共查询到20条相似文献,搜索用时 31 毫秒
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- 1. 1.|α-MSH (1/2–13) was injected centrally and peripherally in rabbits exposed to cold.
- 2. 2.|Doses of the peptide previously shown to reduce fever had no effect on afebrile body temperature in the cold; larger doses did lower temperature.
- 3. 3.|We conclude that the antipyretic effect of small doses of α-MSH does not depend upon inhibition of central heat productioin and heat conservatioin pathways.
- 4. 4.|The antipyretic and hypthermic activities of α-MSH are independent and may represent different actions within the CNS.
Keywords: α-MSH; antipyretic/hypothermogenic; fever; central temperature controls; cold exposure; rabbits 相似文献
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Derrick K. Au Craig C. Malbon Fred R. Butcher 《Biochimica et Biophysica Acta (BBA)/General Subjects》1977,500(2):361-371
- • Beta-adrenergic receptor identification and properties are probed in rat parotid membranes utilizing the high affinity β-adrenergic antagonist(−)-[3H]dihydroalprenolol.
- • The binding of (−)-[3H]dihydroalprenolol to membrane preparations of parotid is rapid, equilibrium being reached in 5 min. Strict stereospecificity is observed, (−)-propanolol being 100 times more potent than (+)-propranolol in competing with (−)-[3H]dihydroalprenolol for binding sites. Beta-adrenergic agonists compete for the binding sites with (−)-[3H]dihydroalprenolol with the same characteristics, i.e., much higher concentrations of the (+)-stereoisomers than the (−)-stereoisomers are required to produce 50% inhibition, the range varies from 14-fold for epinephrine to 300-fold for isoproterenol. Among the (−)-stereoisomers, the relative potency of inhibitory action is (−)-propranolol > (−)-isoproterenol > (−)-epinephrine ≡ (−)-norepinephrine. (−)-Isoproterenol is about 20 times as potent as norepinephrine, the least potent agonist among all the catecholamine (−)-stereoisomers.
- • The binding of (−)-[3H]dihydroalprenolol is saturable, with a maximum number of binding sites equalling 450 fmol/mg protein and a dissociation constant of 7.9 nM. The Scatchard plots show no significant curvilinear character. Hill plots consistently give a Hill coefficient close to unity (0.92–1.05). Both pieces of evidence suggest a single-component system with no significant cooperativity.
- • Dissociation kinetics study after the method of De Metys et al. (1973) Biochem. Biophys. Res. Commun. 155, 154, indicates a lack of site-to-site interactions among the binding sites. The rate of dissociation of bound (−)-[3H]dihydroalprenolol is the same in the presence and absence of 1 · 10−5 M (±)-alprenolol.
- • Based on the binding of (−)-[3H]dihydroalprenolol, it is concluded that the beta-adrenergic receptors can be identified in rat parotid and that these binding sites display β1 character. Results of the study indicate a one-component system with no observable site-to-site interactions.
Abbreviations: DHA; dihydroalprenolol 相似文献
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Urashima T Nakamura T Teramoto K Arai I Saito T Komatsu T Tsubota T 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2004,139(4):687-595
Sialyl oligosaccharides were separated from two samples of Japanese black bear milk by extraction with chloroform/methanol, gel filtration on Bio Gel P-2, ion exchange chromatography on DEAE-Sephadex A-50 and high-performance liquid chromatography (HPLC) on a TSK gel Amido-80 column. They were characterized by 1H-NMR spectroscopy. The structures of four sialyl oligosaccharides separated from the milk were the following:
- Neu5Ac(α2-3)Gal(β1-4)Glc
- Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-3) Gal(α1-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-6) Gal(β1-4)Glc
- Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-3) Gal(α1-3)[Fuc(α1-2)]Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-6) Gal(β1-4)Glc
- Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-3)[Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc
Keywords: Japanese black bear milk; Milk oligosaccharides; Sialyl milk oligosaccharides; B antigen; α-Gal epitope; Ursidae; Ursus thibetanus japonicus; Japanese black bear 相似文献
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Howard Sands James Mascali Elisabeth Paietta 《Biochimica et Biophysica Acta (BBA)/General Subjects》1977,500(2):223-234
- 1. 1. Calcium transport into microsomal vesicles of respiratory (tracheal) smooth muscle was characterized. This calcium transport was ATP dependent and stimulated by the presence of the oxalate ion. The magnitude of transport was similar to that reported for microsomes from other types of smooth muscle.
- 2. 2. Bovine and rabbit, heavy and light microsomes were isolated from respiratory (tracheal) and vascualar (aortic) smooth muscle. Preincubation of these vesicles with cyclic AMP and protein kinase did not alter the transport of calcium into the vesicles. There was no evidence of phosphate incorporatio into microsomal membrane proteins. Similar results were obtained if phosphorylase b kinase replaced the combination of cyclic AMP and protein kinase during the preincubation.
- 3. 3. The phosphoprotein phosphatase activity of cardiac sarcoplasmic reticulum and smooth muscle microsomes was determined. The activity of this enzyme was found to be several-fold less in the cardiac sarcoplasmic reticulum than in various smooth muscle microsome preparations.
Abbreviations: EGTA; ethyleneglycol-bis(β-aminoethylether)N; N′-tetracetic acid 相似文献