The Role of Endothelin Receptor A during Myelination of Developing Oligodendrocytes

Endothelin (ET)-1 and its receptors (ETA and ETB receptor) are present in the central nervous system. ET exerts biological effects on gliogenesis and glial cell functions. In order to define a possible mechanism of ETA receptor signaling, the distribution of the ETA receptor in developing oligodendrocytes and the effects of ET-1 on the myelination of oligodendrocytes were examined. ETA receptor immunoreactivity was confined to the perivascular elements of the blood vessels during early postnatal development. However later in development, ETA receptor immunoreactivity was no longer observed in the vessels but became localized to the myelinating oligodendrocytes of the primitive corpus callosum of the white matter, apart from the vessels. ET-1 induced myelin basic protein (MBP) in primary oligodendrocyte precursor cell culture though the ETA receptor and was blocked by an ETA receptor antagonist. In addition, ET-1 evoked the release of Ca2+ which is a central regulator of oligodendrocyte differentiation. Our results provide a link between ET-1 and its ETA receptor and myelination during oligodendrocyte differentiation.

17beta-estradiol Attenuates Renal Fibrosis in Mice with Obstructive Uropathy

PURPOSE: Men are generally more prone to chronic renal disease and progression to end stage renal disease than women. The purpose of this study is to prove the effect of gender and sex hormone on renal fibrosis in mice with unilateral ureteral obstruction (UUO) and to elucidate the specific underlying mechanisms. METHODS: We compared the expression of alpha-smooth muscle actin (alpha-SMA) in female and male mice with complete UUO (day 7). After this, we estimated the changes of renal fibrosis in the female mice with oophorectomy and in the female mice with oophorectomy and replacement of 17beta-estradiol, respectively. RESULTS: The level of alpha-SMA in the female kidney with UUO was significantly lower than that in the male kidney with UUO. oophorectomy and replacement of 17beta-estradiol did not change the expression of angiotensin II type 1 (AT1) receptor in the female kidney with UUO, whereas the expression of angiotensin II type 2 (AT2) receptor was significantly more elevated in the intact female (IF) and the oophorectomized female with estrogen (OF+E) than that in the oophorectomized female (OF). The expressions of inducible nitric oxide synthase (iNOS) in the IF and OF+E mice were significantly more elevated than that in the OF mice, which was similar to the expression of AT2 receptor. CONCLUSION: The female gender is associated with resistance to renal fibrosis in obstructive uropathy and this gender difference may originate from the existence of 17beta-estradiol, which has an anti-fibrotic effect via upregulation of the AT2 receptor and iNOS.

Comparative study on muscle activities of pre-and post-orthognathic surgery in skeletal Class III malocclusion patients and normal group / 대한치과교정학회지

Craniofacial region is a musculodentoskeletal system that consists of many anatomical structures ; cranioskeletal structures, dental arches, and formation and functions of masticatory muscles have close correlations. Growth and development of craniofacial region are influenced by not only hereditory factors, but also environmental factors such as craniofacial muscles and surrounding tissues. On the contrary, however, study on changes in functions or adaptations of craniofacial muscles following changes of craniofacial skeletal structures has been somewhat insufficient. The author's purpose was to observe correlations between masticatory muscular functions and change patterns according to cranial skeletal structures and occlusion patterns ; for this, comparative study of muscle activity changes of preand post- orthognathic surgery states in skeletal Cl III malocclusion patients was performed. The selected sample groups were 15 normal male patients, 15 skeletal CI Ill pre-orthognatic surgery patients and 15 skeletal CI Ill post-orthognatic surgery patients. For each sample groups, cephalometric x-ray taking, masticatory efficiency test and measurements of muscle activities in anterior temporal muscle, masseter and upper lip in rest, clenching, chewing and swallowing were carried out. The following results were obtained: 1. In resting state of mandible, pre-surgery malocclusion group showed higher m activities in ant. temporalis, masseter and upper lip than post-surgery group. Post-surg, malocc. group showed significantly high m. activity only in upper lip compared to the normal group. 2. In clenching state, post-surg. malocc. group showed higher m. activities in ant. temporalis, masseter and upper lip than pre-surg. malocc. group. 3. In chewing state, post-surg. malocc. group showed higher m. activities in ant. temporalis and masseter than pre-surg, malocc. group ; on the other hand, decreased upper lip activity was noticed. 4. In swallowing state, post-surg, malocc. group showed lower upper lip activity than pre-surg. malocc. group but higher than that of the normal group. No significant difference in m. activities of ant. temporalis and masseter was noticed among the three groups. 5. Masticatory efficiency was lower in pre-surg, malocc. group than normal group; masticatory efficiency showed an increase in post-surg. malocc. group compared to the pre-surg. malocc. group. However, both groups showed significant differences compared to the normal group.