Cerebrospinal fluid constituents of cat vary with susceptibility to motion sickness

The cerebrospinal fluid drawn from the fourth ventricles of the brains of cats during and after the development of motion sickness was studied to determine what neurotransmitters may be involved in the development of the sickness. The analytical procedure, which uses HPLC coupled with n-electrode coulometric electrochemical detection to measure many compounds with picogram sensitivity, is described. Baseline levels of DOPAC, MHPGSO4, uric acid, DA, 5-HIAA, and HVA were lower on motion and control days in cats which became motion sick when compared with cats which did not. None of the total of 36 identified compounds identified in the samples varied as a function of either exposure to motion or provocation of emesis. It is concluded that susceptibility to motion sickness is a manifestation of individual differences related to fundamental neurochemical composition.