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Crcadian and ultradian rhythms of superoxide dismutase in the pineal gland
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The following issues are raised in this study: 1. The reciprocal interrelation between the peripheral and central noradrenergic system. There is evidence that increased sympathetic activity inhibits the noradrenergic brain stem system which modulates the thresholds for thermoregulatory heat production (Szel6nyi et al., 1977; Briick and Zeisberger, 1987). 2. The role of central noradrenergic thermosensifive and thermointegrative structures in the regulation of heat production after peripheral or central treatment with NA. References BrOck, K., Zeisberger, E., 1987, Adaptive changes in thermoregulation and their neuropharmacological basis, Pharmac. Ther. 35, 163. Sze|6nyi, Z., Zeisberger, E., BrOck, K., 1977, A hypothalamic alpha- adrenergic mechanism mediating the thermogenic response to electrical stimulation of the lower brainstem in the guinea pig, Pfliigers Arch., 370, 19.
IP.we.0221 Orcadian and uRradian rhythms of uperoxide d|smutase in the pineal gland Neto, J.C., Abdalla *, D.S.P., Markus, R.P., da Gra~2a N. Mazzaconatti * *, M. and Campa *, A. Instituto de Ci~.ncias Biom#dicas da Unioersidade de S~o Paulo, S.P., C.P. 05508, * Faculdade de Ci#ncias Farmac~.uticas da Universidade de S~o Paulo, S.P., C.P. 30. 768 and * * Escola Paulista de Medicina, S.P., CEP, 04023, Brazil
Superoxide dismutase (SOD) (E.C.I.15.1.1) is part of the enzymatic system which counteracts reactive oxygen species. In brain tissues, these enzymes provide protection against membrane lipid peroxidation and biogenic amine oxidation. It is known that the pineal gland shows a high oxidative metabolism relative to synthesis and degradation of monoamines and it is an organ that contains high concentrations of easily oxidable substances including indolanfines and catecolamines. The mammalian pineal gland, an essentially endocrine organ whose main hormone, melatonin, is important in the control of the biological rhythms of the organism, has almost all of its metabolic processes temporally organized throughout the 24 hour day. The aim of this work was to study the temporal profile of total SOD activity (Cu-Zn-SOD and Idn-SOD) in the pineal gland and its possible relationship to the circadian rhythm of serotonin concentration. Three-month-old male Wistar albino rats were deeply anaesthetised with ether and perfused through the left ventricle with ice cold saline. The pineal glands were rapidly removed and stored at - 2 0 ° C until assayed. SOD activity was measured by the nitrite method and serotonin using HPLC with an electrochemical detector. The randomized block design analysis of variance (4 experimental 24-hour blocks; 24 rats per block; 3 rats each 3 hour; n = 116) showed a significant hour of the day effect (p = 0.009) in SOD activity.Rhythmic analysis (best-fitting cosine curve tested for zero amplitude) showed a significant 24-hour rhythm (p < 0.001) with a maximal SOD activity at 14:26 h 5:0:42 h, a mean 24 h value of 37.78 5:0.87 U SOD (nitrite) per mg of protein; and an amplitude of oscillation of 8% of the 24 h mean. In addition to the circadian rhythm, an ultradian rhythm of 9 hour was detected (p < 0.001) with a higher peak at 13:19 h and a lower one at 22:19 h. The total concentration of serotomn in the gland shev,'~ ~ c~rcad;,a.n rhythm (p = 0.002) with maximal value at 12:26 5:0:31 h. The daily maximal total SOD activity seems to be related to the well kwown profile reported for the pineal gland content of ser,t9~in and other metabolites such as 5-hydroxy and 5-methoxy derivatives of indolacetic acid and thyptophol (Meffo:d et al., 1983). Furthermore, the ultradian peaks obtained seem to be temporally coincident to maximal concentrations of serotonin (day) and noradrenaline (night). These data emphasize the proposed correlation between tot~ SOD activity and bioge=fic arair~e concentrations (Thomas, 1976). Supported by FAPESP and CNPq. References Mefford, I.N. et al. (1983) Endocrinology 113, 1582. Thomas, T.N. et al. (1976) J. Neurochem. 27, 309.
The following issues are raised in this study: 1. The reciprocal interrelation between the peripheral and central noradrenergic system. There is evidence that increased sympathetic activity inhibits the noradrenergic brain stem system which modulates the thresholds for thermoregulatory heat production (Szel6nyi et al., 1977; Briick and Zeisberger, 1987). 2. The role of central noradrenergic thermosensifive and thermointegrative structures in the regulation of heat production after peripheral or central treatment with NA. References BrOck, K., Zeisberger, E., 1987, Adaptive changes in thermoregulation and their neuropharmacological basis, Pharmac. Ther. 35, 163. Sze|6nyi, Z., Zeisberger, E., BrOck, K., 1977, A hypothalamic alpha- adrenergic mechanism mediating the thermogenic response to electrical stimulation of the lower brainstem in the guinea pig, Pfliigers Arch., 370, 19.
IP.we.0221 Orcadian and uRradian rhythms of uperoxide d|smutase in the pineal gland Neto, J.C., Abdalla *, D.S.P., Markus, R.P., da Gra~2a N. Mazzaconatti * *, M. and Campa *, A. Instituto de Ci~.ncias Biom#dicas da Unioersidade de S~o Paulo, S.P., C.P. 05508, * Faculdade de Ci#ncias Farmac~.uticas da Universidade de S~o Paulo, S.P., C.P. 30. 768 and * * Escola Paulista de Medicina, S.P., CEP, 04023, Brazil
Superoxide dismutase (SOD) (E.C.I.15.1.1) is part of the enzymatic system which counteracts reactive oxygen species. In brain tissues, these enzymes provide protection against membrane lipid peroxidation and biogenic amine oxidation. It is known that the pineal gland shows a high oxidative metabolism relative to synthesis and degradation of monoamines and it is an organ that contains high concentrations of easily oxidable substances including indolanfines and catecolamines. The mammalian pineal gland, an essentially endocrine organ whose main hormone, melatonin, is important in the control of the biological rhythms of the organism, has almost all of its metabolic processes temporally organized throughout the 24 hour day. The aim of this work was to study the temporal profile of total SOD activity (Cu-Zn-SOD and Idn-SOD) in the pineal gland and its possible relationship to the circadian rhythm of serotonin concentration. Three-month-old male Wistar albino rats were deeply anaesthetised with ether and perfused through the left ventricle with ice cold saline. The pineal glands were rapidly removed and stored at - 2 0 ° C until assayed. SOD activity was measured by the nitrite method and serotonin using HPLC with an electrochemical detector. The randomized block design analysis of variance (4 experimental 24-hour blocks; 24 rats per block; 3 rats each 3 hour; n = 116) showed a significant hour of the day effect (p = 0.009) in SOD activity.Rhythmic analysis (best-fitting cosine curve tested for zero amplitude) showed a significant 24-hour rhythm (p < 0.001) with a maximal SOD activity at 14:26 h 5:0:42 h, a mean 24 h value of 37.78 5:0.87 U SOD (nitrite) per mg of protein; and an amplitude of oscillation of 8% of the 24 h mean. In addition to the circadian rhythm, an ultradian rhythm of 9 hour was detected (p < 0.001) with a higher peak at 13:19 h and a lower one at 22:19 h. The total concentration of serotomn in the gland shev,'~ ~ c~rcad;,a.n rhythm (p = 0.002) with maximal value at 12:26 5:0:31 h. The daily maximal total SOD activity seems to be related to the well kwown profile reported for the pineal gland content of ser,t9~in and other metabolites such as 5-hydroxy and 5-methoxy derivatives of indolacetic acid and thyptophol (Meffo:d et al., 1983). Furthermore, the ultradian peaks obtained seem to be temporally coincident to maximal concentrations of serotonin (day) and noradrenaline (night). These data emphasize the proposed correlation between tot~ SOD activity and bioge=fic arair~e concentrations (Thomas, 1976). Supported by FAPESP and CNPq. References Mefford, I.N. et al. (1983) Endocrinology 113, 1582. Thomas, T.N. et al. (1976) J. Neurochem. 27, 309.