Effect of Adrenocorticotrophic Hormone, Cortisone and Desoxycorticosterone on Brain Excitability.

Abstract

Rats treated with ACTH alone, in a dose of 1 mg. thrice daily, initially showed a slight decrease in EST (electroshock seizure threshold), followed by a return to normal and subsequently a slight increase in threshold. ACTH in doses ranging from 0.001 mg. to 10 mg. effectively antagonized the action of DCA on the EST. Beyond the 12th day of hormone treatment, 0.001, 0.01, 0.05 and 10 mg. of ACTH maintained the EST of DCA-treated rats at a normal or slightly less than normal level. Intermediate doses (0.5 and 3 mg.) produced a secondary rise beginning about the 12th day of the expt. Nevertheless, the final EST values in animals treated with 0.5 and 3 mg. of ACTH were significantly less than in rats given DCA alone. Cortisone alone, in a dose of 1 mg. twice daily, markedly reduced the EST of rats. This dose of cortisone given in combination with DCA resulted in an EST which was lower than normal but higher than that for animals treated with cortisone alone. Cortisone in a dose of 0.1 mg. daily was able to counteract the EST-elevating property of DCA for the 1st 22 days of the expt. Thereafter the EST increased to a final value intermediate between normal and that of rats treated with DCA alone.