Dear Sir : In their classic paper of 1960, Tosteson and Hoffman (13) provided the physiological basis for the HK/LK polymorphism of sheep erythrocytes (see Lauf (11 ] for a recent review). In their results, the function of the Na/K pump in HK sheep cells differed in one important respect from pumps in human red cells. Garrahan and Glynn (5) showed that human red cell pumps, in the absence of ex...

In this study, we examined whether nitric oxide synthase (NOS) is upregulated in small dorsal root ganglion (DRG) neurons after axotomy and, if so, whether the upregulation of NOS modulates Na(+) currents in these cells. We identified axotomized C-type DRG neurons using a fluorescent label, hydroxystilbamine methanesulfonate and found that sciatic nerve transection upregulates NOS activity in 6...

The blocking efficacy of 4,9-anhydro-TTX (4,9-ah-TTX) and TTX on several isoforms of voltage-dependent sodium channels, expressed in Xenopus laevis oocytes, was tested (Na(v1.2), Na(v1.3), Na(v1.4), Na(v1.5), Na(v1.6), Na(v1.7), and Na(v1.8)). Generally, TTX was 40-231 times more effective, when compared with 4,9-ah-TTX, on a given isoform. An exception was Na(v1.6), where 4,9-ah-TTX in nanomol...

A voltage-gated, small, persistent Na(+) current (I(Na)) has been shown in mammalian cardiomyocytes. Hypoxia potentiates the persistent I(Na) that may cause arrhythmias. In the present study, we investigated the effects of n-3 polyunsaturated fatty acids (PUFAs) on I(Na) in HEK-293t cells transfected with an inactivation-deficient mutant (L409C/A410W) of the alpha-subunit (hH1(alpha)) of human ...

Dehydration causes an increase in the sodium (Na) concentration and osmolarity of body fluid. For Na homeostasis of the body, controls of Na and water intake and excretion are of prime importance. However, the system for sensing the Na level within the brain that is responsible for the control of Na- and water-intake behavior remains to be elucidated. We reported previously that the Na(x) chann...

Na/K pump current was determined between -140 and +60 mV as steady-state, strophanthidin-sensitive, whole-cell current in guinea pig ventricular myocytes, voltage-clamped and internally dialyzed via wide-tipped pipettes. Solutions were designed to minimize all other components of membrane current. A device for exchanging the solution inside the pipette permitted investigation of Na/K pump curre...

The assessment of inflammatory markers and ions in exhaled breath condensate (EBC) is being utilized more frequently in diseases such as asthma and cystic fibrosis with marked variability in EBC measures, including those of exhaled Na(+). We sought to determine if variability in exhaled Na(+) was due to differences in pulmonary blood flow (PBF) or Na(+) in the mouth (salivary Na(+)). We measure...

Since the mechanism underlying the insulin stimulation of (Na+,K+)-ATPase transport activity observed in multiple tissues has remained undetermined, we have examined (Na+,K+)-ATPase transport activity (ouabain-sensitive 86Rb+ uptake) and Na+/H+ exchange transport (amiloride-sensitive 22Na+ influx) in differentiated BC3H-1 cultured myocytes as a model of insulin action in muscle. The active upta...

Gomes, Pedro, and Patrı́cio Soares-da-Silva. Upregulation of apical NHE3 in renal OK cells overexpressing the rodent 1-subunit of the Na pump. Am J Physiol Regul Integr Comp Physiol 290: R1142–R1150, 2006. First published November 17, 2005; doi:10.1152/ajpregu.00102.2005.— Vectorial Na reabsorption across the proximal tubule is mediated by apical entry of Na , primarily via Na /H exchanger isofo...