Search results for "hyperpolarization"
showing 4 items of 64 documents
Proton magnetic resonance imaging with para-hydrogen induced polarization.
2012
A major challenge in imaging is the detection of small amounts of molecules of interest. In the case of magnetic resonance imaging (MRI) their signals are typically concealed by the large background signal of e.g. the body. This problem can be tackled by hyperpolarization which increases the NMR signals up to several orders of magnitude. However, this strategy is limited for (1)H, the most widely used nucleus in NMR and MRI, because the enormous number of protons in the body screens the small amount of hyperpolarized ones. Here, we describe a method giving rise to high (1)H MRI contrast for hyperpolarized molecules against a large background signal. The contrast is based on the J-coupling i…
Analysis of the hyperpolarizing effects of forskolin in guinea-pig atrial heart muscle.
1988
The effects of forskolin on action potential configuration and on both uptake and efflux of 86Rb+ were studied in guinea-pig left atria. The action potential was prolonged by forskolin in the plateau range but shortened at the end of repolarization; maximal upstroke velocity and amplitude of slow response potentials were enhanced. In partially depolarized preparations, the resting potential was increased by forskolin; this effect was not prevented by atropine 1 μmol/1. Forskolin augmented the rate constant of 86Rb+ efflux in beating and in resting preparations. The uptake of 86Rbs+ was enhanced by forskolin in resting preparations. It is concluded that forskolin stimulates the Na+, K+ -pump…
Oxygen and glucose deprivation induces major dysfunction in the somatosensory cortex of the newborn rat
2005
The mechanisms and functional consequences of ischemia-induced injury during perinatal development are poorly understood. Subplate neurons (SPn) play a central role in early cortical development and a pathophysiological impairment of these neurons may have long-term detrimental effects on cortical function. The acute and long-term consequences of combined oxygen and glucose deprivation (OGD) were investigated in SPn and compared with OGD-induced dysfunction of immature layer V pyramidal cortical neurons (PCn) in somatosensory cortical slices from postnatal day (P)0-4 rats. OGD for 50 min followed by a 10-24-h period of normal oxygenation and glucose supply in vitro or in culture led to pron…
Cardiac pacemaker function of HCN4 channels in mice is confined to embryonic development and requires cyclic AMP.
2008
Important targets for cAMP signalling in the heart are hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels that underlie the depolarizing 'pacemaker' current, I(f). We studied the role of I(f) in mice, in which binding of cAMP to HCN4 channels was abolished by a single amino-acid exchange (R669Q). Homozygous HCN4(R669Q/R669Q) mice die during embryonic development. Prior to E12, homozygous and heterozygous embryos display reduced heart rates and show no or attenuated responses to catecholaminergic stimulation. Adult heterozygous mice display normal heart rates at rest and during exercise. However, following beta-adrenergic stimulation, hearts exhibit pauses and sino-atrial…