very different from a weekend user of cannabis and any consideration of the topic has to consider legal and social issues as well as pharmacological effects of the drugs. 

Before the discovery of specific cannabinoid receptors, the term cannabinoid was used to describe the biologically active constituents of the Cannabis sativa plant, including A -THC (67), cannabidiol (68) and their analogues and derivatives, many of which have characteristic pharmacological effects. 

Some precipitants of HPPD are cannabis use, anxiety, fatigue, and sudden movement into a dark environment. This may be a normal function of memory that becomes exaggerated due to the intense nature of the hallucinogenic experience. Alternately, it may also be a direct pharmacological effect. 

The primary active component of cannabis is A9-tetrahy-drocannabinol (THC), which is responsible for the greater part of the pharmacological effects of the cannabis complex. A8-THC is also active. However, the cannabis plant contains more than 400 chemicals, of which some 60 are chemically related to A9-THC, and it is evident that the exact proportions in which these are present can vary considerably, depending on the way in which the material has been harvested and prepared. In man, A9-THC is rapidly converted to 11-hydroxy-A9-THC (5), a metabolite that is active in the central nervous system. A specific receptor for the cannabinols has been identified it is a member of the G-protein-linked family of receptors (6). The cannabinoid receptor is linked to the inhibitory G-protein, which is linked to adenyl cyclase in an inhibitory fashion (7). The cannabinoid receptor is found in highest concentrations in the basal ganglia, the hippocampus, and the cerebellum, with lower concentrations in the cerebral cortex. 

Cannabinoids are able to cause different effects at the level of various systems and/or organs the most important effects occur on the central nervous system and on the cardiovascular system. In fact, they are able to affect mood, memory, motor coordination and cognition, and they increase heart rate and variate the systemic arterial pressure. Furthermore, it is well known the capability of cannabinoids to reduce intraocular pressure and to affect the respiratory and endocrine systems (L. E. Hollister, Health Aspects of Cannabis, Pharmacological Reviews, 38,1-20,1986). More recently, it was found that they suppress the cellular and humoral immune response and have antiinflammatory properties (A. W. Wirth et al.. Antiinflammatory Properties of Cannabichromene, Life Science, 26,1991-1995,1980). 

The investigations conducted to date on the pharmacological effects mediated by cannabinoid receptors show that the non-psychoac-tive effects of Cannabis derivatives are mediated by CB2 peripheral receptor. Furthermore, the CB2 receptor localization proves that said non-psychoactive effects, i.e. the effects on the immune system, the anti-inflammatory, myorelaxant and antinociceptive effects, as well as the effects on pressure systems, are mediated by said receptor. 

Because of the widespread use of Cannabis preparations all over the world, it has become necessary to study the pharmacology and toxicity of the active constituent, viz. A9-THC in greater detail. In the past, attempts to study the pharmacological effects of this compound have been hampered by variations in the potency of the plant material. Accordingly, a supply of pure sjmthetic material is essential to carry out these studies as well as to enable accurately reproducible dosages of the active ingredient to be used for its pharmacological properties. 

Mason AP, McBay AJ (1985) Cannabis pharmacology and interpretation of effects. J Forensic Sci 30 615-631... 

The cannabis plant has been cultivated for centuries both for the production of hemp flber and for its presumed medicinal and psychoactive properties. The smoke from burning cannabis contains many chemicals, including 61 different cannabinoids that have been identified. One of these, A-9-tetrahydrocannabinol (A-9-THC), produces most of the characteristic pharmacological effects of smoked marijuana. 

A detailed description of the pharmacological effects of Cannabis was already accessible to Greek and Roman physicians in the first century AD, when Dioscorides included the plant in his classic textbook of Materia Medica (Fig. 6.2). As expected from the wide distribution of Cannabis in the Far East, ancient Indian and Chinese medical writers were also familiar with its therapeutic usage and were indeed much more accurate than their European... 

Based on the role of endocannabinoids and cannabinoid receptors in several pathological conditions, the pharmacological manipulation of their levels or action is being developed as a therapeutic strategy. Enhancement of endocannabinoid signalling when this plays uniquely a protective role can be effected in a safer way using (i) cannabis extracts in which the presence of non-psychotropic cannabinoids with therapeutic activity per... 

Lastly, on December 1,2003, the National Institute of Drug Abuse (NIDA) published an official notice seeking grant applications focusing on the identification, evaluation and development of safe and effective pharmacological treatments for cannabis-related disorders (CRDs). A section of this notice, titled Targeting Children, explained ... 

Vieira, J. E. V., G. S. G. Barros, M. C. Medeiros, F. J. A. Matos, M. P. Souza and M. J. Medeiros. Pharmacologic screening of plants from Northeast Brazil. II. Rev Brasil Farm 1968 49 67-75. Dixit, V. P., V. N. Sharma and N. K. Lohiya. The effect of chronically administered cannabis extract on the testicular function of mice. Eur J Pharmacol 1974 26 111-114. Pinheiro de Sousa, M. and M. Z. Rouquayrol. Molluscicidal activity of plants from Northeast Brazil. Rev Bras... 

Hardman, H.F., and Hosko, M.J. Autonomic effects An overview of the cardiovascular-autonomic actions of cannabis. In Braude, M.C., and Szara, S., editors. The Pharmacology of Marihuana. 

Cannabis and some cannabinoids relieve pain. However, the therapeutic doses are essentially equivalent to the doses that cause CNS effects and, except in very specific conditions (possibly migraine) they are of limited use. Although several companies have produced a large number of derivatives, as previously reviewed in this series [1] and elsewhere [105,107] the situation has not changed. No practical separation of activity has been achieved, except with the synthetic cannabinoid HU-211 (see below) which does not bind to either CBi or CB2. Hence most of the work reported in the last decade deals mainly with the pharmacology of pain reduction by cannabinoids, rather than with drug discovery and development. 

The plant Cannabis sativa has been used by humans for thousands of years, both for the effects when ingested and for making rope from the fibers in the stem. The major constituent of pharmacological interest is Ag-tetrahy-... 

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