Abstract: AIM: To observe the dysfunciton of my-ocardial nuclear calcium transport in rat myocardial injury and the effects of liqustraxin on it.METHODS: The model of myocardial damage was induced by subcutaneous injection of isoproterenol (ISO, 5 mg·kg^-1 ·d^-1 ).My-ocardial nuclei were purified with sucrose density centrifu-gation and identified zymologically.The activity of Ca²⁺-ATPase was measured zymologically and calcium uptake was assayed with ⁴⁵Ca²⁺ isotope.RESULTS: Compared with the control, the Ca²⁺-ATPase activity of myocardial nuclear membrane in ischemia group(exprimental) was decreased by 18.1%(P<0.05), the nuclear ⁴⁵Ca²⁺ up-take was significantly decreased and V_max value was low-ered by 54.6%.V_max and K_m of ATPase activity de-creased by about 33.0%(P<0.05) and 42.8%(P< 0.01) respectively.Compared with the control, Ca²⁺-ATPase activity and 45 Ca²⁺ uptake in the myocardial nu-clei of the liqustraxin group showed no significant change.CONCLUSION: Liqustraxin has notable protective ef-fects on dysfunction of nuclear calcium transport in rat myocardium.

Key words: liqustraxin, Ca²⁺ transport, Ca²⁺-AT-Pase, nucleus/myocardium