Changes of TH Immunoreactivities and Melatonin Treatments in the Rat Brain by Chronic Stress / 대한해부학회지

These experiments were performed to investigate the effect of saline, melatonin, stress, stressedmelatonin on TH immunoreactivity in rat brain. The animals were injected with melatonin (1 mg/kg, i.p.) after electric shocks for 15days. The results were as follows; 1. TH immunoreactive neurons in brain (the number of staining neuron & the stain intensity in LC and parietal cortex, the stain intensity in arcuate nucleus and median eminence of cerebral cortex) were significantly increased in stressed group compared with all the other groups. 2. TH immunoreactive neurons in brain (the number of staining neuron & the stain intensity in LC and parietal cortex, the stain intensity in arcuate nucleus and median eminence of cerebral cortex were significantly decreased in stressed-melatonin treated group compared with stressed group but were significantly increased compared with the other groups. These experiments indicate that its increase is inhibited by melatonin treatment even though, stress increases TH immunoreactivity in LC and Par.

The Effect of Melatonin Injection into Rat Brain Stem with Chronic Stress on Serotonergic Immunoreactivity / 체질인류학회지

These experiments were performed to investigate the effect of saline, melatonin, stress, stressed-melatonin on serotonin immunoreactivity in rat brain stem. The animals were injected with melatonin (1 mg/kg, i.p.) after electric shocks for 15days. The results were as follows; 1. Serotonin immunoreactive neurons in brain stem (the number of staining neuron & the stain intensity in dorsal raphe nucleus of midbrain, the stain intensity in nucleus tractus solitarius and dorsal raphe nucleus of vagus nerve in medulla oblongata) were decreased in melatonin treated group compared with all the other groups. 2. Serotonin immunoreactive neurons in brain stem (the number of staining neuron & the stain intensity in dorsal raphe nucleus of midbrain, the stain intensity in nucleus tractus solitarius and dorsal raphe nucleus of vagus nerve in medulla oblongata) were significantly increased in stressed group compared with all the other groups. 3. Serotonin immunoreactive neurons in brain stem(the number of staining neuron & the stain intensity in dorsal raphe nucleus of midbrain, the stain intensity in nucleus tractus solitarius and dorsal raphe nucleus of vagus nerve in medulla oblongata) were significantly decreased in stressed-melatonin treated group compared with only stressed group but were significantly increased compared with melatonin treated group. These experiments indicate that serotonin immunoreactive neurons in dorsal raphe nucleus of midbrain were increased, due to the activation of stress, and decreased when the activating of stress is suppressed through melatonin treatment.

Biological Analysis of a New Spontaneous Mutant Mouse Showing Deafness and Circling Behavior / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Deafness is the most common sensory deficit and hereditary defect in human populations. The present study investigated the causative gene in circling mice using the complementation test. In addition, the phenotypes and histopathologic findings in circler mice, spinner mice, and compound heterozygote mice were analyzed to elucidate the mechanism of causative gene in inner ear deafness. MATERIALS AND METHOD: In order to analyze inner ear pathology in time sequence for the circler mice, spinner mice, and compound heterozygote, five groups of the homozygous mutants of different ages were used: 10, 18, 21, 35, and 90 days old. The organs of Corti and spiral ganglion neurons in the basal and middle turns were included for quantification. For the preparation of genomic DNA, tail tissues were used. RESULTS: The hair cells in the organ of Corti degenerated in a time-dependent manner. In the basal and middle turns, the volume ratio of spiral ganglion neurons significantly decreased as the mutant aged. RT-PCR analysis indicated that transmembrane inner ear (Tmie) was absent in the case of circler mice, similar to spinner mouse of which is defective Tmie gene. Therefore the variations may be a result from strain-specific allelic differences of the Chr 9 Tmie gene itself (allelic heterogeneity). CONCLUSION: The cir mutant is a suitable mouse model for neuroepithelial defects. PCR and RT-PCR analyses suggest that the Tmie transcript is absent in circler mice. This model represents another candidate for human genetic hearing loss.

The Effect of Photoperiod and Melatonin Injection on Serotonergic Immunoreactivity in Rat Brain Stem / 대한해부학회지

These experiments were performed to investigate the effect of photoperiod and melatonin on serotonergic immunoreactivity in rat brain stem. The animals were injected with melatonin (1 mg/kg, i.p.) after light and dark treatment. The results by immunohistochemical method were as follows; 1. Immunohistochemical serotonin intensity in brain stem (dorsal raphe nucleus of midbrain, nucleus tractus solitarius and dorsal raphe nucleus of vagus nerve in medulla) appeard weakly in medium in control group compared with light and dark treated group. It suggest that enhanced effect in single injection (light or dark) was canceled by complex mechanism when two factors (light and dark) bring about together. 2. Serotonin immunoreactive neurons in brain stem (dorsal raphe nucleus of midbrain, nucleus tractus solitarius and dorsal raphe nucleus of vagus nerve in medulla) were significantly increased in light and dark treated group compared with control group. These results show that serotonin pathways are more important in mediating the effects of retinally perceived light in the rat. 3. Serotonin immunoreactive neurons in brain stem (dorsal raphe nucleus of midbrain, nucleus tractus solitarius and dorsal raphe nucleus of vagus nerve in medulla) were incresesed in melatonin treated group compared with melatonin non-treated group in light and dark. These results indicated that melatonin injection during photo and dark period enhanced serotonergic neurons activity and then light control influenced the development of serotonergic systems in brain stem including dorsal raphe nucleus of midbrain, nucleus tractus solitarius and dorsal nucleus of vagus nerve in medulla.

The Effect of Treatment with Tryptophan and/or Imipramine on the Serotonergic Immunoreactivity in Raphe Nucleus of Midbrain of the Rats / 대한해부학회지

These experiments were performed to investigate the effect of saline, tryptophan, tryptophan-imipramine and/or imipramine on serotonin immunoreactivity in raphe nucleus of midbrain of the rats (180~200 g, body weight). The animals were injected i.p. with tryptophan (15 mg/kg) and imipramine (15 mg/kg) for 20 days. The result by immunohistochemical methods were as follows; 1. Serotonin-immunoreactive neurons in the raphe of midbrain were significantly increased in tryptophan treated group compared to imipramine treated group. 2. Serotonin-immunoreactive neurons in the raphe of midbrain were decreased in imipramine treated group compared all the other group. 3. Serotonin-immunoreactive neurons in the raphe of midbrain were significantly decreased in tryptophanimipramine treated group compared to imipramine treated group. These experiments indicated that serotonin immunoreactive neurons in raphe of midbrain were increased due to the activation of tryptophan and decreased by suppresing activation of tryptophan through imipramine treatment.

The Effect of Treatment with Imipramine and/or Tryptophan after Chronic Stress on the Serotonergic Immunoreactivity in Rat Raphe Nucleus / 대한해부학회지

These experiments were performed to investigate the effect of saline, stress, imipramine, stress -imipramine and/or stress -tryptophan on serotonin immunoreactivity in raphe nucleus of the rats (200 ~220 g, body weight). The animals were injected i.p. with imipramine (15 mg/kg) and tryptophan (15 mg/kg) after electric shocks for 20 days. The result by immunohistochemical methods were as follows; 1. Serotonin -immunoreactive neurons in the raphe nucleus of midbrain were significantly increased in stress treated group compared to saline treated group. 2. Serotonin -immunoreactive neurons in the raphe nucleus of midbrain were decreased in imipramine treated group compared all the other group. 3. Serotonin -immunoreactive neurons in the raphe nucleus of midbrain were significantly decreased in stress -imipramine treated group compared to stress alone treated group but were significantly increased in stress -imipramine treated group compared to imipramine treated group. 4. Serotonin -immunoreactive neurons in the raphe nucleus of midbrain were significantly increased in stress -tryptophan treated group compared to stress alone and saline treated group. These experiments indicated that serotonin immunoreactive neurons in raphe nucleus of midbrain were increased due to the activation of stress and decreased by suppresing activation of stress through imipramine treatment.

The effect of treatment with tryptophan and/or reserpine on the serotonergic immunoreactivity in raphe nucleus of medulla oblongata and midbrain of the rats / 대한해부학회지

The present study was carried out to investigate the effect of treatment with tryptophan and/or reserpine on the raphe of medulla oblongata and mid brain of the rats (180~200 g body weight). the animal were injected i.p. with reserpine (5 mg/kg) for 3 days and tryptophan (15 mg/kg) for 20 days. The results by immunohistochemical methods were as follows: 1. Serotonin-immunoreactive neurons in the raphe of medulla oblongata and mid brain decrease in reserpine treated group compared to all the other group. 2. Serotonin-immunoreactive neurons in the raphe of medulla oblongata and mid brain were increased in tryptophan -reserpine treated group compared to the reserpine treated group but not the tryptophan treated group. 3. Serotonin-immunoreactive neurons in the raphe of medulla oblongata and mid brain were inceased in tryptophan treated group compared to all the other group. The experiments indicated that serotonin immunoreactive neurons in medulla oblongata and mid brain increased due to the activation of tryptophan and decreased by suppressing activation of tryptophan through reserpine.

The Effects on the MSG with Phenylalanine Treatment in the Area Postrema of the Rat Medulla / 체질인류학회지

Glutamate is an amino acid neurotransmitter capable of producing widespread receptor-mediated neuronal excitation. In this experiment, we examined the effect of saline, monosodium glutamate (MSG), phenylalanine and MSG-phenylalanine treatment on TH immunoreactivity in area postrema (AP) of medulla oblangata. An immunocytochemical method was used to visualize catecholaminergic neurons in the AP. Damage of TH neurons in the AP of adult Sprague-Dawley rats was induced by injection of MSG (4 mg/g bw) and was decreased by administration of MSG following phenylalanine treatment (15 mg/g bw). We conclude that phenylalanine protect from the neuroexcitotoxic effect of systemic glutamate.