We examined molecular and electrophysiological properties of the electroneutral sodium/bicarbonate cotransporter (NBCn1) that is present in rat hippocampal neurons. By PCR, a deletion variant (NBCn1-E) that lacks 123 amino acids in the cytoplasmic N-terminal domain was found in adult neurons. The previously characterized NBCn1-B, which does not have the deletion, was detected in embryonic neurons. In Xenopus oocytes, NBCn1-E raised the intracellular pH in the presence of HCO 3 without significantly affecting the membrane potential. Despite this electroneutral cotransport activity, the transporter mediated a steady-state current that positively shifted the resting potential by almost 30 mV. The mean reversal potential of the steady-state current was ؊21.2 mV, close to the resting potential of ؊21.4 mV. The reversal potential shifted 26 mV in response to a 10-fold increase of external Na ؉ for concentrations above 10 mM. The current activity mediated by the transporter was unaffected by K ؉ , Mg 2؉ , Ca 2؉ , or Cl ؊ . Stable expression of NBCn1-E in human embryonic kidney cells also evoked an inward current that shifted the resting potentials more positive compared with the sham-transfected controls. In primary cultures of embryonic hippocampal neurons, the NBCn1 protein was localized in somatodendrites and synapses. NBCn1 protein was partially colocalized with the postsynaptic density protein PSD-95. Single-cell PCR showed that NBCn1 mRNA expression was present in both ␥-aminobutyric acid (GABA)ergic and non-GABAergic neurons. We propose that NBCn1 in hippocampal neurons may affect neuronal activity by regulating local pH as well as steady-state inward currents at synapses.

Bear bile has been included in Asian pharmacopeias for thousands of years in treatment of several diseases, ranging from sore throat to hemorrhoids. The hydrophilic bile acids tauroursodeoxycholic acid (TUDCA) and ursodeoxycholic acid (UDCA) are the major bile acids of bear bile. Both of these are available as synthetic formulations and are approved by the health administrations of several countries for treatment of cirrhosis and gallstones. This review briefly covers the use of bear bile in Traditional Chinese Medicine, bile acid physiology, approved use of UDCA and TUDCA in Western medicine, and recent research exploring their neuroprotective properties, including in models of ocular disease.

The rapid differential decrease in HA levels during negative lens compensation and the absence of any difference after just 1 day of recovery suggest that HA levels may play a previously unrecognized early role in regulating the biomechanical property (creep rate) of the sclera. The reduced levels of the other GAGs, which occur when creep rate is at its peak elevation, and their rapid return to normal after 1 day of recovery suggest that they may also participate in regulating this biomechanical property of the sclera.