Cannabinoids – Influence on the Immune System and Their Potencial Use in Supplementary Therapy of HIV/AIDS

Abstract

Cannabis sativa (Fig. 1.) has been valued for its medicinal as well as its psychotropic properties dating back to ancient times. In nineteenth century W.B. O’Shaughnessy used marijuana for pain relief and Jean-Jacques Moreau de Tours – French psychiatrist, said, that cannabis is very helpful in therapy of psychiatric disorders (Booth, 2004). Main constituents of Cannabis sativa were discovered in 1960’s and named after the plant – cannabinoids. The identification of the chemical structure of cannabis components and the possibility of obtaining its pure constituents were related to a significant increase in scientific interest in this plant. This interest was renewed in the 1990's with the description of cannabinoid receptors and the identification of an endogenous cannabinoid system in the brain (Zuardi, 2006). The most notable of the cannabinoids are: tetrahydrocannabinol (THC) – the most psychoactive substance found in the cannabis plant and cannabidiol – constituent which has displayed sedative effects. Both constituents can be found in the brown resin secreted by the hair which covers female plants (Truta et al., 2002). Cannabinoids bind to the cannabinoid receptors (CB receptors), change metabolism of the cells, moderate neurotransmission and hormones extraction, what affect main functions of the human body (Demuth et al., 2006, ElSohly et al., 2005). The cannabinoid receptor family currently includes two types: CB1, characterized mostly in neuronal cells and brain, and CB2, characterized in immune cells (lymphocytes and macrophages) and tissues (spleen and tonsils) (Demuth et al., 2006). Both receptors are proteins and consist of seven transmembrane−spanning domains (Fig. 2.)(Joy et al., 1999). The CB1 molecule is larger than CB2. However, both receptor molecules are alike in four of the seven regions embedded in the cell membrane (known as the transmembrane regions). The intracellular loops of the two receptor subtypes are quite different, which might affect the cellular response to the ligand (Szulakowska&Milnerowicz, 2007). Human body also produces substances that activate CB receptors, they are known as endocannabinoids. The studies have revealed a broad role of endocannabinoids and cannabinoid receptors in a variety of physiological processes as neuromodulation, pain and appetite sensation, motor learning (Saito et al., 2010).