Seizure -Related Change of NADPH -diaphorase and Calcium Binding Protein Positive Neurons in the Brain of Rats / 체질인류학회지

Nitric oxide (NO) is a gaseous messenger that plays a role in neurotransmission, long term potentiation, depression and cerebral blood flow. Increases in intracellular calcium levels activate the enzyme NOS, and the NO released then diffuse to adjacent cells and activate guanylate cyclase. NO mediates the increase in cerebral blood flow during seizure activity. Therefore, the present study was aimed to investigate the change of NOS and calcium binding proteins in the rat cerebral cortex following seizure. Rats were injected with kainate (KA) and killed at 6 hours, 1, 3, 5 and 10 days after seizure. Expressional change of nNOS, calbindin D28k and parvalbumin was assessed by histochemistry, immunohistochemistry and microdensitometry in the rat brain. The intensity of the NADPH -d staining in rat cortical neurons showed a marked susceptibility to KA administration. At 6 hours and 3 days after seizure, the optical density of the NADPH -d staining was increased relative to the signal in saline treated control rats. At 5 and 10 days after seizure, the optical density of NADPH -d staining was not significantly different in most cortical regions compared to controls. In the hippocampus, the optical density of NADPH -d staining was highest at 5 days after seizure. The optical densities of calbindin D28k and parvalbumin positive neurons were various in the cerebral cortex, hippocampus and caudatoputamen during postseizure period. These results indicate that the calcium binding proteins investigated here are not essential for determining the activation of nNOS/NADPH -d positive neurons in the cerebral cortex and striatum.

Sequential Change of Nitric Oxide Synthase in Rat Hippocampus after Kanic Acid-induced Seizure / 대한해부학회지

We have investigated the neural cell damage and the change in the expression of NOS in the rat hippocampus, one of the brain structures most vulnerable to seizures. Rats were injected with kainic acid (KA) and sacrificed 6 h, 1 d, 3 d and 6 d after KA administration. The neural cell damage and the expression pattern of NOS was studied using silver impregnation, NADPH-diaphorase (NADPH-d) histochemistry and reverse transcription-polymerase chain reaction (RT-PCR) analysis. Silver impregnation revealed that kainic acid caused pyramical cell damage which was most severe in the CA1/CA2 subfield and hilus and to a lesser degree in the CA3 region. The optical densities of NADPH-d-positive neurons in the CA1, CA3 and dentate gyrus (DG) regions of the hippocampus were shown to have increased in samples obtained 1 d and 3 d after injection of KA. The number of NADPH-d-positive neurons in the CA1 and CA3 regions of the hippocampus was shown to have decreased in samples obtained 3 d and 6 d after injection of KA. However, the number of NADPH-d-positive neurons in the DG region did not change significantly. The increase in the levels of nNOS, iNOS and eNOS mRNA reached maximal values in samples obtained 1 d after KA treatment. Our findings indicate that the KA-induced seizures induce neural cell damage, increase NOS activity and upregulate the expression of NOS mRNA, which suggests the possibility of a functional role of NOS in bringing about changes in the cells in the hippocampus following seizures.

Expressional Change of Endothelial Nitric Oxide Synthase in Rat Cerebral Cortex after Kainic Acid-Induced Seizure / 대한해부학회지

Administration of kainic acid (KA) results in induction of epileptiform activity and motor seizures. Nitric oxide (NO) mediates the increase in cerebral blood flow during seizure activity. However, the production site of NO has not been clearly defined. Recent studies showed that constitutive nitric oxide synthase may be induced under certain conditions. Therefore, this study was aimed to investigate the change in endothelial nitric oxide synthase (eNOS), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) since these are involved in cerebral blood flow. Rats were treated with KA and killed at 6 hours, 1, 3, 6 and 12 days after seizure. Expressional changes were assessed by immunohisto-chemistry and RT-PCR. eNOS was detected in the blood vessels of the cerebral cortex of the control group, but was not detected in neurons. eNOS-positive neurons were induced in the cerebral cortex at 1 and 3 days after seizure and found in specific cortical areas, such as primary motor cortex, secondary motor cortex, primary somatosensory cortex, secondary somatosensory cortex, insular cortex, ectorhinal cortex, parietal association cortex, temporal association cortex, auditory cortex and visual cortex. The levels of eNOS mRNA increased at 1 and 3 days after seizure compared to controls. The staining intensity of eNOS-positive microvessels was elevated in samples obtained 1, 3, and 6 days after seizure compared to the control group. However, NPY- and VIP-positive neurons, and glial fibrillary acidic protein-positive astrocytes were not induced in the cerebral cortex after seizure. Therefore, specific neuroactive substances may be induced in the cerebral cortex after seizure. Nitric oxide, a free radical synthesized in the brain by NOS, is a messenger molecule that mediates vascular dilatation and neural transmission. Therefore, neurons showing induced eNOS-positivity and upregulated eNOS-positive microvessels may affect the cerebral blood flow and neuronal activity in the cerebral cortex after seizure.

Expressional Change of Nitric Oxide Synthase and erbB4 in Rat Hippocampus after Seizure / 대한해부학회지

Nitric oxide has been considered to be an important modulator of the epileptic seizure response. Previous studies have mainly focused on the nitric oxide synthase (NOS) expressed in glial cells and vascular endothelial cells in the brain following seizures, while less data have been available reading the change of neuronal NOS (nNOS) produced in neurons. Polypeptide growth factors play a central role in a variety of environmentally induce structural changes in the cortex and hippocampus of adult brain. neuregulin is widely expressed in the central and peripheral nerve cells and Schwann cells, glia, oligodendrocytes and muscle cells, to control cellular proliferation, differentiation and migration. erbB family are the receptors of the neuregulin and consist of erbB2, erbB3 and erbB4. We have, therefore, investigated the change in the expression of nNOS and erbB4 in the rat hippocampus, one of the brain structures most vulnerable to seizures. Rats were injected with kainic acid (KA) and sacrificed 6 h, 1 d, 3 d and 6 d after KA administration. The expression pattern of nNOS and erbB4 was studied using reverse transcription-polymerase chain reaction analysis, NADPH-diaphorase (NADPH-d) histochemistry and immunohistochemistry. The increase in the level of nNOS reached maximal values in samples obtained 1 d after KA treatment. The optical densities of NADPH-d-positive neurons in the CA1 and dentate gyrus (DG) regions of the hippocampus were shown to have increased in samples obtained 1 d and 3 d after injection of KA. The number of NADPH-d-positive neurons in the CA1 regions of the hippocampus was shown to have decreased in samples obtained 3 d and 6 d after injection of KA. However, the number of NADPH-d-positive neurons in the DG region did not change significantly. We show that erbB4 immunoreactivity is increased in hippocampus, reaching maximal levels 3 d after KA treatment, some NOS neurons contain erbB4 protein. We propose that the survival of NOS neuron in the hippocampus after injection of KA is associated with expression of erbB4, neuregulin receptor.

Metabolism of C(14)-glucose by plerocercoid of Diphyllobothrium sp

The glucose uptake rate by plerocercoid of Diphyllobothrium sp. was a mean value of 5.35+/-0.80 micro-mole/hr/g of wet wt, and total CO(2) production rates by the plerocercoid larva averaged 7.54+/-0.73 micro-mole/hr/g of wet wt. The relative specific activity into respiratory CO(2) showed a mean value of 7.30 +/-0.90 per cent. The rate of CO(2) production derived from medium C(14)-glucose was a mean of 0.58+/-0.13 micro-mole/hr/g of wet wt. Therefore, the average value of 1.92+/-0.38 per cent of glucose utilized by the larvae from the medium C(14)-glucose was oxidized to respiratory CO(2). The tissue concentration of glycogen in plerocercoid larva was a mean of 46.28 +/-2.23 mg/g or 4.63+/-0.22 per cent/g of wet wt., and the turnover rate of glycogen pool was a mean of 0.049 +/- 0.012 %/hr or 0.010 +/- 0.003 mg/hr/g of wet wt. The average value of 2.76+/-1.00 per cent of glucose utilized by the larvae from the medium C(14)-glucose was incorporated to the glycogen. These data accounts for that only 5 per cent of the utilized glucose by the plerocercoid larvae participated in furnishing the oxidation into respiratory CO(2) and the synthetic process into glycogen.