[Cannabinoids--signal transduction and mode of action]

Abstract

The therapeutic use of cannabinoids, the components of cannabis sativa L., was investigated in numerous researches in detail. Animal studies revealed that cannabinoid receptor agonists alter pain-associated behaviour, have immune-suppressive properties, suppress tumor growth, modulate sensitisation processes and influence memory and learning. Those effects are mediated by two membrane-bound cannabinoid receptors and as mechanisms of signal transduction blockade of ion channels, inhibition of adenylate cyclase and retrograde inhibition of neurotransmitter release are currently being discussed. In clinical studies oral administration of cannabinoids indicated beneficial results during the therapy of multiple sclerosis, weight loss, nausea and vomiting due to chemotherapy, and intractable pruritus. However, therapy of chronic pain conditions revealed conflicting results and unequivocal success could not have been delivered due to unwanted side effects. Further multicentre studies are required to estimate cannabinoids as novel therapeutic tools for the treatment of chronic pain.