Glutamine Synthetase Induced Spinal Seizures in Rats

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.

DIAGNOSIS AND TREATMENT OF CYSTICERCOSIS OF CEREBRAL VENTRICLES / 中国寄生虫学与寄生虫病杂志

31 patients with cysticercosis of cerebral ventricles verified by operation or pathological investigation were reported. All patients were between 7 and 64 years of age and 14 were females. All had a single cyst. Since 29 patients (94%) were without a history of intestinal taeniasis, it was proposed that most patients of cysticercosis of cerebral ventricles were caused by hetero-infection and the entrance of Cysticercus into brain ventricle was through choroid plexus along the cerebro-spinal fluid. This is probably the reason why it occurs mostly in the 4th ventricle. The clinical manifestation of cysticercosis of cerebral ventricles were paroxysmal headache and vomiting caused by increased intracranial pressure. Ventricu-lography and CT scanning have considerable diagnostic value. Removal of Cysticercus by surgical operation is successful (Figs. 1 - 8).