What inhibits hypoxic pulmonary vasoconstriction?

Molecular mechanism. The classical explanation of HPV involves inhibition of hypoxia-sensitive voltage-gated potassium channels in pulmonary artery smooth muscle cells leading to depolarization.

How does hypoxia cause pulmonary vasoconstriction?

In systemic arteries hypoxia causes an increased current through ATP-dependent potassium channels and vasodilatation, whereas in the pulmonary arteries hypoxia inhibits potassium current and causes vasoconstriction.

What triggers pulmonary vasoconstriction?

Pulmonary vasoconstriction can be caused by serotonin, endothelin-1 (ET-1), angiotensin II, histamine, and prostaglandins. Several of these factors derive from the vascular endothelium.

How does hypoxia affect pulmonary blood flow?

During hyperoxia, total resistance decreased with increased blood flow because of a reduction of microvascular resistance. In contrast, during hypoxia, not only microvascular resistance but also arterial resistance decreased with increase of blood flow while venous resistance remained unchanged.

What drugs cause lung disease?

Many medicines and substances are known to cause lung disease in some people. These include: Antibiotics, such as nitrofurantoin and sulfa drugs. Heart medicines, such as amiodarone . Chemotherapy drugs such as bleomycin, cyclophosphamide, and methotrexate . Street drugs.

What causes pulmonary artery constriction?

In most patients with COPD , decreased oxygen in the alveoli is due to the lung disease. The hypoxia is the cause of constriction of the small pulmonary artery blood vessels, the pulmonary arterioles.

What is decreased pulmonary blood flow?

The decrease in pulmonary blood flow occurs as blood shunts right to left at either the atria level or ventricular level through a hole in the septum because the blood is unable to leave the heart due to an obstruction or defect in a valve, vessel, or chamber on the right side of the heart.