Taurine transport in cultured choroid plexus.
OBJECTIVE
Taurine, a beta-amino acid, is a neuromodulator which interacts functionally with the glycinergic, GABAergic, cholinergic and adrenergic systems. Although a continuous cell culture model is not available for the choroid plexus epithelia, we recently described a primary cell culture of rabbit choroid plexus epithelia. The goal of the current study was to determine the suitability of this primary cell culture for the study of the Na(+)-taurine transporter in the rabbit choroid plexus.


METHODS
A primary cell culture of rabbit choroid plexus epithelial cells was grown on semi-permeable filters and kinetics of 3H-taurine uptake were ascertained.


RESULTS
Taurine transport in the cultured choroid plexus cell was Na(+)-dependent and saturable (Km = 156 microM). The beta-amino acids, beta-alanine and taurine, significantly inhibited Na(+)-driven taurine transport whereas L-alanine partially inhibited taurine transport in the cultured cells. In addition, we observed that the activity of the Na(+)-taurine transporter is affected by exposure to taurine in the media.


CONCLUSIONS
These results-demonstrate that a Na(+)-taurine transporter with characteristics similar to those in the intact tissue is expressed in cultured choroid plexus epithelial cells. The transporter may undergo adaptive regulation and play a role in taurine homeostasis in the central nervous system.
Ramanathan
V K
VK
Graduate Program in Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco 94143, USA.
Chung
S J
SJ
Giacomini
K M
KM
Brett
C M
CM
D000818:Animals; D001692:Biological Transport; D002478:Cells, Cultured; D002831:Choroid Plexus / Q000166:cytology / Q000378:metabolism*; D011817:Rabbits; D012964:Sodium / Q000378:metabolism; D013654:Taurine / Q000378:metabolism*
D013654:Taurine; D012964:Sodium