The direct effects of @entity452 on capillary blood volume (VOL) and blood flow velocity (VEL) are not known. We hypothesized that these would be more similar to that of @entity859 because of its effects on the beta(2) receptors on the coronary circulation. A total of 9 open-chest anesthetized @entity235 were studied after placement of 2 noncritical stenoses at rest and during separate intracoronary administrations of 5 microg/kg(-1)/min(-1) of @entity859 and 2 microg/kg(-1)/min(-1) of @entity452 . VOL and VEL were measured using myocardial contrast echocardiography, wall thickening with 2-dimensional echocardiography, and @entity296 ( @entity296 ) with radiolabeled microspheres. @entity452 increased the rate-pressure product significantly, whereas @entity859 had no effect on the rate-pressure product. In the normal myocardium, @entity859 had no effect on VOL and increases in @entity296 were all a result of increases in VEL. @entity452 also caused mostly an increase in VEL and only a 30% increase in VOL indicating modest capillary recruitment. In the bed with @entity850 both drugs attenuated increase in @entity296 by the same amount, which was associated with an attenuation in the increase in VEL secondary to a 15% increase in capillary resistance because of capillary derecruitment. The @entity296 -wall thickening relation was described for both drugs by the same function: y = 1 - exp(x) with wall thickening being significantly higher for @entity452 compared with @entity859 for each level of @entity296 . We conclude that the increase in @entity296 in the normal myocardium with intracoronary @entity452 occurs mostly from an increase in VEL rather than from an increase in VOL. In the bed with a noncritical @entity850 , the increases in @entity296 and VEL are similar for both drugs. Similar to intracoronary @entity859 , intracoronary @entity452 also caused capillary derecruitment distal to a noncritical @entity3979 .

Direct effects of @entity452 on the coronary microcirculation: comparison with XXXX using myocardial contrast echocardiography.

@entity296 :: ('MESH:D009202', 'Disease') :: ['MBF', 'myocardial blood flow'] @entity859 :: ('MESH:D000241', 'Chemical') :: ['adenosine'] @entity452 :: ('MESH:D004280', 'Chemical') :: ['Dobutamine', 'dobutamine'] @entity235 :: ('9615', 'Species') :: ['dogs'] @entity3979 :: ('MESH:D023921', 'Disease') :: ['coronary stenosis'] @entity850 :: ('MESH:D003251', 'Disease') :: ['stenosis']
@entity859 :: (MESH:D000241,Chemical) :: ['adenosine']
