Controlled clinical trial of cannabidiol in Huntington's disease

Selective vulnerability in Huntington's disease: preferential loss of cannabinoid receptors in lateral globus pallidus

Selective neuronal vulnerability is a key feature of the neuropathology of Huntington's disease. We used [3H]CP-55,940, a synthetic cannabinoid, to label cannabinoid receptors in tissue sections from individuals dying with Huntington's disease and from normal control subjects. The density of cannabinoid receptors in striatum and pallidum was measured using quantitative autoradiography. There was a greater loss of cannabinoid receptors on striatal nerve terminals in the lateral pallidum compared to the medial pallidum, in Huntington's disease of all neuropathological grades. The disparity in binding density between the lateral and medial pallidum increased with higher grades of disease. There was also a greater loss of receptors in the lateral pallidum than in the putamen. The disproportionate loss of receptors in the lateral pallidum compared to the putamen increased in magnitude with severity of neuropathological grade. These data support the relative preferential loss or dysfunction of striatal neurons projecting to the lateral pallidum compared to neurons projecting to the medial pallidum. Terminals in the lateral pallidum containing cannabinoid receptors may be affected earlier or more severely than terminals in the medial pallidum, and both pallidal segments may be affected before or more severely than cell bodies or dendrites in the striatum. Terminal loss of markers may represent a response to perikaryal injury or dysfunction, or less likely, may indicate the primary site of neuronal damage in Huntington's disease.

Effects of ipsapirone and cannabidiol on human experimental anxiety

The effects of ipsapirone and cannabidiol (CBD) on healthy volunteers submitted to a simulated public speaking (SPS) test were compared with those of the anxiolytic benzodiazepine diazepam and placebo. Four independent groups of 10 subjects received, under a double-blind design, placebo or one of the following drugs: CBD (300 mg), diazepam (10 mg) or ipsapirone (5 mg). Subjective anxiety was evaluated through the Visual Analogue Mood Scale (VAMS) and the State-trait Anxiety Inventory (STAI). The VAMS anxiety factor showed that ipsapirone attenuated SPS-induced anxiety while CBD decreased anxiety after the SPS test. Diazepam, on the other hand, was anxiolytic before and after the SPS test, but had no effect on the increase in anxiety induced by the speech test. Only ipsapirone attenuated the increase in systolic blood pressure induced by the test. Significant sedative effects were only observed with diazepam. The results suggest that ipsapirone and CBD have anxiolytic properties in human volunteers submitted to a stressful situation.