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Tokumura A, Asai T, Takauchi K, Kamiyasu K, Ogawa T, Tsukatani H. Novel phospholipids with aliphatic dicarboxylic acid residues in a lipid extract from bovine brain. Biochem Biophys Res Commun 1988; 155:863-9. [PMID: 3421972 DOI: 10.1016/s0006-291x(88)80575-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A vasodepressor phospholipid fraction purified from a lipid extract of bovine brain was found to contain novel phospholipids with both a long-chain acyl group and an aliphatic dicarboxylic acid residue. This was shown by analyzing the fraction as tert-butyldimethylsilyl derivatives of glyceride by capillary GC-MS after hydrolysis with phospholipase C. Six molecular species with a palmitoyl group and an aliphatic dicarboxylate (chain length C4-C9), and two species with both a stearoyl group and a succinate or glutarate residue were detected.
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Tokumura A, Terao M, Okamoto M, Yoshida K, Tsukatani H. Study of platelet activating factor and its antagonists on rat colon strip with a new method avoiding tachyphylaxis. Eur J Pharmacol 1988; 148:353-60. [PMID: 3384001 DOI: 10.1016/0014-2999(88)90113-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Platelet activating factor induced slow, but sustained contraction of isolated rat colon in a dose-dependent manner. The contraction persisted even when the strips were washed several times with Tyrode solution. However, the addition of high concentrations of bovine serum albumin to the washing solution led to the rapid relaxation of the strips to the basal level, possibly by removing platelet activating factor tightly bound to rat colon. These strips then responded normally to a second addition of platelet activating factor. Neither the cholinergic nervous system nor release of histamine, serotonin, prostaglandins or leukotriene D4 were significantly involved in the contraction induced by platelet activating factor. FR-900452 and CV-3988, recently found to be antagonists of platelet activating factor, selectively blocked the contraction of rat colon induced by the active phospholipid, indicating that it induced contraction by a direct stimulatory effect on the smooth muscle of rat colon in a receptor-mediated manner.
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Fukuzawa K, Kishikawa K, Tadokoro T, Tokumura A, Tsukatani H, Gebicki JM. The effects of alpha-tocopherol on site-specific lipid peroxidation induced by iron in charged micelles. Arch Biochem Biophys 1988; 260:153-60. [PMID: 3341738 DOI: 10.1016/0003-9861(88)90436-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
alpha-Tocopherol inhibited H2O2-Fe2+-induced lipid peroxidation of linoleic acid (LA) by scavenging OH radicals in tetradecyltrimethylammonium bromide (TTAB) micelles. The inhibiting ability of alpha-tocopherol was much greater than that of OH-radical scavengers mannitol and t-butanol. In contrast, alpha-tocopherol enhanced linoleic acid hydroperoxide (LOOH)-Fe2+-induced lipid peroxidation through regeneration of Fe2+ in sodium dodecyl sulfate (SDS) micelles containing LA. alpha-Tocopherol was oxidized by Fenton's reagent (FeSO4 + H2O2) at a higher rate in SDS micelles than in TTAB micelles. The likely oxidants were OH radicals in the former and Fe3+ in the latter. Both reagents formed in the Fenton reaction. Ferrous ion catalyzed in a dose-dependent manner the decomposition of LOOH and conjugated diene compounds in SDS but not in TTAB micelles. alpha-Tocopherol and Fe3+ individually had no effect on the decomposition of LOOH, but together were quite effective. The rate of the decomposition was a function of the concentration of alpha-tocopherol. The mechanism of "site-specific" antioxidant action of alpha-tocopherol in charged micelles is discussed.
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Tokumura A, Kamiyasu K, Takauchi K, Tsukatani H. Evidence for existence of various homologues and analogues of platelet activating factor in a lipid extract of bovine brain. Biochem Biophys Res Commun 1987; 145:415-25. [PMID: 3593346 DOI: 10.1016/0006-291x(87)91338-6] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Vasodepressor phospholipid with platelet-aggregating activity was highly purified from a lipid extract of bovine brain and subjected to field desorption-mass spectrometry. It was further analyzed by gas-liquid chromatography-mass spectrometry after hydrolysis with phospholipase C and conversion to tert-butyldimethylsilyl derivatives. Results indicated the presence of four species of platelet activating factor (1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine, PAF) and ten acyl analogues of PAF. The acyl analogues of PAF included species having an sn-2-propionyl or sn-2-butyryl group, which have not been previously detected in natural sources. The total amount of acyl analogues of PAF was much higher than that of PAF.
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Tokumura A, Yoshida J, Okasaka N, Fukuzawa K, Tsukatani H. Platelet aggregation induced by ether-linked phospholipids. 2. Mechanism of desensitization of rabbit platelets by platelet activating factor and reversibility of inhibitory actions of its antagonists. Thromb Res 1987; 46:153-61. [PMID: 3590110 DOI: 10.1016/0049-3848(87)90215-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Rabbit platelets pretreated with CV-3988 had reduced responsiveness to platelet activating factor(PAF) even after the platelets had been washed with a buffer. This was due to its tight binding to receptor sites for PAF, but not conformational changes of the receptor, because the platelets that were pretreated with CV-3988 and then washed with buffer containing 0.5% bovine serum albumin showed full responsiveness to PAF. In contrast, the reduced responsiveness of PAF-pretreated rabbit platelets was not reversed by washing with buffer containing 0.5% BSA. The PAF-pretreated platelets showed significantly lower responsiveness to 1-O-hexadecyl-2-O-monomethylaminocarbonyl-sn-glycero-3-phosphochol ine (MC-PAF) than to PAF, although MC-PAF had the same potency as PAF on inducing aggregation of normal rabbit platelets by interacting with receptor sites for PAF. These results suggest that the desensitization is accompanied by a decreased affinity of receptor sites for PAF or reduced efficiency in coupling of activated receptor to regulatory protein in plasma membranes rather than loss of receptor sites.
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Tokumura A, Yoshida J, Maruyama T, Fukuzawa K, Tsukatani H. Platelet aggregation induced by ether-linked phospholipids. 1. Inhibitory actions of bovine serum albumin and structural analogues of platelet activating factor. Thromb Res 1987; 46:51-63. [PMID: 3647677 DOI: 10.1016/0049-3848(87)90206-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Ether-linked lysophosphatidic acid was able to induce aggregation of platelets from various animals. Feline platelets were the most sensitive followed in decreasing order by human, bovine and rabbit platelets. ONO-6240 and CV-3988, which are antagonists of platelet activating factor, did not inhibit aggregation of feline platelets induced by ether-linked lysophosphatidic acid, indicating that the aggregation induced by the lysophosphatidic acid did not involve receptors for platelet activating factor. An addition of bovine serum albumin caused dose-dependent inhibitions on the aggregation of platelets by both ether-linked lysophosphatidic acid and platelet activating factor. Moreover, 0.5% bovine serum albumin reversed platelet aggregation by the active phospholipid before this aggregation reached a maximum. These results suggest that the lysophosphatidic acid exerts its stimulatory action extracellularly, probably by interacting with specific sites on the surface of platelet.
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Yoshida J, Tokumura A, Fukuzawa K, Terao M, Takauchi K, Tsukatani H. A platelet-aggregating and hypotensive phospholipid isolated from bovine brain. J Pharm Pharmacol 1986; 38:878-82. [PMID: 2880959 DOI: 10.1111/j.2042-7158.1986.tb03375.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A phospholipid that differs from known active lipids and causes potent platelet aggregation and weak hypotension has been isolated from bovine brain. Its platelet aggregating effect on heparinized platelet-rich plasma from rabbits, was at a threshold concentration of about 0.2 nmol ml-1 as phosphorus. The effect was inhibited by CV-3988. The phospholipid was converted by diazomethane treatment to another active lipid that caused short-term hypotension, but not platelet aggregation, rather it inhibited the aggregation of rabbit heparinized platelets induced by platelet-activating factor.
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Tokumura A, Harada K, Fukuzawa K, Tsukatani H. Involvement of lysophospholipase D in the production of lysophosphatidic acid in rat plasma. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 875:31-8. [PMID: 3632787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A vasoactive lipid present in rat plasma that had been incubated at 37 degrees C for 48 h was identified as lysophosphatidic acid with the following fatty acid composition: palmitic acid (25.2%), stearic acid (8.4%), oleic acid (7.0%), linoleic acid (44.4%) and arachidonic acid (11.9%). The involvement of lysophospholipase D in the production of lysophosphatidic acid was suggested on the basis of extensive analyses of phospholipids in the plasma. Results indicated that lysophospholipase D hydrolyzed polyunsaturated lysophosphatidylcholines preferentially to the saturated species. Exogenously added platelet activating factor was found to be first converted to its lyso derivative by an acetylhydrolase in rat plasma and then degraded by lysophospholipase D to 1-alkyllysophosphatidic acid to a similar extent with exogenously added lyso derivative of platelet activating factor; their percent conversions to lysophosphatidic acid were higher than those of saturated 1-acyllysophosphatidylcholines, but lower than those of polyunsaturated 1-acyllysophosphatidylcholines.
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Fukuzawa K, Kishikawa K, Tokumura A, Tsukatani H, Shibuya M. Fluorescent pigments by covalent binding of lipid peroxidation by-products to protein and amino acids. Lipids 1985; 20:854-61. [PMID: 4094516 DOI: 10.1007/bf02534768] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The fluorescent products formed on reaction of 12-oxo-cis-9-octadecenoic acid (12-keto-oleic acid) with about 20 different amino acids, polylysine and bovine serum albumin (BSA) were studied. Besides glycine, only the basic amino acids histidine, lysine and arginine gave products with strong fluorescence. N-Acetylation of amino acids greatly reduced the fluorescence of their reaction products. The formation of fluorescent products was inhibited strongly by SH-amino acids such as N-acetyl-cysteine and glutathione. Polyacrylamide gel electrophoresis showed that BSA treated with 12-keto-oleic acid was more acidic than untreated or ricinoleic acid-treated BSA, indicating that basic amino acid residues in BSA were modified by reaction with the keto fatty acid. None of the structural analogs of 12-keto-oleic acid tested--12-oxo-trans-10-octadecenoic acid, 12-oxo-octadecanoic acid, 12-hydroxy-cis-9-octadecenoic acid (ricinoleic acid), cis-9-octadecenoic acid (oleic acid) and linoleic acid--reacted with glycine to give a fluorescent product. The fluorescent products formed on reaction of 12-keto-oleic acid methyl ester with benzyl amine and glycine methyl ester were shown to be 8-(N-substituted-4,5-dihydro-4-oxo-5-hexyl-5-hydroxy-2-pyrrolyl) octanoic acid methyl esters. The fluorescence properties of these compounds were attributed to the chromophobic system NC = CC = O which contains 6 pi electrons. This investigation contributes to insight of the mechanism of formation of fluorescent pigments, probably by a similar reaction of other compounds of the beta, gamma-unsaturated carbonyl type.
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Tokumura A, Tsukatani H. [Antagonists of platelet activating factor]. SEIKAGAKU. THE JOURNAL OF JAPANESE BIOCHEMICAL SOCIETY 1985; 57:1618-23. [PMID: 3009656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Tokumura A, Suzuki T, Takauchi K, Tsukatani H. Gas chromatographic-mass spectrometric analysis of biologically active phospholipids having an sn-2-acetyl group. JOURNAL OF CHROMATOGRAPHY 1985; 343:138-42. [PMID: 4066848 DOI: 10.1016/s0378-4347(00)84576-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Fukuzawa K, Takase S, Tsukatani H. The effect of concentration on the antioxidant effectiveness of alpha-tocopherol in lipid peroxidation induced by superoxide free radicals. Arch Biochem Biophys 1985; 240:117-20. [PMID: 2990339 DOI: 10.1016/0003-9861(85)90013-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Egg yolk phosphatidylcholine liposomes were rapidly oxidized in the presence of chelated iron and a superoxide-generating system. alpha-Tocopherol incorporated in the bilayer was oxidized at the same time. No lipid or alpha-tocopherol oxidation occurred in liposomes composed of dimyristoyl phosphatidylcholine. The antioxidant did not inhibit lipid peroxidation until its concentration reached a critical level, which depended on the effectiveness of the oxidative stress. Beyond this level, peroxidation was inhibited completely and, simultaneously, the rate of oxidation of tocopherol was lowered. The results suggest that the antioxidant efficiency of alpha-tocopherol depends on its ability to react mainly with the chain-initiating or chain-propagating lipid radicals. This, in turn, is closely tied to the tocopherol content of the membrane. Ascorbate inhibited the consumption of alpha-tocopherol, possibly by regenerating its reduced form.
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Takauchi K, Tokumura A, Yoshida J, Iwama T, Handa Y, Tatsumichi H, Tsukatani H. Identification of steroidal compounds as acetates in a lysate of "Depressor-I," an antihypertensive phospholipid occurring in acetone-soluble fraction of bovine brain. Chem Pharm Bull (Tokyo) 1985; 33:1334-41. [PMID: 4042217 DOI: 10.1248/cpb.33.1334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Tsukatani H, Takauchi K, Yoshida J, Yamada S, Tokumura A, Hamaguchi C. Isolation of diosgenin[(25R)-spirost-5-en-3 beta-ol] from a lysate of a new hypotensive phospholipid occurring in bovine brain. J Neurochem 1985; 44:658-61. [PMID: 3965623 DOI: 10.1111/j.1471-4159.1985.tb05463.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Diosgenin[(25R)-spirost-5-en-3 beta-ol] and cholesterol were detected as trimethylsilyl derivatives by gas chromatography-mass spectrometry in an alkaline lysate of a new hypotensive phospholipid from the lipid fraction of bovine brain. These steroids seemed to be present in the hypotensive phospholipid fraction in some bound forms.
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Takauchi K, Konishi M, Nomura M, Yoshida J, Fujii M, Handa Y, Tsukatani H. Phosphorus-free antihypertensive lipid from dog peritoneal dialysate, Peritoneal Dialysate Depressor-II. JOURNAL OF PHARMACOBIO-DYNAMICS 1984; 7:577-85. [PMID: 6512679 DOI: 10.1248/bpb1978.7.577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A phosphorus-free lipid with a transient antihypertensive effect was found in a dog peritoneal dialysate by a modified procedure. On silicic acid chromatography of the crude extract, a new hypotensive factor and a new hypertensive factor were separated besides the known antihypertensive phospholipid resembling lysolecithin (Peritoneal dialysate depressor-I). The new antihypertensive factor was purified almost completely by gel filtration on a Sephadex LH-20 column, and found to contain no phosphorus. It was tentatively named Peritoneal Dialysate Depressor-II. The main spot detected on preparative thin-layer chromatography by charring with ethanolic sulfuric acid reagent was found to be responsible for the antihypertensive action. This factor caused a sharp decrease in systemic arterial blood pressure of rats, cats and guinea pigs when injected into the femoral vein. There was no significant change in the heart rate during this hypotension. The hypotensive activity was not affected by previous treatment of the rats or guinea pigs with antimuscarinic, antihistaminic, beta-adrenergic-blocking or ganglionic-blocking agents. The antihypertensive effect of the factor was unaffected on rats pretreated with yohimbine, indomethacin or theophylline. In spinal or reserpinized rats, no detectable reduction of the depressor activity was observed. The factor did not affect isolated guinea pig ileum. Its depressor activity was not changed significantly by its treatment with proteases. No prostaglandin E or F series compounds were detected in the preparation by fluorometric assay with 15-hydroxyprostanoate oxido-reductase and resazurin. The hypotensive factor caused no aggregation of cat or rabbit platelets.(ABSTRACT TRUNCATED AT 250 WORDS)
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Tsukatani H, Yoshida J, Takauchi K, Yamada S, Tokumura A, Nakanishi K, Hayakawa T. Comparison of antispasmodic effect of synthetic lysolecithins with various fatty acid moieties on guinea pig ileum. JOURNAL OF PHARMACOBIO-DYNAMICS 1984; 7:400-6. [PMID: 6481614 DOI: 10.1248/bpb1978.7.400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Non-competitive antispasmodic effects of 8 kinds of synthetic L-alpha-lysolecithins (1-O-acyl-2-lyso-sn-glycero-3-phosphocholine, LPC) with various fatty acid moieties were examined upon the spasmodic actions of histamine and acetylcholine on guinea pig ileum. Five-min pretreatment of the gut with the synthetic LPC was required to be effective. With increase of the concentration of a synthetic LPC for pretreatment of the ileum, the slope of the dose-response curve of histamine or acetylcholine added cumulatively became more gentle, the maximal contraction was suppressed apparently, and which were associated with the shift of the curve to the higher concentration of the stimulants. Of LPCs with saturated fatty acid palmitoyl-LPC showed the strongest effect, followed by myristoyl-, stearoyl-, lauroyl- and decanoyl-LPCs in order. Incorporation of cis-double bond into the C18 fatty acid chain of LPC resulted in slight decrease of the antispasmodic effect. The relaxating effect of LPCs on perfused rabbit ear vessel preparations was similar in order.
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Tokumura A, Harada K, Yoshioka Y, Tsukatani H, Handa Y. Analyses of lysophosphatidic acids by gas chromatography mass spectrometry without hydrolytic pretreatment. BIOMEDICAL MASS SPECTROMETRY 1984; 11:167-171. [PMID: 6563919 DOI: 10.1002/bms.1200110406] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Lysophosphatidic acids having different fatty acyl moieties were directly analysed by gas chromatography/mass spectrometry after silylation. Trimethylsilyl derivatives of various LPAs escaped thermal degradation, and electron impact and chemical ionization of these derivatives yielded many ions which were useful for the structural determination. It was found by this new method that five species of lysophosphatidic acids were formed in rat plasma during incubation at 37 degrees C.
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Tokumura A, Fukuzawa K, Tsukatani H. Contractile effect of 1-O-hexadecyl-2-O-acetyl-sn-glycero-3-phosphocholine on strips of isolated rat intestine. J Pharm Pharmacol 1984; 36:210-2. [PMID: 6144763 DOI: 10.1111/j.2042-7158.1984.tb06945.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The contractile effects of AGEPC were examined on various regions of rat isolated intestine. The duodenum, jejunum and ileum showed only the tonic component of contraction to AGEPC at the low dose (less than 10(-9) M) but at the high dose (10(-7) M) biphasic contractions were induced, consisting of a phasic followed by a tonic component. In the colon, however, the AGEPC-induced maximum contraction was comparable in magnitude to that produced by acetylcholine; also the contraction profile was different from that elicited from the other regions of the intestine. Low doses of AGEPC caused a slow, sustained contraction and at high doses phasic and tonic components were not dissociated.
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Tokumura A, Harada K, Fukuzawa K, Tsukatani H. Biphasic action of platelet-activating factor on isolated guinea-pig ileum. Lipids 1983; 18:848-50. [PMID: 6656539 DOI: 10.1007/bf02534647] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
1-0-Hexadecyl-2-0-acetyl-sn-glycero-3-phosphocholine (platelet-activating factor) at 10(-10)-10(-9) M induced slow contraction of isolated guinea-pig ileal muscles and the contraction persisted for a long time. At a higher concentration of 10(-7) M, this phospholipid induced more rapid, but not greater, contraction. At higher concentrations (10(-6)-10(-5) M), this phospholipid induced a biphasic response: rapid contraction followed by relaxation. At high concentrations, this compound inhibited acetyl-choline-induced contractions. The stimulatory effect of this phospholipid was ca. 300 times that of 1-palmitoyl-2-0-acetyl-sn-glycero-3-phosphocholine, while its inhibitory potency on induced contraction was similar to those of 1-palmitoyl-2-0-acetyl-sn-glycero-3-phosphocholine and its lyso derivative. It was suggested that the differences in effects on contraction of different concentrations of 1-0-hexadecyl- and 1-palmitoyl-2-0-acetyl-sn-glycero-3-phosphocholine were due to the effects of these compounds on the ileum: a strong stimulatory effect and a moderate inhibitory effect on contraction.
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Tokumura A, Fukuzawa K, Tsukatani H. Contractile actions of lysophosphatidic acids with a chemically-defined fatty acyl group on longitudinal muscle from guinea-pig ileum. J Pharm Pharmacol 1982; 34:514-6. [PMID: 6126563 DOI: 10.1111/j.2042-7158.1982.tb04776.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Various lysophosphatidic acids caused phasic contractions of longitudinal muscle from guinea-pig ileum, followed by rhythmical contractions of lower magnitude. Polyunsaturated lysophosphatidic acids were more potent than saturated lysophosphatidic acids. Among the lysophosphatidic acids tested, linolenoyl-lysophosphatidic acid was the most active, but its activity was about 3-5 times less than that of prostaglandin F2 alpha. Contractile responses to various lysophosphatidic acids, were partially suppressed by tetrodotoxin, atropine and chlorpheniramine. In addition, lysophosphatidic acid-induced contractions were considerably reduced by pretreatment of the muscle with indomethacin.
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Fukuzawa K, Tokumura A, Ouchi S, Tsukatani H. Antioxidant activities of tocopherols on Fe2+-ascorbate-induced lipid peroxidation in lecithin liposomes. Lipids 1982; 17:511-3. [PMID: 7121213 DOI: 10.1007/bf02535334] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The antioxidant activities of 4 tocopherols, tocol, and a water-soluble model analog of alpha-tocopherol were compared. Egg lecithin liposomes were used and oxidation was catalyzed by Fe2+-ascorbate. The activities decreased in the order alpha greater than beta greater than gamma greater than delta-tocopherol greater than tocol, in agreement with their potencies in vivo. The water-soluble analog was the least effective. Activity depended on the molar ratio of antioxidant to unsaturated lipid, with one molecule each of the alpha-, beta-, gamma-, delta-tocopherol and tocol capable of protecting, respectively, 220, 120, 100, 30 and 20 molecules of polyunsaturated fatty acid. The mechanism of possible antioxidant effect of the compounds used is discussed.
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Tokumura A, Kume T, Fukuzawa K, Tsukatani H. Cardiovascular effects of lysophosphatidic acid and its structural analogs in rats. J Pharmacol Exp Ther 1981; 219:219-24. [PMID: 6116795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Injection of lysophosphatidic acid into anesthetized rats induced immediate hypertension, the effect depending on the structure of the sn-1-acyl moiety of the molecule. A hydroxyl group at the sn-2-position was not necessary, but a wedgeshaped structure was suitable for hypertensive activity. Most lysophospholipids with a chemical group attached to the phosphate portion had only weak hypotensive effects, but the sn-2-acetylated analogs of these depressor lysophospholipids elicited a hypotension at much lower doses. The durations of the hypotensions evoked by the sn-2-acetylated choline phospholipids were longer than those produced by 1-palmitoyl-2-acetoyl-sn-glycerol-3-phosphorylmethanol, ethanol and propanol.
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Tokumura A, Fukuzawa K, Isobe J, Tsukatani H. Lysophosphatidic acid-induced aggregation of human and feline platelets: structure-activity relationship. Biochem Biophys Res Commun 1981; 99:391-8. [PMID: 6909028 DOI: 10.1016/0006-291x(81)91758-7] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Handa Y, Matano K, Takauchi K, Tsukatani H. Sensitive gas chromatographic determination of certain glycerophosphates by use of the flame photometric detector. Application to glycerophospholipids. J Chromatogr A 1981; 206:387-91. [PMID: 7240356 DOI: 10.1016/s0021-9673(00)82553-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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50
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Fukuzawa K, Chida H, Tokumura A, Tsukatani H. Antioxidative effect of alpha-tocopherol incorporation into lecithin liposomes on ascorbic acid-Fe2+-induced lipid peroxidation. Arch Biochem Biophys 1981; 206:173-80. [PMID: 7212715 DOI: 10.1016/0003-9861(81)90078-3] [Citation(s) in RCA: 110] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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