Convulsive effects of thiophene, a heterocyclic hydrocarbon: behavioral, electrographic and c-Fos immunocytochemical studies.

The behavioral, electrographic and histopathological changes induced by the heterocyclic hydrocarbon thiophene were investigated in rats following intramuscular injection of 0.3 mL thiophene for 5 days. Generalized convulsions were noted in 29 out of 34 animals (85%) between 1 and 28 h after the final dose. Electroencephalography revealed that the discharges in the hippocampus and forebrain occurred simultaneously, although epileptic activity emerged more strongly from the hippocampus than from any other region. Neuron damage was detected histologically in the temporal and parietal neocortex, piriform gyrus, amygdaloid nucleus and cerebellar cortex, but not in the hippocampus. In contrast, c-Fos was induced widely in the cerebral cortex and hippocampus, and was most marked in the dentate gyrus. These findings suggest that the hippocampus plays a crucial role in seizure onset following thiophene injection.