Oxygen-Derived Free Radical Stress Activates Nonselective Cation Current in Guinea Pig Ventricular Myocytes
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Abstract Oxygen-derived free radicals (O-Rs) cause alterations in cardiac electrical activity, including sustained depolarization, which may contribute to arrhythmic activity in reperfusion after ischemia. The ionic current(s) and cellular mechanism(s) underlying the sustained depolarization are not well defined. We used the whole-cell variant of the patch-clamp technique to study sustained depolarization in guinea pig ventricular myocytes during the extracellular application of O-Rs (generating system: dihydroxyfumaric acid, 3 to 6 mmol/L; FeCl 3 /ADP, 0.05:0.5 mmol/L). Myocytes superfused with O-Rs (pipette EGTA, 0.1 mmol/L) showed (1) sustained depolarization to between −40 and −10 mV, (2) oscillations in membrane potential, and (3) triggered activity. The depolarization resulted from an increase in quasi–steady state difference current reversing at ≈−18 mV, and the oscillations were due to transient inward current. The latter were inhibited with ryanodine (10 μmol/L) or high pipette EGTA (5 mmol/L), but the steady state current was unaffected. Nonselective cation current (I NSC ) (recorded with Cs + , Li + , and Mg 2+ replacing K + , Na + , and Ca 2+ , respectively; 20 mmol/L tetraethylammonium chloride [TEA] and 5 mmol/L BAPTA in the pipette solution and 10 mmol/L TEA, 10 μmol/L tetrodotoxin, and 10 μmol/L nicardipine in the bath solution) was activated by O-Rs; the increase in current was unaffected by preventing changes in [Ca 2+ ] i but was inhibited with dithiothreitol. Oxidizing agents (diamide and thimerosal) or caffeine (pipette EGTA, 0.1 mmol/L) produced a similar increase in membrane conductance. I NSC activated with O-Rs, oxidizing agents, or caffeine was sensitive to SK&F 96365. O-R treatment was without effect when I NSC was already activated with caffeine. The data suggest that (1) extracellular O-Rs activate a Ca 2+ -sensitive I NSC in the absence of changes in [Ca 2+ ] i , (2) oxidative modification of extracellular sulfhydryl groups may be involved, and (3) this mechanism is different from the Ca 2+ -dependent activation of I NSC by intracellular O-Rs, indicating that O-Rs may alter ion channel activity by differential mechanisms, depending on the compartment, extracellular or intracellular, in which they are present.(1) Guinea pig (Hartley strain) 内リンパ液中には, 補体が存在し, その補体価は3.70u/mlであった.(2) Guinea pig (Hartley strain) と C4D Guinea pig をウサギの血管条+Complete Adjuvant (Freund s') を抗原として, 感作すると Guinea pig (Hartley strain) 10匹中4匹に内リンパ水腫の発現があった. C4D Guinea pig 18 匹には内リンパ水腫が認められなかった.上記の結果より内リンパ液中に補体が存在し, 局所でのICの形成の可能性や感染防禦に重要な役割を演じ, また内リンパ水腫の発現には主に classical pathway が関与していると考える.
Endolymphatic hydrops
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Guinea pigs may be sensitized for PC A reactions by guinea pig 7S gamma 1 antibodies but not by guinea pig 7S gamma 2 antibodies. However, with all other species capable of sensitizing the guinea pig, it is always the 7S gamma 2 antibody type which mediates sensitization of guinea pigs for PCA.
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Growth hormone releasing activity of a guinea-pig hypothalamic extract has been evaluated in guinea pig and rat. Guinea-pig stalk median eminence (SME) extracts injected in the carotid arteries of both guinea pig and rats induce a marked depletion of pituitary growth hormone content. The potential importance of a relative lack of species-specificity for growth hormone releasing factor (s) is considered.
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To investigate the immunology base of Zmu-1:DHP guinea pig sensitive to virus infection,the Ig and T lymphocytic proliferation rate were determined by ELISA and FCM means.The suitable immune dosage of OVA is 0.1 mg per guinea pig.After immunization with OVA,the level of characteristic IgG,IgG1,IgG2 in Zmu-1:DHP guinea pig serum is approximately the same as DHP guinea pig,but its T lymphocytic proliferation rate is prominently lower than that of DHP guinea pig.The content of IgE in both of guinea pig sera is very low.The variation of IgG1 content is larger between immunization groups with or without Al(OH)_3.The cytoimmune function of Zmu-1:DHP guinea pig is lower than that of DHP guinea pig and the body fluid immune function is as the same as DHP guinea pig.The lower T lymphocytic function is probably one of the causes of arousing more sensitive to some virus in Zmu-1:DHP guinea pig.Thus Zmu-1:DHP guinea pig may fit to be used as an infectious animal model,and to investigate the immunogenic mechanism.
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Page . Column . Line . For . Read . 1480 1 ↑ Guinea pig hen Fig. 7 mg/g lane F 5.8, lane G 0.3 lane F 2.3, lane G 0.8 legend 4 guinea pig (F), hen (G) hen (F), guinea pig (G) 1481 Fig. 8 mg/g lane F 0.8, lane G 0.6 lane F 0.4, lane G 2.5 legend 4 guinea pig (F) hen(F) legend 5 hen (G) guinea pig (G) 2 15 guinea pig hen 20 hen guinea pig 23 guinea pig hen 26 guinea pig hen 29 guinea pig hen 1482 Fig. 9 upper figure Guinea Pig hen legend 1 guinea pig hen 1483 1 ↑ 13 guinea pig hen 1484 1 12 1 guinea pig hen 13–14 guinea pig hen Page . Column . Line . For . Read . 1480 1 ↑ Guinea pig hen Fig. 7 mg/g lane F 5.8, lane G 0.3 lane F 2.3, lane G 0.8 legend 4 guinea pig (F), hen (G) hen (F), guinea pig (G) 1481 Fig. 8 mg/g lane F 0.8, lane G 0.6 lane F 0.4, lane G 2.5 legend 4 guinea pig (F) hen(F) legend 5 hen (G) guinea pig (G) 2 15 guinea pig hen 20 hen guinea pig 23 guinea pig hen 26 guinea pig hen 29 guinea pig hen 1482 Fig. 9 upper figure Guinea Pig hen legend 1 guinea pig hen 1483 1 ↑ 13 guinea pig hen 1484 1 12 1 guinea pig hen 13–14 guinea pig hen Open in new tab
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An incompatibility in the reaction of human C2 with EAC14 consisting of guinea-pig C4 was demonstrated. Human C2 reacted poorly with EAC14 consisting of guinea-pig C4. The substitution of guinea-pig C4 on EAC14 with human C4 resulted in the fifteen- to twenty-fold increase of the haemolytic activity of C2 in whole human serum. It became more manifest in the titration of purified human C2. Purified human C2 showed about 100 times more activity with EAC14 consisting of human C4, although guinea-pig C2 reacted effectively with EAC14 carrying either guinea-pig or human C4. The unsuitability of the measurement of human C2 employing EAC14 prepared with guinea-pig C4 was shown.
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The isoelectric point (pI) of human and guinea-pig C2 was determined by electrofocusing. The results showed that human C2 and C2 of some guinea-pigs had a pI of approximately pH 5.5–5.6; in some guinea-pig sera C2 activity was resolved into two fractions, one with a pI of about 5.2 and the other of about 5.5. The data suggest the possibility that guinea-pig C2 may exist in at least two allotypic forms.
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Intraperitoneal injection
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Complement
New guinea
Component (thermodynamics)
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Free secretory component (FSC) was purified from guinea-pig milk by gel-filtration and immunoabsorption on anti-SC antibodies. Guinea-pig FSC cross-reacted with antisera to human FSC, and the reverse. Guinea-pig and human FSC resembled each other in molecular size, electrophoretic mobility and heterogeneity, as well as by the existence of antigenic determinants restricted to the unassociated form of the molecule. Guinea-pig FSC associates in vitro with guinea-pig IgM. Distribution of disulphide links is required to set free guinea-pig FSC from secretory IgA.
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