Exposure of rabbits to methylchloroform. Vestibulardisturbances correlated to blood and cerebrospinal fluid levels

A previously described experimental model for studying the effects on the central nervous system of rabbits, specifically the vestibular apparatus, has been applied to methylchloroform. To achieve a steady concentration the solvent was infused as a lipid emulsion. The blood and cerebrospinal fluid kinetics have been studied. The arterial blood level seems to be closely correlated to the concentration in the central nervous tissue. Vestibular function has been studied by recording the involuntary eye movements — nystagmus — which are elicited via central vestibulo-oculomotor connections. At blood levels of methylchloroform above 75 ppm a so called “positional nystagmus”, indicated vestibular disturbances, is demonstrated. The relationship between the present findings in rabbits and the reaction and blood concentrations in people exposed to industrial solvents, are discussed.