Science Cannabis

72 THE SCIENCE OF MARIJUANAwas ineffective. These new findings suggest an important role for peripheralsites in mediating the overall analgesic effects of cannabinoids andpoint to potential future applications for topically administered cannabinoidsin pain control.Motility and PostureCannabinoids cause a complex series of changes in animal motility andposture. At low doses there is a mixture of depressant and stimulatoryeffects and at higher doses predominantly CNS depression. In small laboratoryanimals THC and other cannabinoids causes a dose-dependentreduction in their spontaneous running activity. This may be accompaniedby sudden bursts of activity in response to sensory stimuli —reflecting a hypersensitivity of reflex activity. Adams and Martin (1996)described the syndrome in mice as follows:A 9 -THC and other psychoactive cannabinoids in mice produce a "popcorn"effect. Groups of mice in an apparently sedate state will jump(hyperreflexia) in response to auditory or tactile stimuli. As animalsfall into other animals, they resemble corn popping in a popcornmachine.At higher doses the animals become immobile, and will remain unmovingfor long periods, often in unnatural postures — a phenomenon knownas catalepsy.Similar phenomena are observed in large animals. One of the firstreports of the pharmacology of cannabis was published in the BritishMedical Journal a hundred years ago (Dixon, 1899). Dixon described theeffects of extracts of Indian hemp in cats and dogs as follows:Animals after the administration of cannabis by the mouth show symptomsin from three quarters of an hour to an hour and a half. In the preliminarystage cats appear uneasy, they exhibit a liking for the dark, and occasionallyutter high pitched cries. Dogs are less easily influenced and the preliminarycondition here is one of excitement, the animal rushing wildly about