ABSTRACT
This study was designed to clarify the cytotoxic effects of 5, 7-dihydroxytryptamine (5, 7-DHT) on the serotonergic neurons in the dorsal raphe nucleus, and to investigate the glial reaction during the neurodegenerative changes by light and electron microscopy. Adult male rats (Sprague-Dawley strain) weighing from 250 g to 350 g each were used as experimental animal. 5, 7-DHT (200 mg dissolved in 0.9% NaCl) was injected into the lateral ventricle of the rat brain with the Hamiton syringe fixed on stereotaxic apparatus. The control rats were given with the similar volume of 0.9% NaCl. The rats were sacrified on the 1st, 3rd, 5th, 10th and 20th day after the injection of 5, 7-DHT. The results were as follows : Glial reactions induced by 5, 7-DHT were also observed in DRN. In early experimental stage, microglial reactions prevailed, whereas astroglial reactions were prevailing in later stage. In addition, microglial cells phagocytosed and removed the degenerated cells. However, astrocytes in DRN did not show phagocytotic activities such as microglial cells. Based on the results, author thought that 5, 7-DHT act as a specific neurotoxin to serotonergic neurons in DRN, and induces severe neurodegenerative changes. The glial reactions in DRN are activated during the neurodegerative changes, and show characteristic patterns of glial reactions.
Subject(s)
Adult , Animals , Humans , Male , Rats , Astrocytes , Brain , Lateral Ventricles , Microglia , Microscopy, Electron , Neuroglia , Raphe Nuclei , Serotonergic Neurons , SyringesABSTRACT
This study was designed to clarify the cytotoxic effects of 5, 7-dihydroxytryptamine (5, 7-DHT) on the serotonergic neurons in the dorsal raphe nucleus, and to investigate the glial reaction during the neurodegenerative changes by light and electron microscopy. Adult male rats (Sprague-Dawley strain) weighing from 250 g to 350 g each were used as experimental animal. 5, 7-DHT (200 microgram dissolved in 0.9% NaCl) was injected into the lateral ventricle of the rat brain with the Hamiton syringe fixed on stereotaxic apparatus. The control rats were given with the similar volume of 0.9% NaCl. The rats were sacrified on the 1st, 3rd, 5th, 10th and 20th day after the injection of 5, 7-DHT. The results were as follows : The cytotoxicity of 5, 7-DHT resulted in severe neurodegenerations of the serotonergic neurons. Most degenerated cells mainly showed necrotic findings, but a few of them exhibited apoptotic features. That is, in early stage of this experiment, the degenerated cells showed edematic changes of cytoplasm, but their nuclei were relatively seen intact. In late stage, the cells showed dark degenerative changes both in their cytoplasm and nuclei. Thereafter the cells were autolysed or phagocytosed by neighboring glial cells. Based on the results, author thought that 5, 7-DHT act as a specific neurotoxin to serotonergic neurons in DRN, and induces severe neurodegenerative changes. The glial reactions in DRN are activated during the neurodegerative changes, and show characteristic patterns of glial reactions.
Subject(s)
Adult , Animals , Humans , Male , Rats , Brain , Cytoplasm , Lateral Ventricles , Microscopy, Electron , Neuroglia , Raphe Nuclei , Serotonergic Neurons , SyringesABSTRACT
The effects of dehydration on vasopressin and oxytocin immunoreactive neurons in the hypothalamus was investigated by using a immunohistochemistry. Adult Mongolian gerbil[Meriones unguiculates] were deprived of drinking water. Dehydrated animals were sacrificed on the 7th, 14th and 21st day of water retriction. The results are as follows : 1. The body weights were decreased about 1.8% daily. On the 21st day of dehydration, they were shown up to 45% compare to the control. 2. In the hypothalamus of the control group, majority of vasopressin and oxytocin immunoreactive neurons were located in the supraoptic and paraventricular nuclei. 3. Changes due to dehydrated stimulation were mainly observed in vasopressin immunoreactive neurons. And these changes in supraoptic nuclei were more severe than those in paraventricular nucleus. Size of vasopressin immunoreactived cells and of areas were increased as to proceed the dehydration. The numbers of those were increased on the 7th day of dehydration, and then they were continously decreased. 4. Although oxytocin immunoreactive neurons were slightly changed in numbers during dehydration, they were not shown conspicuous changes compare to vasopressin immunoreactive neurons. Thus it is appeared that vasopressin secretory neurons in the hypothalamus of Mongolian gerbil are affected by osmotic stress induced dehydration while oxytocin neurons may be affected by other factors.
Subject(s)
Adult , Animals , Humans , Body Weight , Dehydration , Drinking Water , Gerbillinae , Hypothalamus , Immunohistochemistry , Neurons , Osmotic Pressure , Oxytocin , Paraventricular Hypothalamic Nucleus , Supraoptic Nucleus , Vasopressins , WaterABSTRACT
The distribution and morphology of cholecystokinin-8 (CCK 8)-, neuropeptide Y (NPY)-, Substance P (SP)- and vasoactive intestinal polypeptide (VIP)-immunoreactivity were examined in the cat superior colliculus (SC) by means of immunohistochemistry. Judging from this study, some neuropeptides-IR neurons may be present in the superficial layers of the sc. And these neurons and neuropeptides may be involved in the functions of the superficial layers.
Subject(s)
Animals , Cats , Brain , Immunohistochemistry , Neurons , Neuropeptide Y , Neuropeptides , Substance P , Superior Colliculi , Vasoactive Intestinal PeptideABSTRACT
No abstract available.
Subject(s)
Animals , Rats , Brain , Corpus Striatum , Neurons , NeuropeptidesABSTRACT
No abstract available.
Subject(s)
Animals , Rats , Adrenocorticotropic Hormone , Hypothalamus , NeuronsABSTRACT
No abstract available.