Than the currents of comparable cells measured in ND (e.g circle at mV in Fig.A).As an example, HOinjected cells exhibited an average membrane conductance of �� ��S (n ) in NDNMDG (Fig.D) compared with an average membrane conductance of .�� .��S (n ) in ND (Fig.D), even though the distinction will not accomplish statistical significance in our information set (P n , onetailed unpaired ttest).Application of mM HCO inside the continued absence of Napresence of NMDG did not elicit a rise in outwardly directed currents, which would have indicated the net, inward action of an electrogenic cation, HCO cotransporter.Actually, for all 3 groups of injected oocytes, the addition of mM HCO in PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/21334000 the continued absence of Na (squares) reduced the conductance amongst mV and mV (Fig.A�CD).On the other hand, for oocytes expressing human NBCeAEGFP (Fig.B) or rabbit NBCeA (Fig.C), the application of COHCO elevated the magnitude of inwardly directed currents (squares), which likely represent electrogenic Na HCO efflux, supported by intracellular Na and HCO.The presence of NBCeA activity in oocytes injected with human NBCeAEGFP or rabbit NBCeA cRNA was confirmed by replacing NMDG with Na within the continued presence of HCO (diamonds).This maneuver elicited substantial Na and HCOdependent currents in these cells (Fig B�CD), but not in HOinjected oocytes (Fig A and D).Therefore, neither human NBCeAEGFP nor rabbit NBCeA exhibit detectable electrogenic NMDGHCO BGT226 Solvent cotransport activity in oocytes.Lithium.We superfused oocytes with our NDLi, mM HCOLi, and mM HCO options (Table) in sequence, and after that performed the voltageclamp protocol.In HOinjected oocytes, Vm didn’t adjust instantaneously in response to either resolution transform.Nevertheless, application of COHCO within the presence of Li induced a fast hyperpolarization in oocytes expressing human NBCeAEGFP (��Vm �� mV, n , not shown) and in oocytes expressing rabbit NBCeA (��Vm �� mV, n , not shown).Subsequently, replacing Li with Na within the superfusion option elicited hyperpolarizations of even greater magnitude ��Vm �� mV for human NBCeAEGFP (n , not shown) and ��Vm �� mV for rabbit NBCeA (n , not shown).Figure , A�CC shows representative IV relationships for oocytes injected with HO or with cRNA encoding human NBCeAEGFP or rabbit NBCeA.Figure D shows the slope conductances extracted from data for instance these for any larger quantity of cells.The switch from ND to mM HCO inside the presence of Li (i.e absence of Na) did not elicit a rise in membrane conductance (measured among mV and mV) in HOinjected cells (Fig.A).In reality, we measured a tiny but substantial reduce (P paired onetailed ttest).The same was true of cells expressing rabbit NBCeA (Fig.C; P paired onetailed ttest).Nonetheless, inside the six cells expressing human NBCeAEGFP (Fig.B), exactly the same maneuver elicited a little but considerable improve in slope conductance (P paired onetailed ttest).By comparing the HCOdependent slope conductances measured within the presence of Na vs.the presence of Li for these exact same six cells, we estimate that Li supports about with the electrogenic cationHCO cotransport activity supported by Na when the two cation species are present at a level of �� mM.As a result, human NBCeAEGFP exhibits detectable electrogenic LiHCO cotransport activity in oocytes.LiHCO cotransport by rabbit NBCeA is evidenced by a Liand HCOdependent hyperpolarization (see above), however the cotransport activity was not sufficiently robust to generate a measureable improve in membrane co.
