The Alkali and Alkaline Earth Metals

Akitt, J. W.

doi:10.1007/978-1-4613-1783-8_7

Cited by 21 publications

(17 citation statements)

References 185 publications

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“…Lithium-7 behaves substantially differently from 23 Na (22). Lithium-7 is weakly quadrupolar, with a quadrupole coupling constant (QCC) in the ionic environment of about 85 kHz.…”

Section: Discussionmentioning

confidence: 98%

“…Although 7 Li is also spin-3/2, its spin relaxation is only weakly quadrupolar (22). This substantially alters the nature of any biexponential relaxation, and makes its detection problematic (see below).…”

Section: Discussionmentioning

confidence: 99%

“…Although 7 Li is also spin-3/2, its spin relaxation is only weakly quadrupolar (22). Intrinsic biexponential T 2 relaxation has not been clearly observed for 7 Li in biological systems (13,15).…”

mentioning

confidence: 97%

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Estimating intracellular lithium in brain in vivo by localized ⁷Li magnetic resonance spectroscopy

Komoroski

Pearce

2008

Magnetic Resonance in Med

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The therapeutic mechanism of action of lithium (Li) in bipolar disorder is unknown. While Li is presumed to work intracellularly in the brain, the fraction of intracellular Li in the brain in vivo is not known. It has not yet been possible to determine, directly and noninvasively, the intra-to extracellular distribution of Li in human brain in vivo. Lithium-7 ( 7 Li) MR is the only technique available for measuring noninvasively the concentration of Li in the brain in vivo. Here the individual components of biexponential 7 Li transverse (T 2 ) relaxation in rat brain in vivo are identified with intra-and extracellular Li, and used to estimate its compartmental distribution. Intracellular T 2 was 14.6 ؎ 6.9 ms, while extracellular T 2 was 160 ؎ 52 ms in nine rats. The fraction of intracellular brain Li ranged from 37% to 75% (mean: 63 ؎ 11%). Further, the biexponential T 2 results provided the basis for estimating Li compartmental distribution from monoexponential T 2 decays using a simple linear approximation. Lithium (Li) is an elemental cation used in the treatment of bipolar disorder. Despite its widespread use in clinical settings and extensive research into its mechanisms of action, there is still little agreement as to how Li exerts its clinical effects (1,2). Because Li is a simple ion, it must be viewed differently than other psychoactive drugs, which are usually organic compounds with clear receptor binding properties. Li competes with endogenous cations and thereby affects a wide range of biochemical processes, neurotransmitter synthesis and release, and cell membranes (3). Considerable attention has been focused on the effects of Li on phosphoinositide second-messenger metabolism (4 -6). But other possible mechanisms, including the effects on G-proteins (7), Na, K-adenosine triphosphatase (8), glycogen synthase kinase-3 (6,9), and gene expression (9 -11) are under investigation. Because most biochemical processes, including phosphoinositide second-messenger metabolism, occur within the cell, it is often presumed that Li exerts its clinically relevant effects in the intracellular space of neurons in the brain. However, because low intracellular Li concentrations have been found in some in vitro cellular systems, it has been suggested that the mechanism of action may be, at least in part, extracellular (12). The typical therapeutic serum concentration is 0.6 -1.2 mM. While the overall brain concentration is generally in the same range as the serum concentration (13-15), the fraction of intracellular Li in the brain in vivo is not known. Consequently, from a mechanistic point of view, the ratio of intracellular to extracellular Li in brain in vivo is an important parameter to measure because doing so may reveal how Li exerts its therapeutic effects.NMR has been widely used to measure cationic distribution in cellular preparations. Because most alkali-metal chemical shifts are relatively insensitive to the ionic environment, the intra-and extracellular resonances typically occur at the same chemical shift...

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“…Lithium-7 behaves substantially differently from 23 Na (22). Lithium-7 is weakly quadrupolar, with a quadrupole coupling constant (QCC) in the ionic environment of about 85 kHz.…”

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

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Estimating intracellular lithium in brain in vivo by localized ⁷Li magnetic resonance spectroscopy

Komoroski

Pearce

2008

Magnetic Resonance in Med

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“…Lithium-7 has NMR properties and behavior substantially different from those of 23 Na or 39 K (18). Whereas 23 Na and 39 K relax totally and strongly by the quadrupolar mechanism, 7 Li is only weakly quadrupolar.…”

Section: Visibility In Vivomentioning

confidence: 91%

“…Whereas 23 Na and 39 K relax totally and strongly by the quadrupolar mechanism, 7 Li is only weakly quadrupolar. This derives from the small quadrupole moment and Sternheimer antishielding factor of the Li ϩ cation (18). The Sternheimer antishielding factor is a measure of the effective electric field gradient at the nucleus from electron polarization caused by exposure of the cation to an external electric field gradient, such as with cation binding to a macromolecular site.…”

Section: Visibility In Vivomentioning

confidence: 99%

Lithium Visibility in Rat Brain and Musclein Vivoby7Li NMR Imaging

Komoroski

Pearce

Newton

1998

Journal of Magnetic Resonance

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Solid‐StateNMRof the Light Main Group Metals

Schurko

Jaroszewicz

2015

Encyclopedia of Inorganic and Bioinorganic Chemistry

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This review article discusses solid‐state nuclear magenetic resonance (SSNMR) spectroscopy of NMR‐active isotopes of the light main group metals, including lithium ( 6 Li and 7 Li), sodium ( 23 Na), aluminum ( 27 Al), potassium ( 39 K), magnesium ( 25 Mg), calcium ( 43 Ca), and beryllium ( 9 Be). All of these nuclides are quadrupolar, meaning that they have nuclear spins greater than 1/2. As a result, specialized techniques are needed to effectively acquire their spectra, which can then be analyzed to provide information on molecular‐level structure and dynamics. Work on SSNMR of 7 Li, 23 Na, and 27 Al, which are all receptive nuclides, has been essential in the development of a wide range of pulse sequences and techniques for acquiring good quality, high‐resolution SSNMR spectra. Applications of 7 Li, 23 Na, and 27 Al SSNMR are widespread, owing to the ubiquity of these elements in both natural and manmade materials. 25 Mg, 39 K, 43 Ca, and 9 Be are relatively unreceptive nuclides by comparison (the former three are low‐γ nuclides); however, much work has gone into both development of spectral acquisition methods and application of these methods to study a wide range of systems. This review article, which is directed at non‐NMR experts and/or students, provides a basic background to SSNMR of quadrupolar nuclides, and then discusses key reviews and papers which are essential for understanding the scope and potential of SSNMR of metal nuclides.

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The Alkali and Alkaline Earth Metals

Cited by 21 publications

References 185 publications

Estimating intracellular lithium in brain in vivo by localized ⁷Li magnetic resonance spectroscopy

Estimating intracellular lithium in brain in vivo by localized ⁷Li magnetic resonance spectroscopy

Lithium Visibility in Rat Brain and Musclein Vivoby7Li NMR Imaging

Solid‐StateNMRof the Light Main Group Metals

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The Alkali and Alkaline Earth Metals

Cited by 21 publications

References 185 publications

Estimating intracellular lithium in brain in vivo by localized 7Li magnetic resonance spectroscopy

Estimating intracellular lithium in brain in vivo by localized 7Li magnetic resonance spectroscopy

Lithium Visibility in Rat Brain and Musclein Vivoby7Li NMR Imaging

Solid‐StateNMRof the Light Main Group Metals

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Estimating intracellular lithium in brain in vivo by localized ⁷Li magnetic resonance spectroscopy

Estimating intracellular lithium in brain in vivo by localized ⁷Li magnetic resonance spectroscopy