Further investigations on brain distribution of hydra zine and its γ-aminobutyric acid elevating effect in rats

Perry�s hypothesis that hydrazine (Hz) derived from isoniazid (INH) treatment plays an important role in the elevation of brain y-aminobutyric acid (GABA) levels1) was reexamined by measuring Hz and GABA levels in the brain after the treatment with 50 mg/kg of INH or different doses of Hz. The treatment with 50 mg/kg of INH to rats resulted in the elevation of GABA levels in rat whole brain. The maximum levels of GABA increased about twice at 4 h from 2.06 �0.4umol/g wet wt. in the control group to 3-61 �0.4umol/g wet wt. in INH treated group. In this case, brain levels of Hz ranged from 25.6 to 80.8 ng/g wet wt. within 10 h.