Glutamine Synthetase Induced Spinal Seizures in Rats.
10.3349/ymj.2003.44.1.125
- Author:
Dong Won SHIN
1
;
Young Sul YOON
;
Masato MATSUMOTO
;
Wencheng HUANG
;
Phil CERAULO
;
Wise YOUNG
Author Information
1. Department of Neurosurgery, Yongdong Severance Hospital, Yonsei University College of Medicine, 146-92 Dogok-dong, Kangnam-gu, Seoul 135-720, Korea. ysyoon@yumc.yonsei.ac.kr
- Publication Type:Original Article
- Keywords:
Glutamine synthetase;
spinal seizure;
EMG;
molecular effect
- MeSH:
Animals;
Electromyography;
Female;
*Glutamate-Ammonia Ligase/administration & dosage;
Injections, Spinal;
Male;
Rats;
Rats, Long-Evans;
Seizures/*chemically induced/physiopathology;
Spinal Cord Diseases/*chemically induced/physiopathology
- From:Yonsei Medical Journal
2003;44(1):125-132
- CountryRepublic of Korea
- Language:English
-
Abstract:
Glutamine synthetase (GS) is a key enzyme in the regulation of glutamate neurotransmission in the central nervous system. It is responsible for converting glutamate to glutamine, consuming one ATP and NH3 in the process. Glutamate is neurotoxic when it accumulates in extracellular fluids. We investigated the effects of GS in both a spinal cord injury (SCI) model and normal rats. 0.1-ml of low (2-microM) and high (55-microM) concentrations of GS were applied, intrathecally, to the spinal cord of rats under pentobarbital anesthesia. Immediately after an intrathecal injection into the L1-L3 space, the rats developed convulsive movements. These movements initially consisted of myoclonic twitches of the paravertebral muscles close to the injection site, repeated tonic and clonic contractions and extensions of the hind limbs (hind limb seizures) that spread to the fore limbs, and finally rotational axial movements of the body. An EMG of the paravertebral muscles, fore and hind limbs, showed the extent of the muscle activities. GS (2-microM) caused spinal seizures in the rats after the SCI, and GS (6-microM) produced seizures in the uninjured anesthetized rats. Denatured GS (70 degrees C, 1 hour) also produced spinal seizures, although higher concentrations were required. We suggest that GS may be directly blocking the release of GABA, or the receptors, in the spinal cord.
