Seizure-Related Change of NADPH-diaphorase and Calbindin D28k Positive Neurons in the Cerebral Cortex of Rats / 대한해부학회지

ABSTRACT

Administration of kainate (KA) results in the induction of epileptiform activity and limbic motor seizures. Nitric oxide (NO) is a gaseous messenger that plays a role in neural transmission, long term potentiation, depression and cerebral blood flow. NO is formed by NO synthase (NOS) from arginine. NO mediates the increase in cerebral blood flow during seizure activity. However, the production site of NO has not been clearly defined. Recent report showed that constitutive NOS may be induced under certain conditions. Therefore, the present study was aimed to investigate the change of NOS and calbindin D28k in the rat cerebral cortex following seizure. Rats were injected with KA and killed at 6 hours, 1, 3, 6 and 12 days after seizure. Expressional change of nNOS and calbindin D28k was assessed by histochemistry, immunohistochemistry and RT-PCR in the rat brain. Induced NADPH-d positive neurons were observed in the cerebral cortex of 1, 3, 6 and 12 days after seizure and found in specific cortical areas, such as motor cortex, somatosensory cortex, auditory cortex, visual cortex, ectorhinal cortex and perirhinal cortex. The level of nNOS mRNA increased at 1, 3, 6 and 12 days after seizure compared with control group. Induced calbindin D28k positive neurons were observed in motor cortex and somatosensory cortex 1 and 3 days after seizure. The level of calbindin D28k mRNA in the cerebral cortex was slightly decreased at 1 day after seizure. Therefore, in this study, the induced NADPH-d, calbindin D28k positive neurons and upregulated NADPH-d positive neurons may influence the cerebral blood flow and neuronal activity in the cerebral cortex during post-seizure period.