Low oxygen in inspired air causes severe cerebrocortical hypoxia and cell death in the cerebral cortex of awake rats.

Type 1 respiratory failure (T1RF) is associated with secondary acute brain injury (sABI). The underlying mechanisms of sABI could include injury to brain cells mediated either by hypoxia or by lung injury-triggered inflammation. To elucidate to what extent T1RF causes hypoxia and a consequent hypoxic injury in the brain in the absence of lung injury, we exposed healthy, conscious Sprague-Dawley rats to 48 h long low partial pressure of O in inspired air (PiO) (7.

Effect of thermal preconditioning on Hsp70 expression in the medulla oblongata and on hemodynamics during passive hyperthermia.

A short-term episode of elevated core body temperature that induces Hsp70 expression (thermal preconditioning) may protect against heatstroke during subsequent hyperthermia. The protective effects of thermal preconditioning may involve several cellular and immunological mechanisms and improvements in baroreflex sensitivity. To substantiate the hypothesis that the protective effect of thermal preconditioning also occurs in conditions with intact thermoregulation, we examined the evolution of spontaneous cardiovagal baroreflex sensitivity and the protective effect of Hsp70 expression after thermal preconditioning in nonanesthetized Wistar-Kyoto rats with implanted telemetric transmitters.

Biphasic changes in spontaneous cardiovagal baroreflex sensitivity during passive hyperthermia.

Successful adaptation to passive hyperthermia requires continual adjustment of circulation, which is mediated mainly by the autonomic nervous system. The goal of this study was to explore the alterations in spontaneous cardiovagal baroreflex sensitivity (BRS) during exposure to a hot environment. To continuously follow changes in core body temperature (Tc), haemodynamics, and BRS, male Wistar-Kyoto rats were implanted with telemetric transmitters.

Rat astrocytes during anoxia: Secretome profile of cytokines and chemokines.

Introduction: The precise mechanisms of the inflammatory responses after cerebral ischemia in vivo are difficult to elucidate because of the complex nature of multiple series of interactions between cells and molecules. This study explored temporal patterns of secretion of 30 cytokines and chemokines from Sprague Dawley rat astrocytes in primary culture in order to elucidate signaling pathways that are triggered by astrocytes during anoxia.

Methods: Primary cultures of rat brain astrocytes were incubated for periods of 2-24 hr in the absence of oxygen (anoxia) or under normal partial pressure of oxygen (controls).

Wistar rats resistant to the hypertensive effects of ouabain exhibit enhanced cardiac vagal activity and elevated plasma levels of calcitonin gene-related peptide.

Ouabain is a cardiac glycoside produced in the adrenal glands and hypothalamus. It affects the function of all cells by binding to Na+/K+-ATPase. Several lines of evidence suggest that endogenous ouabain could be involved in the pathogenesis of essential (particularly, salt-sensitive) hypertension.

Biphasic dose-dependent modulation of cardiac parasympathetic activity by moxonidine, an imidazoline I1-receptor agonist.

Peripheral beta-adrenergic blockade and activation of central alpha2-adrenergic receptors have parasympathomimetic effects. The impact of activation of central imidazoline I1-receptors on vagal activity is not yet clear, but there is some evidence that imidazoline I1-receptors agonists may inhibit the parasympathetic system. Parasympatholytic effects may represent a risk for patient with reduced parasympathetic activity.

Tedisamil attenuates foetal transformation of myosin in the hypertrophied rat myocardium.

1 Reduction in repolarizing potassium currents has controversial effects on hypertrophic responses in cardiomyocytes of transgenic models and cultured cardiomyocytes. It remains thus unknown whether a blockade of potassium channels with tedisamil (N,N'dicyclopropylmethylene-9,9-tetramethylene-3,7-diazabicyclo(3.3.

Propentofylline rapidly normalizes mitochondrial respiration in a gerbil low flow unilateral forebrain ischemia.

The effect of propentofylline on mitochondrial respiratory activity was assessed in gerbils after 30 min of unilateral forebrain ischemia and 5 min of incomplete reperfusion. Cerebral blood flow (CBF) measured by hydrogen clearance was reduced to 12.6+/-2.