Developmental mRNA Expression of cdk5 and its Putative Regulators, p67 and p35, in Rat Brain / 대한해부학회지

Cyclin-dependent kinase 5 (cdk5) is essential for brain development and p35 and p67 are the regulatory molecules for cdk5. In this study, we have investigated the expression of cdk5, p35, and p67 mRNAs in the developing rat brain with in situ hybridization histochemistry. The expression of cdk5 mRNA was already observed in embryonic day 12 (E12), start point of neurogenesis in rat brain, throughout the brain and gradually increased until postnatal day 3 (P3). At this period, strong expression of cdk5 mRNA was observed in the cerebral cortex, hippocampus, dentate gyrus, thalamus, hypothalamus, and inferior colliculus. High level of cdk5 expression was maintained in the postnatal rat brain and prominent expression was observed in the hippocampus, dentate gyrus, cerebellum, and choroid plexus of adult rat brain. Strong expression of p35 mRNA was observed between E16 and E20 in the cerebral cortex, hippocampus, dentate gyrus, thalamus, hypothalamus, and inferior colliculus as like as cdk5. After birth, the expression of p35 mRNA was gradually decreased and significant differences in the expression of cdk5 and p35 were observed in the thalamus, hypothalamus, midbrain, and cerebellum. In the embryonic period, the expression pattern of p67 was very similar with that of p35 but expression level was lower than p35. After birth, strong expression of p67 was observed in the areas where the expression of cdk5 was high. From these results, it is suspected that p35 may function in neuronal migration, and p67 in differentiation and maturation, as a major regulator for cdk5 in developing rat brain.

The effect of convulsive treatments on the expression of heat shock protein 72 mRNA in the rat brain / 대한해부학회지

Recently, there are numerous efforts to explain the psycho-, neurological events through molecular biological standards. Because of the property as a strong stimulant to neural cells, convulsions induced by electroconvulsive shock (ECS) or kainic acid are used for neurobiological research. In this study, the effect of systemic administration of kainic acid and ECS on the expression of hsp 72 mRNA in the rat brain was investigated with in situ hybridization histochemistry. The induction of hsp 72 mRNA was observed in the dentate gyrus from 2 hr after KA treatment. After that, the expression was gradually increased in the various areas including dentate gyrus, hippocampus, olfactory bulb, cerebral cortex, caudate-putamen, thalamus, and peaked at 9 hr after KA treatment. At the 72 hr after KA treatment, weak expression was found only in the CA3 area of hippocampus. However, the expression of hsp 72 mRNA was not detected in any ESC treated rat brains, we examined.The inducton of c-fos was observed from 15 min, peaked at 6 hr, and returned to basal level at 48 hr after KA treatment. The expression of c-fos was observed in the same areas that showed induction of hsp 72 mRNA. In the ECS treated rat brains, the induction of c-fos was found in the dentate gyrus, olfactory bulb and cerebral cortex at 15 min and 30 min after ESC. From these results, it may be suggested that the effects of KA treatment and ECS on the neuronal cells are different, and it is due to difference in induction mechanism of convulsion between KA and ECS. And, the similarity between the expression pattern of hsp 72 mRNA by KA and KA receptor suggests that the induction of hsp 72 mRNA is based on the direct effect of KA through KA receptor.

Cloning and localization of novel stage-specific gene (PKrCb1) of the postnatal rat cerebellum / 대한해부학회지

In rat that is helpless at birth, the cerebellum is in a corresponding state of immaturity, and its histogenesis and morphogenesis mainly occur after birth. The times and sites of origin of the four types of cerebellar local-circuit neurons, as well as their migration routes to specific positions in the cortex, their distinctive patterns of differentiation and growth, and their synaptogenesis, have been well studied. The stage-specific genes in the postnatal rat cerebellum may be related with these kind of neural development in the cerebellum. To clone the genes related with neural development in the postnatal cerebellum, developmentally differentially expressed genes were screened from postnatal rat cerebellum with ordered differential display (ODD) and the developmental expression pattern in the postnatal rat cerebella was investigated with in situ hybridization histochemistry. One novel postnatal stage-specific gene (PKrCb1) was cloned by ODD with 7 cDNA pools (P0, P3, P7, P12, P18, P25, adult rat cerebella). To investigate the developmental expression pattern of this novel gene on the cell level, in situ hybridization histochemistry was performed in the developing and adult rat brain sections. The developmental expression pattern of PKrCb1 in the cerebellum was well matched with spatiotemporal migration pattern of granule cells and it may be suspected that PKrCb1 is related with migration of granule cells from external granular layer to internal granular layer. From the results, it is suggested that the methods used in this experiment will be the powerful methods for the cloning and primary function study of the genes related with cerebellar development.

The effect of kainic acid induced convulsions on the expression of inositol 1,4,5-trisphosphate receptor mRNA in the rat brain / 대한해부학회지

In this study, the effect of systemic administration of kainic acid (KA) on the expression of inositol 1,4,5-trisphosphate receptor mRNA in the rat brain was investigated with in situ hybridization histochemistry. After the injection of KA in a convulsive dose (10 mg/kg i.p.), inositol 1,4,5-trisphosphate receptor mRNA was reduced significantly in dentate gyrus, cerebral cortex, and caudate-putamen and moderately in CA1-CA3 areas of hippocampus and cerebellum. In dentate gyrus, the expression of inositol 1,4,5-trisphosphate receptor mRNA was significantly decreased at 6 h, lowest level at 9 h, after that the expression was gradually recovered and returned to basal level at 72 h after KA injection. However, in the CA1-CA3 areas of the hippocampus, cerebral cortex, and caudate-putamen, the expression of inositol 1,4,5-trisphosphate receptor mRNA was abruptly decreased at 9 h and almost return to basal level at 24 h after KA injection. The significant repression of inositol 1,4,5-trisphosphate receptor mRNA in cerebellum was only found at 9 h after KA injection. But significant change of inositol 1,4,5-trisphosphate receptor mRNA was not found in the brains of rats treated with NMDA receptor blocker, MK-801, followed by KA injection. These observations suggest that the inositol 1,4,5-trisphosphate receptor is one of the genes whose expression can be altered by KA treatment and the NMDA receptor is related with this alternation.

The developmental expression of voltage dependent calcium channel alpha1 subunits (alpha1D, alpha1B, alpha1A, alpha1E) mRNA in the rat brain / 대한해부학회지

Voltage dependent calcium channels (VDCCs) mediate Ca++ influx into cells and are responsible for regulation of a variety of physiological effects. The key functional property of VDCCs are attributed to the calcium-pore forming alpha1 subunit. In this study, distribution pattern of alpha1 subunit (alpha1D, alpha1B, alpha1A, alpha1E) mRNA of VDCCs in developing and adult rat brain was investigated by in situ hybridization histochemistry. In the adult rat brain, each alpha1 subunit mRNA displayed a specific and distinct distribution pattern. alpha1D was highly expressed in the olfactory bulb, dentate gyrus, pituitary gland, pineal gland, hypothalamus, superior colliculus and cerebellum. Relatively low level of alpha1B was expressed throughout the whole brain and strong expression of alpha1A was observed in CA3 area of Ammon's horn, medial geniculate body, inferior colliculus and cerebellum. High level of alpha1E was found in the olfactory bulb, hippocampus, dentate gyrus, medial habenular nucleus and cerebellum. Moreover, alpha1B, alpha1A and alpha1E were expressed only in the nervous system but alpha1D was expressed not only in the nervous system but also in other tissues including liver, heart, lung and skeletal muscle. Generally the expression of alpha1D, alpha1A, and alpha1E subunit was observed from E14 and thereafter the intensity of labeling was gradually increased to P14 and then decreased to the adult level. But the expression of alpha1B subunit was observed from E14 and gradually increased to E20 and P0 and then decresaed. From the differential expressions of VDCC alpha1 subunits in developing and adult rat brain, it is suggested that each type of VDCCs may play a distinct roles in neural and nonneural tissues, and the VDCCs may be related with development of nervous system.

The effects of testosterone on the pituitary growth hormone secretion

No abstract available.