Omega-3 polyunsaturated fatty acid-enriched diet differentially protects two subpopulations of myocardial mitochondria against Ca(2+)-induced injury.

Omega-3 polyunsaturated fatty acids (PUFA) confer protection against myocardial injury after ischemia-reperfusion. There are two subfractions of mitochondria located in different regions of the cell: subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM). The present study explored possible differences between Ca(2+)-induced mitochondrial swelling in rat SSM and IFM fractions under control conditions (control group [CG]) and after dietary supplementation with omega-3 PUFA (experimental group [EG]).

Reduced hyperpolarization of endothelial cells following high dietary Na+: effects of enalapril and tempol.

1. High dietary Na(+) is associated with impaired vascular endothelial function. However, the underlying mechanisms are not completely understood.

Endothelial dysfunction: Possible mechanisms and ways of correction.

Background: Endothelial function is impaired in atherosclerosis, hypertension, diabetes and aging, and this may be associated with an attenuated ability of endothelial cells to generate nitric oxide (NO).

Objectives: To evaluate possible alterations in endothelium-dependent relaxation in rat aortic rings, the activity of constitutive NO synthase and endothelial electrical responses to acetylcholine (Ach) in rat aorta, and the effect of one month of treatment with the angiotensin-converting enzyme inhibitor enalapril on endothelial function.

Methods: Endothelial membrane potential was measured in excised rat aorta using the perforated patch-clamp technique.

Na+-K+-ATPase is involved in the sustained ACh-induced hyperpolarization of endothelial cells from rat aorta.

Background And Purpose: Inhibition of Na(+)-K(+)-ATPase is known to attenuate endothelium-dependent relaxation in many arteries. The purpose of this study was to evaluate the role of Na(+)-K(+)-ATPase in the regulation of endothelial membrane potential at rest and during stimulation by ACh.

Experimental Approach: Membrane potential was recorded from the endothelium of rat aorta using the perforated patch-clamp technique.

Sodium-calcium exchanger contributes to membrane hyperpolarization of intact endothelial cells from rat aorta during acetylcholine stimulation.

1. The role of sodium-calcium exchanger in acetylcholine (Ach)-induced hyperpolarization of intact endothelial cells was studied in excised rat aorta. The membrane potential was recorded using perforated patch-clamp technique.

Differential properties of GABAergic synaptic connections in rat hippocampal cell cultures.

Based on the effect of prolonged tetanic stimulation (30 Hz, 4 sec), we divided GABAergic synaptic connections in hippocampal cell cultures into two groups: connections facilitated ( approximately 45%) and connections depressed ( approximately 55%) by the tetanic stimulation. In order to reveal possible reasons for the differential effect of the tetanization, we compared several properties of the connections belonging to both groups. We found that, on average, evoked IPSCs in the connections facilitated by the tetanization have a smaller amplitude and larger coefficient of variation (CV) of IPSC amplitude compared to connections depressed by the tetanization.

Human hypoxic ventilatory response with blood dopamine content under intermittent hypoxic training.

Adaptation to intermittent hypoxia can enhance a hypoxic ventilatory response (HVR) in healthy humans. Naturally occurring oscillations in blood dopamine (DA) level may modulate these responses. We have measured ventilatory response to hypoxia relative to blood DA concentration and its precursor DOPA before and after a 2-week course of intermittent hypoxic training (IHT).