Involvement of Catecholamines in the Myocardium of Rats Submitted to Experimental Model of Portal Hypertension

Abstract

Background: The role of autonomic nervous system in the development and maintenance of portal hypertension is not fully elucidated. It is known that the gene expression of norepinephrine in the superior mesenteric artery varies with time, and it may contribute for splanchnic vasodilation and its consequent hemodynamic repercussions. It is still not known exactly how the adrenergic expression behaves at the heart level in the initial stages of this process. Aim: To evaluate the immunohistochemical expression of the enzyme tyrosine hydroxylase (tyrosine 3-monooxygenase), involved in the synthesis of norepinephrine, in the myocardium of rats submitted to partial ligation of the portal vein. Methods: Twenty-four Wistar rats were divided into two groups: Sham Operated and Portal Hypertension. The partial ligation was performed in the Portal Hypertension group, and after 1/6/24 h and 3/5/14 days the animals were euthanized. Immunohistochemical analysis was performed to quantify the expression of the stained enzyme using the ImageJ program. Results:The Portal Hypertension group expressed percentages between 4.6-6% of the marked area, while the Sham Operated group varied between 4-5%. Although there was no statistical significance, the percentage stained in the Portal Hypertension group followed an increasing pattern in the first 6 h and a decreasing pattern after 24 h, which was not observed in the Sham Operated group. Conclusion: The expression of noradrenaline in rat myocardium during the first two weeks after partial ligation of the portal vein, with tyrosine hydroxylase as marker, did not show differences between groups over time.

Clinical diagnosis of pheochromocytoma and paraganglioma‐induced secondary hypertension through UPLC‐MS/MS analysis of plasma catecholamines and their metabolites

“…Catecholamines exert multiple metabolic and cardiovascular effects, such as elevation of blood pressure, myocardial contractility, heart rate, and cardiac conduction velocity via three major receptors, namely, α, β, and dopaminergic receptors 6 . Catecholamines are involved in diverse metabolic processes and regulatory systems, and are hence vital biomarkers for the diagnosis and treatment of PPGL and primary hypertension 7,8 . The surge of catecholamines from PPGLs can be persistent or intermittent, which results in different clinical presentations; specifically as some catecholamines induce sustained hypertension, while others induce paroxysmal hypertension 9 .…”

“… 6 Catecholamines are involved in diverse metabolic processes and regulatory systems, and are hence vital biomarkers for the diagnosis and treatment of PPGL and primary hypertension. 7 , 8 The surge of catecholamines from PPGLs can be persistent or intermittent, which results in different clinical presentations; specifically as some catecholamines induce sustained hypertension, while others induce paroxysmal hypertension. 9 Catecholamines, including dopamine and norepinephrine, and their metabolites, including metanephrine, vanillylmandelic acid (VMA), and normetanephrine, have been investigated as biomarkers for the diagnosis of PPGL and hypertension.…”

Carvedilol as Primary Prophylaxis for Gastric Variceal Bleeding in Portal Hypertension Model in Rats

“…On the other hand, cirrhotic PH is associated with an increase in hepatic vascular resistance to blood flow 5 , 9 . PH is the major cause of morbidity and mortality in patients with cirrhosis due to the development of complications, mainly esophagogastric varices 16 , ascites, renal dysfunction, and hepatic encephalopathy 7 . The development of these complications occurs when portal pressure, directly measured, is greater than 10 mmHg and for bleeding when the gradient is greater than 12 mmHg 5 .…”