Amino acids in the dorsal lateral geniculate nucleus of the cat--collection in vivo.

A dialysis sampling probe was used to collect amino acids from the dorsal lateral geniculate nucleus (LGN) in vivo. The sampling probe was equipped with an electrode to allow local stimulation and recording of nerve activity. The amino acids in the dialysates were determined fluorimetrically by precolumn derivation and hplc-separation. Local electrical stimulation of the LGN caused a multifold increase in glutamate, aspartate and GABA levels. Smaller changes were observed for taurine, alanine and glycine. The results indicate that the dialysis sampling probe is rather atraumatic and can be used to detect stimulation-induced changes in extracellular amino acid concentrations.