Heat shock potentiated the nitric oxide production (EPR assay) in the liver, kidney, heart, spleen, intestine, and brain. The heat shock-induced sharp transient increase in the rate of nitric oxide production preceded the accumulation of heat shock proteins (HSP70) (Western blot analysis) as measured in the heart and liver. In all organs the nitric oxide formation was completely blocked by the NO-synthase inhibitor /V%nitro-Larginine (L-NNA). L-NNA also markedly attenuated the heat shock-induced accumulation of HSP70. The results suggests that nitric oxide is involved in the heat shock-induced activation of HSP70 synthesis.
The diamagnetic binuclear form of dinitrosyl iron complexes (B-DNIC) with glutathione can be easily synthesized in the air at ambient temperature. The synthetic protocol includes consecutive addition to distilled water of glutathione, which decreases the pH of the test solution to 4.0, a bivalent iron salt (e.g., ferrous sulphate) and sodium nitrite at the molar ratio of 2:1:1, with a subsequent increase in pH to neutral values. Under these conditions, the amount of B-DNIC formed is limited by initial nitrite concentration. In the novel procedure, 20mM glutathione, 10mM ferrous sulfate and 10mM sodium nitrite give 2.5mM B-DNIC with glutathione, while 5mM glutathione remains in the solution. Bivalent iron (5mM) is precipitated in the form of hydroxide complexes, which can be removed from the solution by passage through a paper filter. After the increase in рН to 11 and addition of thiols at concentrations exceeding that of DNIC tenfold, B-DNIC are converted into a mononuclear EPR-active form of DNIC (M-DNIC) with glutathione. B-DNIC preparations synthesized by using new method contain negligible amount of nitrite or S-nitrosoglutathione as a contaminations. All the steps of DNIC synthesis were characterized by using optical, EPR and HPLC methods. A long-lasting hypotensive action of DNIC formed was demonstrated.
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