Structure-activity relationships of intracerebrally injected tremorigenic indole alkaloids

The indole alkaloids harmane, harmine, ibogaine, iboxygaine and ibogaline caused tremor in mice when injected intracerebrally. Harmol, voacangine, voacristine and conopharyngine were inactive in this respect. Chemical structure strongly influences tremorigenic potency which is increased by a methoxy group and reduced or abolished by a hydroxy or carbomethoxy group. The great importance of chemical structure for tremorigenic power of indole alkaloids points to specific receptors for these drugs in the brain.