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Zn-SOD in cells at the injection site
S89
EFFECTS OF CORTICOSTEROIDS ON THE MORPHOLOGY AND FUNCTION OF MICROGLIA. *TUNYA TANAKA, HIROKO FUTITA, MASAHIRO SAKANAKA, *NOBUJI MAEDA. Dept. of *Physiol. and Anatom., Ehime. Univ. Sch. of Med., Ship;enobu, Onsen-gun, Ehime, 791-02, Iapan
730
The effects of steroid hormons on cultured rat microglial cells were investigated. Corticosterone, cortisol, dexamethasone and aldosterone caused significant shrinkage of microglial cell bodies in the presence of serum. The values of ED 50 for individual steroids were I-1OnM. A higher concentration of progesterone (100nM) showed a similar effect. Cholesterol, pregnenolone, testosterone, estradiol and dihydroepiandrosterone did not exhibit any significant effects at a dose of 100 nM. Corticosteroids also inhibited the GM-CSF-mediated process extension of microglia. An anti-glucocorticoid agent completely reversed the effects of the glucocorticoids on microglial shape. Aldosterone also inhibited the GM-CSFmediated shape change, and its inhibitory effect was partially noted even in the presence of the antiglucocorticoid agent. NO synthesis stimulated by lipopolysaccharide and interferon-y was suppressed by glucocorticoids at concentrations higher than 1nM. Aldosterone, on the contrary, slightly stimulated NO synthesis at concentrations between 0.1 and 5 nM, while it inhibited NO synthesis at concentrations higher than 10 nM. These results suggest that the morphology and function of microglia may be regulated by physiological concentartions of corticosteroids and that microglial cells express both glucocorticoid and mineralocorticoid receptors.
731
IMMUNOCYTOCHEMICAL LOCALIZATION NERVOUS SYSTEM. HIROMICHI YOKOI.
ISHIMURA.
1st. Dept. of
OF 5x-REDUCTASE IN THE RAT PERIPHERAL YOSHIHIRO TSURUO AND KAZUNORI
Anat.. TokushimaUniv. Sch. of Med.. Kuramoto. Tokushima.770. Japan.
Steroid Sa-reductase is the enzyme that converts steroids with the C-4,5 double bond to their %x-reduced and the C-3 ketone (i.e. androgens, progestagens, and glucocorticoids) metabolites. In the rat brain the enzyme activity is high in the white matter and peaks in the first two weeks of life, and hence the enzyme is suggested to be involved in the myelin formation. In the peripheral nervous system, the enzyme activity is detected in the sciatic We made a rabbit polyclonal nerves, but the localization of the enzyme is not elucidated. antibody against rat 5o?-reductase type 1 and studied immunocytochemically the localization of 5a-reductase-immunoreactivity in the rat peripheral nervous system. The immunoreaction was detected in the satellite cells of the trigeminal ganglion and the Schwann cells of the sciatic nerves. In the Schwann cells the immunoreactivity was localized in the perikarya, outer loop and Schmidt-Lanterman incisure.
732 AKIRA
INJECTION SOD IN TOKUNAGA.
OF FeCl3 INTO THE RAT CORTEX CELLS AT THE INJECTION SITE. Dept. of Anat., Okayama Univ. Med. School.,
INDUCES MnAND Cu/ZnWANG YAN, KIMIKO TSUTSUI, Okayama, 700, Japan.
It is well known that formation of oxygen free radicals occurs soon after the FeCls injection into the cerebral cortex. As a protective response superoxide dismutases (SODS), one of antioxidant enzymes, have been reported to increase their activities at the injection site. Detailed analysis of the SODS after the injection, however, remains to be studied. We investigated 1) detailed time course of each isoform of SODS, Mn-SOD and Cu/Zn-SOD, from as early as 30 min through 4 w after the injection, 2) effects of an inhibitor of protein synthesis on the time courses, by means of immunohistochemistry using polyclonal antibodies specific to each enzyme. We observed a remarkable increase in number of Mn-SOD immunoreactive cells per unit area as early as 30 min after the injection which remained increased for 2 hr then leveled off. The increase observed once more at 2 to 3 days of injection. The first peak disappeared when rats were pretreated with cycloheximide, an inhibitor of protein synthesis, suggesting that the increase of Mn-SOD positive cells requires de nova enzyme synthesis. FeCls injection induced also an increase in the Cu/Zn-SOD immunoreactive cells, but the onset of the increase occurred only after 6 hr of injection which remained increased for about 2 days. These results clearly suggest that the induction of these isozymes by FeCl3 occurs through different mechanisms.
EFFECTS OF CORTICOSTEROIDS ON THE MORPHOLOGY AND FUNCTION OF MICROGLIA. *TUNYA TANAKA, HIROKO FUTITA, MASAHIRO SAKANAKA, *NOBUJI MAEDA. Dept. of *Physiol. and Anatom., Ehime. Univ. Sch. of Med., Ship;enobu, Onsen-gun, Ehime, 791-02, Iapan
730
The effects of steroid hormons on cultured rat microglial cells were investigated. Corticosterone, cortisol, dexamethasone and aldosterone caused significant shrinkage of microglial cell bodies in the presence of serum. The values of ED 50 for individual steroids were I-1OnM. A higher concentration of progesterone (100nM) showed a similar effect. Cholesterol, pregnenolone, testosterone, estradiol and dihydroepiandrosterone did not exhibit any significant effects at a dose of 100 nM. Corticosteroids also inhibited the GM-CSF-mediated process extension of microglia. An anti-glucocorticoid agent completely reversed the effects of the glucocorticoids on microglial shape. Aldosterone also inhibited the GM-CSFmediated shape change, and its inhibitory effect was partially noted even in the presence of the antiglucocorticoid agent. NO synthesis stimulated by lipopolysaccharide and interferon-y was suppressed by glucocorticoids at concentrations higher than 1nM. Aldosterone, on the contrary, slightly stimulated NO synthesis at concentrations between 0.1 and 5 nM, while it inhibited NO synthesis at concentrations higher than 10 nM. These results suggest that the morphology and function of microglia may be regulated by physiological concentartions of corticosteroids and that microglial cells express both glucocorticoid and mineralocorticoid receptors.
731
IMMUNOCYTOCHEMICAL LOCALIZATION NERVOUS SYSTEM. HIROMICHI YOKOI.
ISHIMURA.
1st. Dept. of
OF 5x-REDUCTASE IN THE RAT PERIPHERAL YOSHIHIRO TSURUO AND KAZUNORI
Anat.. TokushimaUniv. Sch. of Med.. Kuramoto. Tokushima.770. Japan.
Steroid Sa-reductase is the enzyme that converts steroids with the C-4,5 double bond to their %x-reduced and the C-3 ketone (i.e. androgens, progestagens, and glucocorticoids) metabolites. In the rat brain the enzyme activity is high in the white matter and peaks in the first two weeks of life, and hence the enzyme is suggested to be involved in the myelin formation. In the peripheral nervous system, the enzyme activity is detected in the sciatic We made a rabbit polyclonal nerves, but the localization of the enzyme is not elucidated. antibody against rat 5o?-reductase type 1 and studied immunocytochemically the localization of 5a-reductase-immunoreactivity in the rat peripheral nervous system. The immunoreaction was detected in the satellite cells of the trigeminal ganglion and the Schwann cells of the sciatic nerves. In the Schwann cells the immunoreactivity was localized in the perikarya, outer loop and Schmidt-Lanterman incisure.
732 AKIRA
INJECTION SOD IN TOKUNAGA.
OF FeCl3 INTO THE RAT CORTEX CELLS AT THE INJECTION SITE. Dept. of Anat., Okayama Univ. Med. School.,
INDUCES MnAND Cu/ZnWANG YAN, KIMIKO TSUTSUI, Okayama, 700, Japan.
It is well known that formation of oxygen free radicals occurs soon after the FeCls injection into the cerebral cortex. As a protective response superoxide dismutases (SODS), one of antioxidant enzymes, have been reported to increase their activities at the injection site. Detailed analysis of the SODS after the injection, however, remains to be studied. We investigated 1) detailed time course of each isoform of SODS, Mn-SOD and Cu/Zn-SOD, from as early as 30 min through 4 w after the injection, 2) effects of an inhibitor of protein synthesis on the time courses, by means of immunohistochemistry using polyclonal antibodies specific to each enzyme. We observed a remarkable increase in number of Mn-SOD immunoreactive cells per unit area as early as 30 min after the injection which remained increased for 2 hr then leveled off. The increase observed once more at 2 to 3 days of injection. The first peak disappeared when rats were pretreated with cycloheximide, an inhibitor of protein synthesis, suggesting that the increase of Mn-SOD positive cells requires de nova enzyme synthesis. FeCls injection induced also an increase in the Cu/Zn-SOD immunoreactive cells, but the onset of the increase occurred only after 6 hr of injection which remained increased for about 2 days. These results clearly suggest that the induction of these isozymes by FeCl3 occurs through different mechanisms.