The effect of dopexamine HCl upon collateral perfusion of the acutely ischemic myocardium in anesthetized dogs. The effects of low-dose (10(-9) and 3 x 10(-9) mole/kg/min) infusions of dopexamine HCl, a new synthetic catecholamine with beta 2-adrenergic and DA1-dopaminergic agonostic actions, was tested in anesthetized dogs, with and without acute ligation of the left anterior descending coronary artery. The infusions caused diastolic arterial blood pressure to fall by 12 +/- 4 and 23 +/- 5 mmHg, respectively. Microsphere-estimated collateral blood flow to the ischemic myocardium did not change significantly during the drug infusions. The findings suggest that low doses of dopexamine HCl do not cause coronary "steal" from acutely ischemic myocardium. 