[Effects of furosemide on the excitability of the cerebral cortex]

The effect of furosemide on primary responses of the acoustic brain cortex of unrestrained cats was investigated. The responses were induced by electrical excitation of fibers of the thalamocortical radiation (TCR) and by sound excitation of various intensity and frequency. Furosemide at a dose of 18 mg/kg (intraperitoneally) did not modify primary responses to single stimulation of TCR fibers or their recovery. This diuretic produced an inhibitory effect on primary responses induced by sound excitation. Primary responses that developed in the acoustic cortex to sounds of a frequency of 10,000 Hz showed the highest sensitivity to furosemide. It was found that long-term (10 days) use of furosemide led to enhanced effects of the drug on primary responses to sound excitation.