Cannabinoid receptor Cannabis sativa effects

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. 

Marijuana and hashish are derivatives of the cannabis sativa plant 919 Cannabinoid effects in the CNS are mediated by the CB1 receptor 919 Endocannabinoids are endogenous ligands for the CB1 receptor 919 Endocannabinoids serve as retrograde messengers 920 There are many similarities between endogenous opioid and cannabinoid systems 921... 

Cannabis sativa plants contain at least 400 different compounds, of which as many as 60 are structurally related to 5 -tetrahydrocannabinol (5 -THC), the primary psychoactive constituent of cannabis. When cannabis is smoked, hundreds of additional compounds are produced by pyrolysis, which may contribute to both acute and chronic effects (Abood and Martin, 1992). The central nervous system actions of canna-binoids are mediated primarily through the CBj receptor. A second type of cannabinoid receptor, termed the CB2 receptor, is distributed primarily in the periphery (Gifford et ah, 1999). Activation of central cannabinoid receptors modulates neurotransmitter release at... 

Cannabinoids, the active components of Cannabis sativa and their derivatives, act in organisms by mimicking endogenous substances—the endocannabinoids anandamide and 2-arachidonoylglycerol—that bind to and activate specific cannabinoid receptors. So far, two cannabinoid-specific Gj/o protein-coupled receptors, CBl (Matsuda et al. 1990) and CB2 (Munro et al. 1993), have been cloned and characterised from mammalian tissues. Most of the effects of cannabinoids rely on CBi receptor activation. This receptor is particularly abundant in discrete areas of the brain, but is also expressed in peripheral nerve terminals and various extra-neural sites such as testis, eye, vascular endothelium and spleen. In contrast, the CB2 receptor is almost exclusively present in the immune system (Howlett et al. 2002). 

The principal agent responsible for these effects is A -tetrahydrocannabinol (A -THC), the major psychoactive component of Cannabis sativa. /1 -THC can interfere, not only with the activity of classical neurotransmitters but also with the activity of the endogenous cannabinoid system itself. Different studies support a role for this system in brain development and maturation, and several of its components have been characterized (receptors, endogenous ligands, and metabolism pathways). The effects of /1 -THC were caused by the activation of cannabinoid receptors, which emerge early in the developing brain (Ferndndez-Ruiz et al. 1992, 1994,1996,1999, 2000). 

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