Susceptibility of Chick Brain L-Glutamic Acid Decarboxylase and Other Neurotransmitter Enzymes to Hyperbaric Oxygen in Vitro,
SASKATCHEWAN UNIV SASKATOON DEPT OF BIOCHEMISTRY
Pagination or Media Count:
Many enzymes are inhibited by oxygen at high pressure OHP, and these OHP-sensitive enzymes possess essential sulphydryl groups. Since many enzymes contain sulphdryl groups necessary for their activity, including several neurotransmitter enzymes, it is to be expected that enzymes other than L-glutamic acid decarbohylase GAD that are directly involved in neurotransmitter metabolism will be inhibited by hyperbaric oxygen. However, if low gamma-aminobutyric acid GABA levels are the prime cause of seizures induced by OHP, it might be expected that GAD activity is somehow selectively inhibited. This selectivity could simply be due to GAD being extremely sensitive to inhibition by OHP. The investigation tested this supposition by comparing the relative susceptibilities of the activity of several chick brain enzymes to OHP in vitro. These enzymes are all directly involved in the metabolism of putative neurotransmitters, namely GABA, acetylcholine, dopamine, noradrenaline and 5-hydroxytryptamine. Of the ten enzymes studied, the activity of GAD is the most sensitive to inhibition by oxygen.
- Stress Physiology