Cardiovascular Pharmacology

Chiral selective effects of doxazosin enantiomers on blood pressure and urinary bladder pressure in anesthetized rats

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Abstract

Aim:

To study chiral selective effects of doxazosin enantiomers on blood pressure and urinary bladder pressure in anesthetized rats.

Methods:

In anesthetized rats, the carotid blood pressure, left ventricular pressure of the heart and the urinary bladder pressure were recorded.

Results:

Administration of S-doxazosin at 0.25, 2.5, 25, and 250 nmol/kg iv produced a dose-dependent decrease in blood pressure, but its depressor effect was significantly weaker than that induced by R-doxazosin and racemic-doxazosin (rac-doxazosin), and the ED30 values (producing a 30% decrease in mean arterial pressure) of R-doxazosin, rac-doxazosin and S-doxazosinwere 15.64, 45.93, and 128.81, respectively. Rac-doxazosin and its enantiomers administered cumulatively in anesthetized rats induced a dose-dependent decrease in the left ventricular systolic pressure and ±dp/dtmax, and the potency order of the 3 agents was R-doxazosin >rac-doxazosin >S-doxazosin. Rac-doxazosin and its enantiomers decreased the vesical micturition pressure dose-dependently at 2.5, 25, and 250 nmol/kg, and the inhibitory potency among the 3 agents was not significantly different.

Conclusion:

S-doxazosin decreases the carotid blood pressure and left ventricular pressure of the heart less than R-doxazosin and rac-doxazosin, but its effect on the vesical micturition pressure is similar to R-doxazosin and rac-doxazosin, indicating that S-doxazosin has chiral selectivity between cardiovascular system and urinary system in anesthetized rats.

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Author information

Correspondence to Lei-ming Ren.

Additional information

Project supported by the Hebei Natural Science Foundation (No C2006000802).

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Keywords

  • R-doxazosin
  • S-doxazosin
  • blood pressure
  • ventricular pressure
  • urinary bladder pressure
  • rat

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