Sodium-proton exchanger

Sodium-proton exchanger Sodium-proton antiport... 

Orlowski J (2004) Diversity of the mammalian sodium/ proton exchanger SLC9 gene family. Pflugers Arch -Eur J Physiol 447 549-565... 

Juel, C. (1988), Intracellular pH recovery and lactate efflux in mouse soleus muscles stimulated in vitro The involvement of sodium/proton exchange and a lactate carrier. Acta Physiol. Scand. 132,... 

Figure 11 Schematic of mucosal membrane sodium-proton exchanger and chloride-bicarbonate exchanger responsible for pH homeostasis in enterocyte cytosol. Microclimate pH is maintained by mucosal slowing of proton diffusion away from the lumenal membrane.

The characteristics of the four major classes of histamine receptors are summarized. Question marks indicate suggestions from the literature that have not been confirmed. AA, arachidonic acid DAG, diacylglycerol Iko,2+, calcium-activated potassium current IP3, inositol 1,4,5-trisphosphate NHE, sodium-proton exchange, PKC, protein kinase C NO, nitric oxide PTPLC, phosphoinositide-specific phospholipase C TXA2, thromboxane A2. Has brain-penetrating characteristics after systemic administration. 

Virkki, L. and M. Nikinmaa. 1993. Tributyltin inhibition of adrenergically activated sodium/proton exchange in erythrocytes os rainbow trout (Oncorhynchus mykiss). Aquat. Toxicol. 25 139-146. 

Further work found that the formation of acidic microdomains occurs at the stratum granulosum-SC interface and is regulated by the sodium-proton exchanger NHEl. In addition, the acidic SC surface is not fully developed at birth, and rather acidic microdomains at the SC-SG interface develop postnatally (Behne et al. 2003). Niesner et al. also used TP FLIM on artificial skin constructs and found that an identical pH gradient to that found in mammalian skin exists, which could enable further research on barrier function without the need for human or animal tissues (Niesner et al. 2005). 

Like the 5-HT1A receptor (see Section 2.1), the 5-HT2A receptor can regulate several transport processes. The 5-HT2A receptor activates the type 1 sodium-proton exchanger (NHE-1) in renal mesangial cells (187,227) and vascular smooth muscle cells (222), the Na+K+-AIPase (sodium pump) in airway smooth muscle cells (228), and the Na+/K+/2Cr cotransporter when 5-HT2A receptor transfected... 

Not all 5-HT4 receptor effects are mediated by cAMP. 5-HT4 receptors inhibit the sodium-proton exchanger isoforms NHE-2 and NHE-3 in human intestinal epithelial cells and T-84 cells through Src-dependent phosphorylation of PLC-y, elevation of intracellular Ca2+ levels, and subsequent activation of PKC-a (339). 5-HT4e receptors increase phosphoinositide hydrolysis in CHO cells (329). 5-HT4a receptors in neuroblastoma x glioma NIE-115 cells cause G13o, and RhoA-dependent neurite retraction and cell rounding. 

Gamovskaya MN, Mukhin Y, Raymond JR. Rapid activation of sodium-proton exchange and extracellular signal-regulated protein kinase in fibroblasts by G protein-coupled 5-HT1A receptor involves distinct signalling cascades. Biochem J 1998 330(Pt l) 489-495. 

Mukhin YV, Gamovskaya MN, Ullian ME, Raymond JR. ERK is regulated by sodium-proton exchanger in rat aortic vascular smooth muscle cells. J Biol Chem 2004 279 1845-1852. 

FIGURE 2.51 A mechanism for sodium chloride uptake, as explained in four steps of increasing complexity (a) The sodium/proton exchanger, (b) The sodium/proton exchanger with catalysis of add production by carbonic anhydrase. (c) The sodium/proton exchanger with catalysis of acid production and utilization of bicarbonate by the bicarbonale/chioride exchanger, (d) The finished model for transport of sodium and chloride ions. 

R.M. Mentzer Jr, Sodium-proton exchange inhibition to prevent coronary events in acute cardiac conditions trial, Paper presented at the American Heart Association Scientific Sessions. November 12, (2003). 

GIK, glucose-insulin-potassium solution AMI, acute myocardial infarction PTCA, percutaneous transluminal coronary angioplasty CABG, coronary artery bypass graft cariporide and enaporide are sodium/proton exchanger inhibitors N-acetyl-cysteine is an anti-oxidant agent. 

Tuominen A, Rissanen E, Bogdanova A, Nikinmaa M. 2003. Intracellular pH regulation in rainbow trout (Oncorhynchus mykiss)". Hypoxia stimulates sodium/proton exchange. J Comp Physiol B Biochem Syst Env Physiol 173 301-308. 

Response of Cell Volume to an Isosmotic Medium The Effect of Weak Acids and Bases on Cell Volume Ion Channels and their Effect on Cell Water The Sodium/Proton Exchanger... 

Figure 5a. Changes in cell pH when lymphocytes were suspended in isosmotic sodium propionate at pH 7.2. Only the sodium/proton exchangers were functional.

In this section, we will analyze an example of the physiological utility of two channels that have been discussed already the sodium/proton exchanger and the chloride/bicarbonate exchanger. Several mammalian cells use these channels to protect themselves against cell shrinkage due to increases in medium osmolality. To be consistent, we will continue to use the lymphocyte as our cell, recognizing that other cells may adopt different variations of these two channel mechanisms. 

Figure 7a. Changes in cell volume during regulatory volume decrease (RVD) followed by regulatory volume increase (RVI) in lymphocytes. Only sodium/proton exchangers were functional (square). Both sodium/proton exchangers and chloride/bi-carbonate exchangers were functional (diamond).

---