Abstract
In the present study we aimed to assess the effect of α1-adrenoceptor blockade on resting and hyperemic myocardial blood flow in normal humans. Myocardial blood flow, at baseline and after dipyridamole, was measured with positron emission tomography and 15O-labeled water in 11 normal volunteers at control and during α1-blockade with doxazosin. Baseline myocardial blood flow during α1-blockade was not different from control, whereas coronary resistance was significantly lower (73.48 ± 18.31 vs. 89.84 ± 27.96 mmHg · min · ml-1 · g-1; P <0.05). After dipyridamole, myocardial blood flow during α1-blockade was significantly higher (3.50 ± 0.75 vs. 2.58 ± 0.54 ml · min-1 · g-1; P <0.01) and coronary resistance lower (25.30 ± 7.37 vs. 33.89 ± 7.04 mmHg · min · ml-1 · g-1; P <0.01) compared with control. In conclusion, in normal humans, dipyridamole-induced increase in myocardial blood flow is limited by α1-mediated coronary vasoconstriction.
| Original language | English |
|---|---|
| Journal | American Journal of Physiology - Heart and Circulatory Physiology |
| Volume | 271 |
| Issue number | 4 40-4 |
| Publication status | Published - Oct 1996 |
Keywords
- autonomic nervous system
- coronary resistance
- positron emission tomography
ASJC Scopus subject areas
- Physiology
- Physiology (medical)