Polyploidization of transplanted cardiac myocytes

Polyploidization of transplanted cardiac myocytes

Pieces of cardiac ventricuhu tissue of late embryonic or l-day postnatal rats, implanted beneath the kidney capsule of adult syngeneic hosts, formed viable, beating transplants. These transplants were investigated over a 40-day postoperative course. In the transplants, cellular binucleation and nuclear polyploidization occurred according to the same schedule as in the heart in situ. The composi...

Neonatal Rat Cardiac Myocytes

This study tested the hypothesis that the initiating mechanism is a major determinant of the response to calcium (Ca) accumulation in myocardium. Cultured neonatal rat ventriculocytes were exposed to Na', K+ pump inhibition with 1 mM ouabain and metabolic inhibition with 20 mM 2-deoxy--glucose and 1 mM cyanide (DOG-CN) for up to 2 h. Microspectrofluorometry of myocytes loaded with fura-2 showed...

Cardiac Myocytes and Mechanosensation

Calcium signaling in cardiac myocytes.

Calcium (Ca(2+)) is a critical regulator of cardiac myocyte function. Principally, Ca(2+) is the link between the electrical signals that pervade the heart and contraction of the myocytes to propel blood. In addition, Ca(2+) controls numerous other myocyte activities, including gene transcription. Cardiac Ca(2+) signaling essentially relies on a few critical molecular players--ryanodine recepto...

Metabolic Stress in Cardiac Myocytes

We have previously demonstrated coordinate inductions of c-fos, c-jun, jun B, and jun D in cardiac myocytes exposed to hypoxia for 2 to 4 hours. Induction of these transcripts occurred before any significant loss of intracellular ATP. In the present study, the origin of the signal(s) that regulates immediate-early gene induction was investigated by comparing the effects of hypoxia with those of...