Objective　To investigate the changes of ataxia-telangiectasia mutated (ATM)-Akt in the myocardium around the infarcted zones and its intervention by phenylephrine in rats. 　Methods　Myocardial infarction (MI) and sham operation were established in Sprague Dawley male rats by Litwin’s method. Three days after operation

surviving rats were divided into MI group (n=8)

sham operation group (n=8)

MI phenylephrine intervention group [n=8

phenylephrine 0.65 mg/(kg·d)

i.p.

for 8 weeks)

and sham operation phenylephrine intervention group (n=8

phenylephrine administered as above). Cardiac left ventricular posterior wall end-diastolic thickness (LVPWd)

left ventricular end-diastolic diameter (LVDd)

fractional shortening (FS) and ejection fraction (EF) were examined by Doppler ultrasonography. Twelve weeks after treatment

the expression of p-ATM substrate protein and p-Akt protein in the myocardium around the infarcted zones were detected by Western blot analysis and immunohistochemical assay respectively. 　Results　In 12 weeks after treatment

  LVDd （0.79±0.06） and （0.54±0.06） cm

FS (17.31±2.60)% and (38.58±2.56)%

and EF (67.75±3.54）% and (70.25±4.33)% (P0.05) respectively in group MI and sham operation. In group MI phenylephrine intervention and sham operation phenylephrine intervention groups

LVPWd was （0.12±0.01） and （0.13±0.03） (P0.05)

LVDd （0.64±0.05） and （0.66±0.06） cm

FS (32.00±2.73)% and (33.09±2.90)%

and EF (67.75±3.54）% and (70.25±4.33)% . The integration optical density of pATM substrate protein was (0.59±0.07) and (0.63±0.05) in MI and sham operation groups respectively (P0.05)

and was (0.99±0.07) and (0.65±0.04) in MI phenylephrine intervention group and sham operation phenylephrine intervention group respectively (P0.05). The numbers of pAkt positive cells were （74.38±3.06） and （74.50±3.99） in MI group and sham operation group respectively (P0.05); and were （98.80±3.17） and （75.88±2.77） in MI phenylephrine intervention group and sham operation phenylephrine interventin group respectively (P0.05). 　Conclusion 　There is no significant change in the expressions and activities of ATM-Akt signaling in myocardium around the infarcted zones. However

phenylephrine can significantly upregulate the expressions and activities of ATM-Akt signaling.