Effects of ibogaine on sensory-motor function, activity, and spatial learning in rats.

Ibogaine, a naturally occurring alkaloid, reduces withdrawal symptoms from morphine but also impairs sensory-motor function, activity, and learning in rats. At doses of 20-60 mg/kg, rats showed slower response times and motor reflex impairments at 40-60 mg/kg. Locomotor and nonlocomotor activity, as well as emotionality, were reduced at 10-40 mg/kg, with near-inactivity at higher doses. Learning a spatial location task was also impaired, likely due to reduced activity and sensory detection. A single 40 mg/kg injection caused learning deficits 1 day after, but not 7 days after, without affecting sensory-motor function at those times. Thus, ibogaine produces acute sensory-motor and activity problems and long-term learning deficits without lasting sensory-motor changes.

Study at a glance

Abstract

Ibogaine, a naturally occurring alkaloid, has been show to reduce naloxone-precipitated withdrawal symptoms from morphine. Given the clinical possibilities, it is important to determine ibogaine's effects on sensory-motor function, activity, learning, and memory. Long-Evans rats injected with doses of 20-60 mg/kg of ibogaine displayed slower response times on sensory and sensory-motor tests and were impaired in performing specific motor reflexes at doses of 40-60 mg/kg. Furthermore, these rats showed a marked reduction in locomotor and nonlocomotor activity, as well as emotionality at doses ranging from 10-40 mg/kg. At the higher doses the rats appeared to be virtually inactive. There were also deficits in learning a spatial location task (a dry-land version of the Morris water-maze). The deficits, however, were probably due to a reduction in locomotor activity and reduction in detection of sensory information. In a final experiment, a single injection of 40 mg/kg of ibogaine had marked deleterious effects on the acquisition of the spatial location task 1 but not 7 days after the injection, even though in this case there were no effects on sensory motor function 1 or 7 days after the injection. Thus, there are severe sensory-motor activity and learning problems while the animal is under the influence of ibogaine (acute effect) as well as long-term consequences on learning without concomitant changes in sensory-motor function.