Nitric oxide is involved in the cardioprotection of neonatal rat hearts, but not in neonatal ischemic postconditioning.

The cardioprotective effect of ischemic preconditioning (IPC) and ischemic postconditioning (IPoC) in adult hearts is mediated by nitric oxide (NO). During the early developmental period, rat hearts exhibit higher resistance to ischemia-reperfusion (I/R) injury, contain higher levels of serum nitrates, and their resistance cannot be further increased by IPC or IPoC. NOS blocker (L-NAME) lowers their high resistance.

Possible role of mitochondrial K-ATP channel and nitric oxide in protection of the neonatal rat heart.

Cardioprotective effect of ischemic preconditioning (IPC) and ischemic postconditioning (IPoC) in adult hearts is mediated by mitochondrial-K-ATP channels and nitric oxide (NO). During early developmental period, rat hearts exhibit higher resistance to ischemia-reperfusion (I/R) injury and their resistance cannot be further increased by IPC or IPoC. Therefore, we have speculated, whether mechanisms responsible for high resistance of neonatal heart may be similar to those of IPC and IPoC.

Neonatal rat hearts cannot be protected by ischemic postconditioning.

Although there are abundant data on ischemic postconditioning (IPoC) in the adult myocardium, this phenomenon has not yet been investigated in neonatal hearts. To examine possible protective effects of IPoC, rat hearts isolated on days 1, 4, 7 and 10 of postnatal life were perfused according to Langendorff. Developed force (DF) of contraction was measured by an isometric force transducer.

Cardiac tolerance to ischemia in neonatal spontaneously hypertensive rats.

Hypertension is the risk factor of serious cardiovascular diseases, such as ischemic heart disease and atherosclerosis. The aim of the present study was to analyze the development of cardiac tolerance to ischemia in neonatal spontaneously hypertensive rats (SHR) and possible protective effect of ischemic preconditioning (IP) or adaptation to intermittent high-altitude hypoxia (IHAH). For this purpose we used 1- and 10-day-old pups of SHR and their normotensive control Wistar Kyoto rats (WKY).

Lipofuscin-like pigments in the rat heart during early postnatal development: effect of selenium supplementation.

The aim of the study was to characterize a) the lipofuscin-like pigment (LFP) accumulation (an indicator of ROS production) in the rat heart during early postnatal period and b) possible antioxidative role of selenium. Experimental animals received Na(2)SeO(3) in drinking water during gravidity and up to day 15 post partum. Two fluorophores of LFP in the hearts of 1-, 4-, 7- and 15-day-old rats were evaluated by fluorescent analysis.