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A Pilot Study to Assess Adenosine 5 ’ -triphosphate Metabolism in Red Blood Cells as a Drug Target for Potential Cardiovascular Protection

View Article: PubMed Central

ABSTRACT

Objective: To study the effect of exercise preconditioning on adenosine 5’triphosphate (ATP) metabolism in red blood cells and cardiovascular protection against injury induced by isoproterenol in vivo.

Methods: Male Sprague Dawley rats (SDR) were each exercised on a treadmill for 15 minutes at 10 m/min and 10% grade (n = 7) (LowEx), or 14 m/min and 22% grade (n = 8) (VigEx). Two hours after the exercise, each rat received a single dose of isoproterenol (30 mg/kg) by subcutaneous (sc) injection. Two separate groups of SDR were used as control: One received no exercise (n = 10) (NoEx) and the other received no exercise and no isoproterenol (n = 11) (NoIso). Serial blood samples were collected over 5 hours for measurement of ATP and its catabolites by a validated HPLC. Hemodynamic recording was collected continuously for 
the duration of the experiment. Data were analysed using ANOVA and t-tests and difference considered significant at 
p < 0.05.

Results: Exercise pre-conditioning (both LowEx and VigEx) reduced mortality after isoproterenol from 50% to < 30% 
(p > 0.05). It attenuated the rebound in blood pressure significantly (p < 0.05 between NoEx vs VigEx), attenuated the increase of RBC adenosine 5’-monophosphate (AMP) concentrations induced by isoproterenol, and also decreased the breakdown of ATP to AMP in the RBC (p < 0.05 vs NoEx).

Conclusion: Exercise pre-conditioning decreased the blood pressure rebound and also breakdown of ATP in RBC after isoproterenol which may be exploited further as a drug target for cardiovascular protection and prevention.

No MeSH data available.


Related in: MedlinePlus

Hemodynamic effects in response to isoproterenol injection (30 mg/kg) in rats with or without exercise preconditioning. Each point represents mean ± SEM. Systolic blood pressure SBP; diastolic blood pressure DBP; hear rate HR.
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Figure 4: Hemodynamic effects in response to isoproterenol injection (30 mg/kg) in rats with or without exercise preconditioning. Each point represents mean ± SEM. Systolic blood pressure SBP; diastolic blood pressure DBP; hear rate HR.

Mentions: There was no fatality in the rats which did not receive isoproterenol (NoIso). On the other hand, 5 of the 10 rats died from the injury (50% mortality) within 4 hrs after the isoproterenol (30 mg/kg) injection without exercise pre-conditioning (NoEx) (p < 0.05). The mortality was reduced to < 30% in the exercise groups (2 of 7 and 2 of 8 died in LowEx and VigEx, respectively). However due to the small number of rats in each group, the reduction in mortality from the exercise pre-conditioning was not statistically significant (p > 0.05). Immediately after isoproterenol injection (30mg/kg), SBP and DBP fell sharply in both exercise groups (LowEx and VigEx) and the NoEx group, in contrary, the heart rate (HR) increased in the study groups receiving isoproterenol (p < 0.05 vs before isoproterenol, paired t-test) (Table 2). Both SBP and DBP rebounded shortly after (1 – 2 hr after isoproterenol) to near pre-isoproterenol levels in the three groups (Fig. 4). However, the % rebound was significantly less in the VigEx than the NoEx group (p < 0.05). The % rebound was also blunted in the LowEx group, although the decrease did not reach statistical significance (Table 2). HR remained elevated in all three isoproterenol groups until the end of the experiment (Fig. 4).


A Pilot Study to Assess Adenosine 5 ’ -triphosphate Metabolism in Red Blood Cells as a Drug Target for Potential Cardiovascular Protection
Hemodynamic effects in response to isoproterenol injection (30 mg/kg) in rats with or without exercise preconditioning. Each point represents mean ± SEM. Systolic blood pressure SBP; diastolic blood pressure DBP; hear rate HR.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4997928&req=5

Figure 4: Hemodynamic effects in response to isoproterenol injection (30 mg/kg) in rats with or without exercise preconditioning. Each point represents mean ± SEM. Systolic blood pressure SBP; diastolic blood pressure DBP; hear rate HR.
Mentions: There was no fatality in the rats which did not receive isoproterenol (NoIso). On the other hand, 5 of the 10 rats died from the injury (50% mortality) within 4 hrs after the isoproterenol (30 mg/kg) injection without exercise pre-conditioning (NoEx) (p < 0.05). The mortality was reduced to < 30% in the exercise groups (2 of 7 and 2 of 8 died in LowEx and VigEx, respectively). However due to the small number of rats in each group, the reduction in mortality from the exercise pre-conditioning was not statistically significant (p > 0.05). Immediately after isoproterenol injection (30mg/kg), SBP and DBP fell sharply in both exercise groups (LowEx and VigEx) and the NoEx group, in contrary, the heart rate (HR) increased in the study groups receiving isoproterenol (p < 0.05 vs before isoproterenol, paired t-test) (Table 2). Both SBP and DBP rebounded shortly after (1 – 2 hr after isoproterenol) to near pre-isoproterenol levels in the three groups (Fig. 4). However, the % rebound was significantly less in the VigEx than the NoEx group (p < 0.05). The % rebound was also blunted in the LowEx group, although the decrease did not reach statistical significance (Table 2). HR remained elevated in all three isoproterenol groups until the end of the experiment (Fig. 4).

View Article: PubMed Central

ABSTRACT

Objective: To study the effect of exercise preconditioning on adenosine 5&rsquo;triphosphate (ATP) metabolism in red blood cells and cardiovascular protection against injury induced by isoproterenol in vivo.

Methods: Male Sprague Dawley rats (SDR) were each exercised on a treadmill for 15 minutes at 10 m/min and 10% grade (n = 7) (LowEx), or 14 m/min and 22% grade (n = 8) (VigEx). Two hours after the exercise, each rat received a single dose of isoproterenol (30 mg/kg) by subcutaneous (sc) injection. Two separate groups of SDR were used as control: One received no exercise (n = 10) (NoEx) and the other received no exercise and no isoproterenol (n = 11) (NoIso). Serial blood samples were collected over 5 hours for measurement of ATP and its catabolites by a validated HPLC. Hemodynamic recording was collected continuously for &#8232;the duration of the experiment. Data were analysed using ANOVA and t-tests and difference considered significant at &#8232;p &lt; 0.05.

Results: Exercise pre-conditioning (both LowEx and VigEx) reduced mortality after isoproterenol from 50% to &lt; 30% &#8232;(p &gt; 0.05). It attenuated the rebound in blood pressure significantly (p &lt; 0.05 between NoEx vs VigEx), attenuated the increase of RBC adenosine 5&rsquo;-monophosphate (AMP) concentrations induced by isoproterenol, and also decreased the breakdown of ATP to AMP in the RBC (p &lt; 0.05 vs NoEx).

Conclusion: Exercise pre-conditioning decreased the blood pressure rebound and also breakdown of ATP in RBC after isoproterenol which may be exploited further as a drug target for cardiovascular protection and prevention.

No MeSH data available.


Related in: MedlinePlus