Related Experiment Video
Updated: Aug 14, 2026

Isolation of Intrapulmonary Artery and Smooth Muscle Cells to Investigate Vascular Responses
Published on: June 8, 2022
Regulation of myosin light chain phosphatase and pulmonary arterial relaxation
1Department of Pediatrics, University of Manitoba, Winnipeg, Canada. dakshina@cc.umanitoba.ca
Abstract:
Neonatal circulatory transition is dependent upon tightly regulated pulmonary circuit relaxation. Persistent pulmonary hypertension (PPHN), a rapidly progressive disease of pulmonary arterial vasospasm and remodelling, may be characterized by pulmonary arterial myocyte relaxation failure. A key regulator of vascular tone is myocyte calcium sensitivity, determined by the relative stoichiometry of myosin light chain phosphorylation and dephosphorylation. We have recently reported downregulation of myosin light chain phosphatase activity in a hypoxic model of neonatal pulmonary hypertension. This review examines the recognized pathways of regulation governing myosin light chain phosphatase activity, including targeting subunit isoform switching, targeting unit phosphorylation and catalytic site inhibition. In light of the reviewed literature, further speculation is proposed on the potential contributions of these mechanisms to the pathophysiology of the perinatal pulmonary arterial relaxation defect in PPHN.
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