The dynamics of neuropeptide Y protein expression in the developing mouse heart

Abstract

The current study investigates the spatio‐temporal pattern of neuropeptide Y protein expression in coronary vessels and cardiac nerves during development of the mouse heart. The hearts of the C57BL/6 mice were collected on embryonic days 16 to 19 and on postnatal days 3 to 21. They were immersion‐fixed with 4% PFA/PBS and processed for cryo‐sectioning. The serial histological cross‐sections through the heart ventricles were immunostained with an antibody against NPY alone or in combination with Griffonia simplicifolia IB4 lectin, the antibodies against α‐smooth muscle (SM) actin and 150 kDa neurofilaments. We found that during embryonic and postnatal development, the coronary vessels demonstrated a high level of variability in the intensity of NPY immunostaining. Furthermore, whereas during embryogenesis, NPY was primarily expressed in the endothelial cells (ECs) of the coronary vessels, in postnatal period, the NPY immunostaining was typically detected in vascular SM cells. More importantly, the disappearance of NPY expression in ECs closely correlated with a significant expansion of NPY‐containing perivascular nerves. Therefore, our findings suggest that NPY has distinct dynamics of expression within the cells of developing coronary vessels and perivascular nerves, indicating its potential involvement in regulation of coronary vessel formation and/or function during development of the mouse heart.Grant Funding Source: Internal Award from the NYCOM Office of Research