IS HSP70 INVOLVED IN NITRIC OXIDE-INDUCED PROTECTION OF THE HEART

It is known that HSP70 plays an important role in the antiischaemic ef fect of adaptation to stress The aim of our study was to verify the hy pothesis that nitric oxide (NO) may contribute to the activation of HS P70 synthesis and to enhance thereby the resistance of organism to the ischaemic and reperfusion damages We observed that heat shock potenti ated NO production in the heart. NO formation was completely blocked b y the NO synthase inhibitor N-omega-nitro-L-arginine (L-NNA). L-NNA al so significantly attenuated the heat shock-induced accumulation of HSP 70 (by 45 % in heart). Both heat shock and NO donor induced time- and concentration-dependent HSP70 synthesis in the culture of human hepato blastoma cells Hep G2. Prior injection of NO donor (30-100 mg per rat) exerted a dose-dependent protective effect on the isolated heart in i schaemia and reperfusion within 24 hours We suggest that NO is involve d in the activation of HSP70 synthesis which can play an important rol e in the Belayed protective effect of NO donors.