Hyperpolarization Researches with Parahydrogen

Shim, Joongmoo,Jeong, Keunhong 한국자기공명학회 2018 Journal of the Korean Magnetic Resonance Society Vol.22 No.1

Among several NMR hyperpolarization techniques, parahydrogen-based hyperpolarization technique is recently extensively utilized to enhance the sensitivity of the conventional NMR/MRI spectroscopy. Two mostly investigated research topics are PHIP (Parahydrogen Induced Polarization) and SABRE (Signal Amplification By Reversible Exchange), which are commonly using the parahydrogen as the source of hyperpolarization. Those researches have been considered as the promising techniques that could provide hyperpolarized states on the ambient substrates including biologically important materials. Therefore, based on their potentials, we briefly reviewed several important experimental results on those topics after introducing the basic principle of parahydrogen and its generation with conceptual explanations. We hope this review will broaden the parahydrogen-based hyperpolarization transfer study on many researches in Korea.

Hyperpolarization Researches with Parahydrogen

심중무,정근홍 한국자기공명학회 2018 Journal of the Korean Magnetic Resonance Society Vol.22 No.1

Among several NMR hyperpolarization techniques, parahydrogen-based hyperpolarization technique is recently extensively utilized to enhance the sensitivity of the conventional NMR/MRI spectroscopy. Two mostly investigated research topics are PHIP (Parahydrogen Induced Polarization) and SABRE (Signal Amplification By Reversible Exchange), which are commonly using the parahydrogen as the source of hyperpolarization. Those researches have been considered as the promising techniques that could provide hyperpolarized states on the ambient substrates including biologically important materials. Therefore, based on their potentials, we briefly reviewed several important experimental results on those topics after introducing the basic principle of parahydrogen and its generation with conceptual explanations. We hope this review will broaden the parahydrogen -based hyperpolarization transfer study on many researches in Korea.

The ALTADENA and PASADENA studies in benchtop NMR spectrometer

So, Howon,Jeong, Keunhong 한국자기공명학회 2019 Journal of the Korean Magnetic Resonance Society Vol.23 No.1

Parahydrogen induced hyperpolarization (PHIP) technique is extensively studied to increase the sensitivity of the conventional NMR spectroscopy and recently try to apply this advanced technique into the revolutionary future of the MRI. The other hyperpolarization technique, which is widely utilized, is DNP (Dynamic Nuclear Polarization)-based hyperpolarization one. Despite its great advances in these fields, it contains several drawbacks to overcome: fast relaxation time, expensive equipment is needed, long build-up time is required (several hours), and batch scale material is hyperpolarized. To overcome all those limitations, one can effectively harness the hyperpolarized spin state of parahydrogen. One important step for utilizing the spin state of parahydrogen is doing well-developed experiments of ALTADENA and PASADENA. Based on those concepts, we successfully obtain the hydrogenation signals of ALTADENA and PASADENA from styrene by using benchtop NMR spectrometer. Also those signals were conceptually analyzed and confirmed with different mechanisms. To our best knowledge, those experiments using 1.4T (benchtop NMR) is the first reported one. Considering these experiments, we hope that parahydrogen-based hyperpolarization transfer studies in NMR/MRI will be broadened in Korea in the future.

The ALTADENA and PASADENA studies in benchtop NMR spectrometer

소호원,정근홍 한국자기공명학회 2019 Journal of the Korean Magnetic Resonance Society Vol.23 No.1

Parahydrogen induced hyperpolarization (PHIP) technique is extensively studied to increase the sensitivity of the conventional NMR spectroscopy and recently try to apply this advanced technique into the revolutionary future of the MRI. The other hyperpolarization technique, which is widely utilized, is DNP (Dynamic Nuclear Polarization)-based hyperpolarization one. Despite its great advances in these fields, it contains several drawbacks to overcome: fast relaxation time, expensive equipment is needed, long build-up time is required (several hours), and batch scale material is hyperpolarized. To overcome all those limitations, one can effectively harness the hyperpolarized spin state of parahydrogen. One important step for utilizing the spin state of parahydrogen is doing well-developed experiments of ALTADENA and PASADENA. Based on those concepts, we successfully obtain the hydrogenation signals of ALTADENA and PASADENA from styrene by using benchtop NMR spectrometer. Also those signals were conceptually analyzed and confirmed with different mechanisms. To our best knowledge, those experiments using 1.4T (benchtop NMR) is the first reported one. Considering these experiments, we hope that parahydrogen-based hyperpolarization transfer studies in NMR/MRI will be broadened in Korea in the future.

Hyperpolarization: Sensitivity Boost in Magnetic Resonance Spectroscopy and Imaging

고혜지,공경현,정기진,최익장,서형림,이영복 한국자기공명학회 2015 Journal of the Korean Magnetic Resonance Society Vol.19 No.3

Hyperpolarization methods are the most emerging techniques in the field of magnetic resonance (MR) researches since they make a contribution to overcoming sensitivity limitation of MR spectroscopy and imaging, leading to new fields of researches, real-time in vivo metabolic/molecular imaging and MR analysis of chemical/biological reactions in non-equilibrium conditions. Make use of enormous signal enrichments, it becomes feasible to investigate various chemical and biochemical systems with low γ nuclei in real-time. This review deals with the theoretical principals of common hyperpolarization methods and their experimental features. In addition, more detailed theories, mechanisms, and applications of dissolution dynamic nuclear polarization (D-DNP) are discussed.

Hyperpolarization: Sensitivity Boost in Magnetic Resonance Spectroscopy and Imaging

Ko, Hyeji,Gong, Gyeonghyeon,Jeong, Gijin,Choi, Ikjang,Seo, Hyeonglim,Lee, Youngbok Korean Magnetic Resonance Society 2015 Journal of the Korean Magnetic Resonance Society Vol.19 No.3

Hyperpolarization methods are the most emerging techniques in the field of magnetic resonance (MR) researches since they make a contribution to overcoming sensitivity limitation of MR spectroscopy and imaging, leading to new fields of researches, real-time in vivo metabolic/molecular imaging and MR analysis of chemical/biological reactions in non-equilibrium conditions. Make use of enormous signal enrichments, it becomes feasible to investigate various chemical and biochemical systems with low ${\gamma}$ nuclei in real-time. This review deals with the theoretical principals of common hyperpolarization methods and their experimental features. In addition, more detailed theories, mechanisms, and applications of dissolution dynamic nuclear polarization (D-DNP) are discussed.

세포 밖 2가 양이온이 과분극에 의해 활성화되는 전류(Ih)에 미치는 영향

곽지연(Jiyeon Kwak) 대한약학회 2012 약학회지 Vol.56 No.2

The hyperpolarization-activated current (Ih) is an inward cation current activated by hyperpolarization of the membrane potential and plays a role as an important modulator of action potential firing frequency in many excitable cells. In the present study we investigated the effects of extracellular divalent cations on Ih in dorsal root ganglion (DRG) neurons using whole-cell voltage clamp technique. Ih was slightly increased in Ca2+-free bath solution. BAPTA-AM did not change the amplitudes of Ih. Amplitudes of Ih were decreased by Ca2+, Mg2+ and Ba2+ dose-dependently and voltage-independently. Inhibition magnitudes of Ih by external divalent cations were partly reversed by the concomitant increase of extracellular K+ concentration. Reversal potential of Ih was significantly shifted by Ba2+ and V1/2 was significantly affected by the changes of extracellular Ca2+ concentrations. These results suggest that Ih is inhibited by extracellular divalent cations (Ca2+, Mg2+ and Ba2+) by interfering ion influxes in cultured rat DRG neurons.

Acetylcholine Induces Hyperpolarization Mediated by Activation of $K_{(ca)}$ Channels in Cultured Chick Myoblasts

Lee, Do-Yun,Han, Jae-Hee,Park, Jae-Yong The Korean Society of Pharmacology 2005 The Korean Journal of Physiology & Pharmacology Vol.9 No.1

Our previous report demonstrated that chick myoblasts are equipped with $Ca^{2+}$-permeable stretchactivated channels and $Ca^{2+}-activated$ potassium channels ($K_{Ca}$), and that hyperpolarization-induced by $K_{Ca}$ channels provides driving force for $Ca^{2+}$ influx through the stretch-activated channels into the cells. Here, we showed that acetylcholine (ACh) also hyperpolarized the membrane of cultured chick myoblasts, suggesting that nicotinic acetylcholine receptor (nAChR) may be another pathway for $Ca^{2+}$ influx. Under cell-attatched patch configuration, ACh increased the open probability of $K_{Ca}$ channels from 0.007 to 0.055 only when extracellular $Ca^{2+}$ was present. Nicotine, a nAChR agonist, increased the open probability of $K_{Ca}$ channels from 0.008 to 0.023, whereas muscarine failed to do so. Since the activity of $K_{Ca}$ channel is sensitive to intracellular $Ca^{2+}$ level, nAChR seems to be capable of inducing $Ca^{2+}$ influx. Using the $Ca^{2+}$ imaging analysis, we were able to provide direct evidence that ACh induced $Ca^{2+}$ influx from extracellular solution, which was dramatically increased by valinomycin-mediated hyperpolarization. In addition, ACh hyperpolarized the membrane potential from $-12.5{\pm}3$ to $-31.2{\pm}5$ mV by generating the outward current through $K_{Ca}$ channels. These results suggest that activation of nAChR increases $Ca^{2+}$ influx, which activates $K_{Ca}$ channels, thereby hyperpolarizing the membrane potential in chick myoblasts.

Acetylcholine Induces Hyperpolarization Mediated by Activation of K<SUB>(Ca)</SUB> Channels in Cultured Chick Myoblasts

Doyun Lee,Jaehee Han,Jae-Yong Park 대한생리학회-대한약리학회 2005 The Korean Journal of Physiology & Pharmacology Vol.9 No.1

Our previous report demonstrated that chick myoblasts are equipped with Ca<SUP>2⁢</SUP>-permeable stretch- activated channels and Ca<SUP>2⁢</SUP>-activated potassium channels (K<SUB>Ca</SUB>), and that hyperpolarization-induced by K<SUB>Ca</SUB> channels provides driving force for Ca<SUP>2⁢ </SUP>influx through the stretch-activated channels into the cells. Here, we showed that acetylcholine (ACh) also hyperpolarized the membrane of cultured chick myoblasts, suggesting that nicotinic acetylcholine receptor (nAChR) may be another pathway for Ca<SUP>2⁢</SUP> influx. Under cell-attatched patch configuration, ACh increased the open probability of K<SUB>Ca</SUB> channels from 0.007 to 0.055 only when extracellular Ca<SUP>2⁢</SUP> was present. Nicotine, a nAChR agonist, increased the open probability of K<SUB>Ca</SUB> channels from 0.008 to 0.023, whereas muscarine failed to do so. Since the activity of K<SUB>Ca</SUB> channel is sensitive to intracellular Ca<SUP>2⁢</SUP> level, nAChR seems to be capable of inducing Ca<SUP>2⁢</SUP> influx. Using the Ca<SUP>2⁢</SUP> imaging analysis, we were able to provide direct evidence that ACh induced Ca<SUP>2⁢</SUP> influx from extracellular solution, which was dramatically increased by valinomycin-mediated hyperpolarization. In addition, ACh hyperpolarized the membrane potential from ⁣12.5⁑3 to ⁣31.2⁑5 mV by generating the outward current through K<SUB>Ca</SUB> channels. These results suggest that activation of nAChR increases Ca<SUP>2⁢</SUP> influx, which activates K<SUB>Ca</SUB> channels, thereby hyperpolarizing the membrane potential in chick myoblasts.

The Inhibitory Effect of Opioid on the Hyperpolarization-Activated Cation Currents in Rat Substantia Gelatinosa Neurons

Seol, Geun-Hee,Kim, Jun,Cho, Sun-Hee,Kim, Won-Ki,Kim, Jong-Whan,Kim, Sang-Jeong The Korean Society of Pharmacology 2001 The Korean Journal of Physiology & Pharmacology Vol.5 No.5

The action of opioid on the hyperpolarization-activated cation current $(I_h)$ in substantia gelatinosa neurons were investigated by using whole-cell voltage-clamp recording in rat spinal brain slices. Hyperpolarizing voltage steps revealed slowly activating currents in a subgroup of neurons. The half-maximal activation and the reversal potential of the current were compatible to neuronal $I_h.$ DAMGO $(1\;{\mu}M),$ a selective- opioid agonist, reduced the amplitude of $I_h$ reversibly. This reduction was dose-dependent and was blocked by CTOP $(2\;{\mu}M),$ a selective ${\mu}-opioid$ antagonist. DAMGO shifted the voltage dependence of activation to more hyperpolarized potential. Cesium (1 mM) or ZD 7288 $(100\;{\mu}M)$ blocked $I_h$ and the currents inhibited by cesium, ZD 7288 and DAMGO shared a similar time and voltage dependence. These results suggest that activation of ${\mu}-opioid$ receptor by DAMGO can inhibit $I_h$ in a subgroup of rat substantia gelatinosa neurons.