THE IN VIVO EFFECTS OF HYDRAZINES AND VITAMIN B₆ ON THE METABOLISM OF GAMMA-AMINOBUTYRIC ACID

¹ Experimental Toxicology Branch, USAF School of Aerospace Medicine, Aerospace Medical Division (AFSC), Brooks Air Force Base, Texas

Rats injected with hydrazine, unsymmetrical dimethylhydrazine, monomethylhydrazine and symmetrical dimethyihydrazine showed a significant inhibition of glutamic acid decarboxylase and GABA-transaminase. Hydrazine caused an increase in brain gamma-aminobutyric acid while the other three hydrazines produced a depression of GABA levels.

Injection of pyridoxal or pyridoxal phosphate with UDMH, MMH or hydrazine caused a decrease in the time required for onset of convulsions. No convulsions were observed with SDMH with or without the vitamins. No direct relationship could be demonstrated between the onset of convulsive activity and the inhibition produced in the rats.

Pyridoxine treated rats did not convulse when hydrazine, MMH or UDMH was simultaneously administered. No correlation could be found between the protective effect of PY and the inhibition of GAD or GABA-transaminase.

A direct relationship between the metabolism of GABA in whole rat brains and the convulsive action of hydrazines with or without B₆ vitamins could not be shown.