Taurine-induced long-lasting potentiation in the rat hippocampus shows a partial dissociation from total hippocampal taurine content and independence from activation of known taurine transporters.
Perfusion with high millimolar levels of taurine evoked a long-lasting potentiation (LLP-TAU) of synaptic transmission in the Schaffer-collateral CA1 region of the rat hippocampus. Although LLP-TAU showed some correlations to increases in the total taurine content of hippocampal slices, it could not be blocked by the taurine transport inhibitor guanidinoethanesulfonic acid (GES), which was able to significantly reduce total slice taurine uptake. Inhibition of GABA transport by either nipecotic acid or beta-guanidinopropionate failed to abolish LLP-TAU and had no significant effect on taurine uptake. The combination of GES and nipecotic acid also had no significant effect on LLP-TAU. Experiments with transportable structural analogs of taurine (beta-aminoisobutyric acid, homotaurine, and isethionic acid) suggest that activation of classical taurine transport pathways does not always yield a robust LLP-TAU. Hippocampal LLP-TAU could be significantly attenuated, however, by pre-incubation with submillimolar levels of taurine. In summary, the development of LLP-TAU in the rat hippocampus appears to be associated with the intracellular accumulation rather than the activation of known transporters of taurine, but the precise means of its accumulation remains to be identified.
Dominy
John
J
Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, FL 32610, USA.
Thinschmidt
Jeffrey S
JS
Peris
Joanna
J
Dawson
Ralph
R
Papke
Roger L
RL
D000818:Animals; D002352:Carrier Proteins / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D006146:Guanidines / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000378:metabolism*; D026901:Membrane Transport Proteins; D009557:Nipecotic Acids / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013654:Taurine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D000099247:Taurine Transporters
D002352:Carrier Proteins; D006146:Guanidines; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009557:Nipecotic Acids; D011422:Propionates; D013654:Taurine; D000099247:Taurine Transporters; C030278:nipecotic acid; C009558:taurocyamine; C005775:guanidinopropionic acid