Effect of multiple arterial haemorrhage on the coronary circulation

In the open-chest anesthetized dog, multiple arterial haemorrhage induces a reduction of the mean coronary flow, an absote or relative increase of the phasic flow during the early ventricular ejection phase and a decrease during the remaining phases of the cardiac cycle. When blood pressure falls sharply during the haemorrhage, coronary vascular resistance increases, whereas it does not change or decreases when blood pressure falls slowly. Moreover, coronary vascular resistance decreases transiently after the stoppage of the haemorrhage.     

Effect of isometric exercise on catecholamines in the coronary circulation.

Arterial and coronary sinus blood levels of catecholamines, adenosine 3', 5'-cyclic monophosphate (c-AMP) and lactate were measured during isometric exercise in fourteen patients. In no patient did lactate production occur. Mean resting total catecholamine levels both arterial (0.53 +/- 0.07 ng/ml; 2.94 +/- 0.38 nmol/l) and coronary sinus (0.4 +/- 0.08 ng/ml; 2.22 +/- 0.44 nmol/l), did not change significantly on exercise. Coronary sinus c-AMP levels fell on exercise from 11.5 +/- 0.8 nmol/l (resting) to 9.9 +/- 0.8 nmol/l (exercise) (P less than 0.01) with an arterial-coronary sinus difference of 1.2 nmol/l (P less than 0.01) on exercise. Our findings suggest that isometric exercise does not normally result in excessive cardiac symphathetic activity.     

Effect of papaverine on pulmonary vascular permeability to proteins

Previous studies have suggested that papaverine, a drug commonly used in studies of transvascular fluid and solute exchange to eliminate confounding effects of changes in vascular tone, may itself increase vascular permeability. In this study, we determined the ability of papaverine to alter pulmonary vascular protein permeability by measuring the osmotic reflection coefficient (sigma) for total proteins in a canine isolated perfused left lower lung lobe (LLL) preparation. The reflection coefficient, determined by the hematocrit-protein double-indicator technique, for control LLL's was 0.83 +/- 0.04 (SE) (n = 7). In separate groups of LLL's, blood papaverine HCl concentrations of 10(-5), 10(-4), and 10(-3) M resulted in sigma's of 0.84 +/- 0.02 (n = 6), 0.73 +/- 0.04 (n = 7), and 0.53 +/- 0.04 (n = 6), respectively. When two LLL's from the 10(-4) M group with sigma's of 0.56 and 0.57 were excluded from the analysis, the average sigma for this group was 0.79 +/- 0.02. We conclude that papaverine increases protein permeability at a concentration of 10(-3) M but does so in only some lobes at 10(-4) M. These results suggest that caution be taken when using high concentrations of papaverine in fluid balance studies.