Download neuropeptide y is a factor secreted by human endocardial

NEUROPEPTIDE Y IS A FACTOR SECRETED BY HUMAN ENDOCARDIAL
ENDOTHELIAL CELLS.
Danielle Jacques, Sawsan Sader, Ghassan Bkaily and Claudine Perreault.
Department of Anatomy and Cell Biology, Faculty of medicine, University of Sherbrooke,
Sherbrooke, Québec, Canada, J1H 5N4.
Very recently, we showed that NPY receptors are present in right ventricular endocardial
endothelial cells (EECs) and that the activation of these receptors modulate cytosolic and nuclear
Ca2+ in these cells. Also, it was reported in the literature that EECs isolated from the right
ventricle could be different than EECs isolated from the left ventricle. In this study, we wanted to
verify our hypothesis that not only NPY receptors are present in right ventricular EECs but also
NPY and that this peptide could be considered, like ET-1, as an endothelial-released factor. In
addition, a difference in NPY and NPY-induced excitation-secretion coupling could be different
in right compared to left ventricular EECs. Using 3-D confocal microscopy and
immunofluorescence as well as RIA, our results showed that NPY and NPY receptors densities
are different in right compared to left ventricular EECs. Also, our results showed that a difference
does exist in the sensitivity of each type of EECs to NPY. Furthermore, our results demonstrated
that only right ventricular EECs can release NPY and that NPY may modulate the excitationsecretion coupling of these cells. Thus, EECs could be considered as another important source of
circulating NPY as well as locally released NPY and this latter may highly contribute to
regulation of heart function and remodelling. This work was supported by the Canadian Institutes
of Health Research (CIHR).