Frontiers in physiology
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Frontiers in physiology · Jan 2014
ReviewNeural reflex regulation of systemic inflammation: potential new targets for sepsis therapy.
Sepsis progresses to multiple organ dysfunction due to the uncontrolled release of inflammatory mediators, and a growing body of evidence shows that neural signals play a significant role in modulating the immune response. Thus, similar toall other physiological systems, the immune system is both connected to and regulated by the central nervous system. The efferent arc consists of the activation of the hypothalamic-pituitary-adrenal axis, sympathetic activation, the cholinergic anti-inflammatory reflex, and the local release of physiological neuromodulators. ⋯ Despite cytokine receptor expression in vagal afferent fibers, pro-inflammatory cytokines have no significant effect on vagus nerve activity. Thus, the CB may be the source of immunosensory inputs and incoming neural signals and, in fact, sense inflammatory mediators, playing a protective role during sepsis. Considering that CB stimulation increases sympathetic activity and adrenal glucocorticoids release, the electrical stimulation of arterial chemoreceptors may be suitable therapeutic approach for regulating systemic inflammation.
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Frontiers in physiology · Jan 2014
Effects of aging on the association between cerebrovascular responses to visual stimulation, hypercapnia and arterial stiffness.
Aging is associated with decreased vascular compliance and diminished neurovascular- and hypercapnia-evoked cerebral blood flow (CBF) responses. However, the interplay between arterial stiffness and reduced CBF responses is poorly understood. It was hypothesized that increased cerebral arterial stiffness is associated with reduced evoked responses to both, a flashing checkerboard visual stimulation (i.e., neurovascular coupling), and hypercapnia. ⋯ In conclusion, older subjects had reduced neurovascular- and hypercapnia-mediated CBF responses. Furthermore, lower hypercapnia-mediated blood flow responses through the MCA were associated with increased vascular stiffness. These findings suggest the reduced hypercapnia-evoked CBF responses through the MCA, in older individuals may be secondary to vascular stiffening.
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Frontiers in physiology · Jan 2014
Effect of phenylephrine vs. ephedrine on frontal lobe oxygenation during caesarean section with spinal anesthesia: an open label randomized controlled trial.
During caesarean section spinal anesthesia may provoke maternal hypotension that we prevent by administration of phenylephrine and/or ephedrine. Phenylephrine is however reported to reduce the near infrared spectroscopy-determined frontal lobe oxygenation (ScO2) but whether that is the case for patients exposed to spinal anesthesia is not known. ⋯ In the choice between phenylephrine and ephedrine for maintenance of blood pressure during caesarean section with spinal anesthesia, ephedrine maintains frontal lobe oxygenation and maternal heart rate with a similar increase in fetal heart rate as elicited by phenylephrine.
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Frontiers in physiology · Jan 2014
Preserved frontal lobe oxygenation following calcium chloride for treatment of anesthesia-induced hypotension.
Vasopressor agents may affect cerebral oxygenation (rScO2) as determined by near-infrared spectroscopy on the forehead. This case series evaluated the effect of calcium chloride vs. α and β-adrenergic receptor agonists on rScO2 in patients (n = 47) undergoing surgery during i.v. anesthesia. ⋯ Following administration of β-adrenergic agents and calcium chloride rScO2 was preserved while after administration of α-adrenergic drugs rScO2 was reduced by app. 2% (P < 0.05). Following α-adrenergic drugs to treat anesthesia-induced hypotension tissue oxygenation is reduced while the use of β-adrenergic agonists and calcium chloride preserve tissue oxygenation.