Effects of Tolazoline on Regional Blood Flows in the Newborn Piglet

Abstract

To assess the effects of intravenous tolazoline on hemodynamics and regional blood flow distribution, 12 anesthetized newborn piglets were studied. Six piglets received saline and served as controls, the other 6 received two bolus doses of tolazoline (1 and 2 mg/kg). Mean arterial blood pressure decreased from control levels of 69.4 ± 5.6 to 54.6 ± 7.0 and 47.0 ± 5.6 mm Hg, respectively, after 1 and 2 mg/kg of tolazoline, and heart rate increased from 220 ± 9 to 270 ± 13 and 282 ± 8 beats/min, respectively. Cardiac output and regional blood flows were measured 15 min after tolazoline by the radioactive microsphere technique. Cardiac index did not change significantly. There was a redistribution of cardiac output toward the coronary circulation, with an increase in coronary blood flow from a control value of 249.3 ± 39.9to 361.0 ± 56.4 ml/min/100 g of tissue after 1 mg/kg of tolazoline. Bronchial blood flow was also significantly increased. After a dose of 2 but not 1 mg/kg, the renal blood flow was markedly decreased from 139.8 ± 17.8 to 104.4 ± 24.5 ml/min/100g. The other regional blood flows were not significantly modified. We conclude that tolazoline is a potent coronary vasodilator during the neonatal period. In addition we speculate that the decrease in renal blood flow might play a role in the renal toxicity of tolazoline.

Tolazoline Decreases Survival Time During Microwave-Induced Lethal Heat Stress in Anesthetized Rats

“…For example, when administered to sheep, tolazoline (2 mg/kg) attenuated the bradycardia and tachypnea caused by xylazine (20). Tolazoline also caused tachycardia in a wide variety of species, at doses ranging from 1 to 6 mg/kg (21)(22)(23)(24)(25)(26). On the basis of our previous studies, possible associations of cardiovascular and respiratory changes with body temperature changes during MW exposure are of interest.…”

Glucagon-like peptide-2 acutely increases proximal small intestinal blood flow in TPN-fed neonatal piglets

“…In previous studies, radioactive and fluorescent microsphere deposition has been used to quantitate the effects of hormones and other agents on blood flow to GI tissues or organs (8,9,11,26,30). Therefore, the aim of the current study was to determine the effect of acute GLP-2 infusion on the distribution of blood flow in GI and other visceral organs in TPN-fed neonatal piglets using the fluorescent microsphere deposition method.…”