Alpha adrenergic receptor blockade increases capillarization and fractional O2 extraction and lowers blood flow in contracting human skeletal muscle.
Acta Physiol (Oxf)
; 221(1): 32-43, 2017 Sep.
Article
em En
| MEDLINE
| ID: mdl-28199786
ABSTRACT
AIM:
To assess the effect of elevated basal shear stress on angiogenesis in humans and the role of enhanced skeletal muscle capillarization on blood flow and O2 extraction.METHODS:
Limb haemodynamics and O2 extraction were measured at rest and during one-leg knee-extensor exercise (12 and 24 W) in 10 healthy untrained young men before and after 4-week treatment with an α1 receptor-antagonist (Terazosin, 1-2 mg day-1 ). Corresponding biopsies were taken from the m. vastus lateralis.RESULTS:
Resting leg blood flow was increased by 57% 6 h following Terazosin treatment (P < 0.05), while basal capillary-to-fibre ratio was 1.69 ± 0.08 and increased to 1.90 ± 0.08 after treatment (P < 0.05). Leg O2 extraction during knee-extensor exercise was higher (4-5%; P < 0.05), leg blood flow and venous lactate levels lower (6-7%; P < 0.05), while leg VO2 was not different after Terazosin treatment.CONCLUSIONS:
These results demonstrate that daily treatment with an α-adrenergic receptor blocker induces capillary growth in human skeletal muscle, likely due to increased shear stress. The increase in capillarization resulted in an increased fractional O2 extraction, a lower blood flow and venous lactate levels in the exercising leg. The increase in capillarization, and concomitant functional readouts in the exercising leg, may provide a basis for novel angiotherapy.Palavras-chave
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Base de dados:
MEDLINE
Assunto principal:
Fluxo Sanguíneo Regional
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Músculo Esquelético
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Neovascularização Fisiológica
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Hemodinâmica
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article