The action of dieldrin on regional brain blood flow in the rat

Abstract

The actions of the chlorinated hydrocarbon insecticide dieldrin upon auditory evoked response and regional blood flow were studied in four brain regions of conscious rats. In the absence of seizure activity parallel increases in blood flow and evoked response amplitude were seen, with large increases in the cerebral cortex and much smaller effects in the cerebellum and brainstem. These effects were consistent with the known regional selectivity of action of dieldrin and with a close coupling of local blood flow and presumed metabolic demand. The pattern was, however, disrupted by the occurrence of seizures which produced a marked but transient depression in the auditory evoked response and a similarly marked but presistent depression of blood flow. This resulted in a normal blood flow but enhanced evoked response during the later postictal period, which may represent a seizure induced deficiency in flow regulation.