Na+/H+ antiporter plays an important role in mechanisms of the plant salt tolerance, it extrudes Na+ from cell energized by the proton gradient generated by the plasm membrane H(+)-ATPase and/or compartmentalizes Na+ in vacuole energized by the proton gradient generated by the vacuolar membrane H(+)-ATPase and H(+)-PPiase. This review mainly discusses the latest progress in the study of Na+/H+ antiporter in plant and yeast at molecular level.
Phylogeny ; Plants ; metabolism ; Salts ; metabolism ; Sodium ; metabolism ; Sodium-Hydrogen Exchangers ; classification ; metabolism ; Vacuoles ; physiology

Voltage-gated sodium channels are critical for the generation and conduction of nerve impulses. Recent studies show that in primary sensory neurons, the expression and dynamic regulation of several sodium channel subtypes play important roles in neuropathic pain. A number of SCN9A (encoding Nav1.7) gene point mutations are related with human genetic pain disorders. Transgenic and specific knockout techniques have revealed that Nav1.3, Nav1.8, Nav1.9 are important for the development and maintenance of neuropathic pain condition. Specific blockers of these sodium channels have been demonstrated to be effective in alleviating allodynia and hyperalgesia. Here we reviewed the roles of sodium channels in neuropathic pain, which may be applicable for the development of new drugs with enhanced efficacy for neuropathic pain treatment.
Animals ; Humans ; Neuralgia ; genetics ; metabolism ; physiopathology ; Neurons ; metabolism ; physiology ; Sodium Channels ; genetics ; metabolism ; physiology

Aquaporin belongs to a highly conserved group of membrane proteins called major intrinsic proteins (MIPs) that facilitate water transport across biological membranes. Aquaporins are membrane water channels that play critical roles in controlling the water content of cells and tissues. We focused on GhPIP1;2 which belongs to the PIP subfamily and GhgammaTIP1 which belongs to the gammaTIP group of the TIP subfamily. Northern blot analysis with gene-specific probes and real-time PCR demonstrated that GhPIP1;2 and GhgammaTIP1 are predominantly expressed during cotton fiber elongation, with the highest expression levels at 5 days post anthesis. The high and preferential expression of GhPIP1;2 and GhgammaTIP1 suggests that they may play important roles in supporting the rapid influx of water into vacuoles during cotton fiber cell expansion. Also, the effects of Ca2+ on aquaporins in salinity-stressed plants were studied. Researchers treated the protoplasts and plasma membrane with NaCl or CaCl2, alone or in combination. Under saline conditions, osmotic water permeability (Pf) values decreased in protoplasts and plasma membrane vesicles, and the same reduction was observed in the PIP1 aquaporin abundance, indicating inhibitory effects of NaCl on aquaporin functionality and protein abundance. Two different actions of Ca2+ were observed. Increase in free cytosolic calcium concentrations associated with stress perception may lead to aquaporin closure, however, the extra-calcium would lead to an upregulation of aquaporins. Meanwhile, experiments have demonstrated HvPIP2;1, one of barley aquaporins, has a higher water and CO2 transport activity. The goal of our plant aquaporin research is to determine the key aquaporin species responsible for water and CO2 transport, and to improve plant water relations, stress tolerance, CO2 uptake or assimilation, and plant productivity.
Aquaporins ; physiology ; Cell Enlargement ; Cotton Fiber ; Gossypium ; metabolism ; physiology ; Photosynthesis ; physiology ; Plant Proteins ; physiology ; Sodium Chloride ; pharmacology ; Stress, Physiological ; physiology

The Arabidopsis thaliana tonoplast Na+ /H+ antiporter gene, AtNHX1, was transferred into buckwheat by Agrobacterium-mediated method. Transgenic buckwheat plants were regenerated and selected on MS basal medium supplemented with 2.0mg/L 6-BA, 1.0mg/L KT, 0.lmg/L IAA, 50mg/L kanamycin and 500mg/L carbenicillin. 426 seedlings from 36 resistant calli originated from 864 explants (transformed about at 4.17 percentage) exhibited resistance to kanamycin. The transformants were confirmed by PCR, Southern blotting, RT-PCR and Northern blotting analysis. After stress treatment for 6 weeks with 200mmol/L NaCl, transgenic plants survived, while wild-type plants did not. After 3 days of stress treatment through different concentrations of NaCl, transgenic plants accumulated higher concentration of Na+ and proline than the control plants. However, the K+ concentration of transgenic plants declined in comparison with the control plants. Moreover, the rutin content of the roots, stems and leaves of transgenic buckwheat increased than those of the control plants. These results showed that it could be possible to improve the salt-tolerance of crops with genetic technology.
Adaptation, Physiological ; drug effects ; genetics ; physiology ; Arabidopsis Proteins ; genetics ; physiology ; Blotting, Northern ; Blotting, Southern ; Cation Transport Proteins ; genetics ; physiology ; Fagopyrum ; genetics ; metabolism ; physiology ; Plant Roots ; genetics ; metabolism ; physiology ; Plant Stems ; genetics ; metabolism ; physiology ; Plants, Genetically Modified ; genetics ; metabolism ; physiology ; Potassium ; metabolism ; Proline ; metabolism ; Regeneration ; Reverse Transcriptase Polymerase Chain Reaction ; Rutin ; metabolism ; Sodium ; metabolism ; Sodium Chloride ; pharmacology ; Sodium-Hydrogen Exchangers ; genetics ; physiology ; Transformation, Genetic

Na(+)-H(+) exchangers (NHE) are major membrane proteins that have been identified as signal transduction mediators in the regulation of cell differentiation and important membrane ion transporters in the regulation of the intercellular pH and the cell volume. NHE are composed of at least six isoforms and activated in growth factor-regulated cell differentiation. However, little is known about the differential regulation of NHE expression in the development. In the present study, we studied developmental regulation of the expression of NHE isoforms in human fetal tissues by comparing the expression of various isoforms between two developmental stages, i.e., week 11 (11 W) and week 16 (16 W). The results demonstrated that NHE1 transcripts were expressed ubiquitously. In comparison to the expression at 16 W, the level of NHE1 transcripts was low and varied significantly in a tissue-specific pattern at 11 W, suggesting that the house-keeping function of MHE1 occurs at 11 W or earlier and becomes well established at least as early as at 16 W. The tissue-specifically restricted expression of NHE2 and NHE3 was regulated at 11 W and 16 W in an opposite tendency, supporting the overlapping relationship between NHE2 and NHE3 in the tissue distribution as reported in adults. NHE5 expression was relatively ubiquitous at 11 W and became restricted in the cerebellum at 16 W, suggesting that the restrictive expression of NHE5 in the brain occurs later than that of other isoforms. The present study demonstrates a space time-dependent regulation of the tissue-specific expression pattern of NHE isoforms during human development between 11 W and 16 W. The results also suggest that at 16 W or earlier the expression pattern of developing tissues becomes similar to that of adult tissues. The observed developmental regulation of NHE expression provides a molecular basis for further study of the function and regulation of NHE gene during development.
Fetus ; embryology ; metabolism ; Gene Expression Regulation, Developmental ; physiology ; Humans ; Organ Specificity ; Protein Isoforms ; metabolism ; physiology ; RNA, Messenger ; metabolism ; physiology ; Sodium-Hydrogen Exchangers ; metabolism ; physiology ; Tissue Distribution

OBJECTIVEIn order to get the method for improving the salt resistance of Hedysarum polybotrys seeds and seedlings under different salt-alkaline stress, the seed germination and physiological characteristics of H. polybotrys seedlings were studied.

METHODSeveral physiological indexes of H. polybotrys seeds under different salt-alkaline stress, such as the germination vigor, germination rate, relative germination rate, relative salt damage rate were measured. And others indexes of the seedlings like chlorophyll contents, soluble protein contents, the permeability of plasmalemma, the activities of POD and SOD were also measured.

RESULTDifferent salt-alkaline stress decreased the germination rate, vigor of germinate, germination index, while relative salt damage rate increased. With the increased salt-alkaline concentration, the adverse effects became more obvious. The strength of the salts: Na2CO3 > Na2SO4 > NaCl. With the increase of the salt-alkaline concentration, the chlorophyll contents and the soluble protein contents decreased, but the permeability of plasmalemma increased. The change trend of SOD and POD activity was similar, it is increased firstly, and then decreased as the stress intensity extended, the most significant increase of Na2SO4 and Na2CO3 in the concentration of salt-alkaline was 25 mmol x L(-1), but NaCl was 50 mmol x L(-1).

CONCLUSIONThe seeds and seedlings inhibition of the salts was Na2CO3 > Na2SO4 > NaCl.

Alkalies ; metabolism ; Fabaceae ; growth & development ; metabolism ; physiology ; Seedlings ; growth & development ; metabolism ; physiology ; Seeds ; growth & development ; metabolism ; physiology ; Sodium Chloride ; metabolism ; Stress, Physiological

Cl(-) channel has been identified in heart over more than a decade. It is now known that Cl(-) channel is a super-family. The potentially important roles of cardiac Cl(-) channels have been emerging. Cardiac Cl(-) channels may play multifunctional roles in both physiological and pathophysiological conditions. Since the existence and distribution of cardiac Cl(-) channels vary with species and cardiac tissues, and blockade of Cl (-) channel with putative Cl(-) channel blockers or Cl(-) substitution has profound influence on cardiac electrical properties, it appears that the main role of cardiac Cl(-) channels may be to modulate cation channels or provide an ionic environment suitable for the activities of cation channels. So, to investigate the relationship between Cl(-) channels and cation channels may be of physiological and pathophysiological significance.
Animals ; Calcium Channels ; physiology ; Cations ; metabolism ; Chloride Channels ; physiology ; Heart ; physiology ; Humans ; Potassium Channels ; physiology ; Sodium Channels ; physiology ; TRPM Cation Channels ; physiology

AIMTo investigate the effect of hypoxia/early reoxygenation on persistent sodium current (I(Na.P)) in single ventricular myocytes of guinea pig and discuss its role and significance during this pathological condition.

METHODSThe whole cell patch clamp technology was used to record this current and study its change under the condition of hypoxia/reoxygenation model.

RESULTS(1) With 0.5 Hz, 1 Hz and 2 Hz pulse frequency, the current density gap between the first and the eighth pulse of I(Na.P) was (0.021 +/- 0.014) pA/ pF, (0.097 +/- 0.014) pA/pF and (0.133 +/- 0.024) pA/pF (P < 0.01) respectively. (2) Depolarization with membrane holding potential of -150 - -80 mV respectively, I(Na.P) density attenuated gradually. (3) The amplitude of I(Na.P) was increased consistently with the prolongation of hypoxia time during hypoxia. (4) I(Na.P) was (0.500 +/- 0.125) pA/pF, (1.294 +/- 0.321) pA/pF and (0.988 +/- 0.189) pA/pF (P < 0.01, vs normoxia, respectively) during normoxia, hypoxia after 15 min and reoxygenation after 5 min, respectively.

CONCLUSIONThese results indicate that I(Na.P) has great significance in arrhythmogenesis and calcium-overload, which causes the following postischemia and post hypoxia myocardial damage.

Animals ; Calcium ; metabolism ; Cell Hypoxia ; Guinea Pigs ; Heart Ventricles ; Membrane Potentials ; Myocytes, Cardiac ; metabolism ; physiology ; Oxygen ; metabolism ; Patch-Clamp Techniques ; Sodium ; metabolism ; Sodium Channels ; metabolism

Na+ -Ca2+ exchanger (NCX) transports Ca2+ coupled with Na+ across the plasma membrane in a bi-directional mode. Ca2+ flux via NCX mediates osteogenic processes, such as formation of extracellular matrix proteins and bone nodules. However, it is not clearly understood how the NCX regulates cellular Ca2+ movements in osteogenic processes. In this study, the role of NCX in modulating Ca2+ content of intracellular stores ([Ca2+](ER)) was investigated by measuring intracellular Ca2+ activity in isolated rat osteoblasts. Removal of extracellular Na+ elicited a transient increase of intracellular Ca2+ concentration ([Ca2+](i)). Pretreatment of antisense oligodeoxynucleotide (AS) against NCX depressed this transient Ca2+ rise and raised the basal level of [Ca2+](i). In AS-pretreated cells, the expression and activity of alkaline phosphatase (ALP), an osteogenic marker, were decreased. However, the cell viability was not affected by AS-pretreatment. Suppression of NCX activity by the AS-pretreatment decreased ATP-activated Ca2+ release from intracellular stores and significantly enhanced Ca2+ influx via store operated calcium influx (SOCI), compared to those of S-pretreated or control cells. These results strongly suggest that NCX has a regulatory role in cellular Ca2+ pathways in osteoblasts by modulating intracellular Ca2+ content.
Alkaline Phosphatase/metabolism ; Animals ; Calcium/*metabolism ; Cell Membrane/metabolism ; Cell Survival ; Cells, Cultured ; Cytoplasm/metabolism ; Endoplasmic Reticulum/metabolism ; Intracellular Space/metabolism ; Oligodeoxyribonucleotides, Antisense/pharmacology ; Osteoblasts/drug effects/*physiology ; Rats ; Signal Transduction ; Sodium/physiology ; Sodium-Calcium Exchanger/*physiology

OBJECTIVEIn order to get the method for improving the salt resistance of Lycium ruthenium seeds and seedlings under NaCl stress, the seed germination and physiological characteristics of L. ruthenium seedlings was studied.

METHODSeveral physiological indexes of L. ruthenium seeds under NaCl stress, such as the germination rate (Gr), germination vigor (Gv), germination index (Gi), vigor index (Vi), and relative salt damage rate were measured. Other indexes of the seedlings like relative water contents (RWC) , chlorophyll contents, soluble protein contents, electrolyte leakage, the contents of malondialdehyde (MDA), and peroxidase (POD) were also measured.

RESULTNaCl at lower concentration could promote the seed germination but inhibit the seed germination at higher concentration. After the treatment by CaCl2 at the different concentrations, all germination indexes were increased. With the increase of salt concentration, the relative water contents and the contents of chlorophyll were decreased, the content of MDA and electrolyte leakage were increased. The change trend of POD activity showed the first increase and then decrease with the increase of salt concentration, which was similar to that of the soluble protein. After the treatment by CaCl2, relative water contents, chlorophyll and POD activities were decreased more slowly, and also electrolyte leakage and MDA contents increased slowly.

CONCLUSIONThe CaCl2 could significantly alleviate the damages to the seeds and seedlings of L. ruthenium under NaCl stress, and promote the salt resistance to the seeds and seedlings of L. ruthenium.

Calcium ; pharmacology ; Germination ; drug effects ; Lycium ; drug effects ; metabolism ; physiology ; Seedlings ; drug effects ; metabolism ; physiology ; Seeds ; drug effects ; metabolism ; physiology ; Sodium Chloride ; metabolism