NEURAL NETWORKS IN CHEMOTHERAPY-INDUCED DELAYED NAUSEA - A PILOT-STUDY USING POSITRON EMISSION TOMOGRAPHY

Acute but not delayed nausea is well controlled by serotonergic recept or-antagonists implicating different mediation of delayed as compared to acute nausea and vomiting. We report on differences in central neur al activity using positron emission tomographic (PET) measurements of regional cerebral blood flow (rCBF) in two chemotherapy treated cancer patients during delayed severe and mild nausea. Subtractive image met hodology where rCBF during moderate nausea was subtracted from rCBF du ring mild nausea revealed increased neural activity in the anterior hy pothalamus, the vermis, the anterior cingulate gyrus and the thalamus as well as decreased activity in the pens and the substantia nigra. Th ese results may reveal central nervous system substrates underlying de layed nausea and vomiting and are consistent with an interpretation in terms of activation both of serotonergic and noradrenergic but not do paminergic transmitter systems. It is concluded that noradrenergic med iation of delayed nausea is not an unlikely possibility.