Central temperature effects of the transmitter amino acids

Experiments were carried out to determine the temperature changes induced by the transmitter amino acids gamma-aminobutyric acid (GABA), taurine and glycine (representatives of the inhibitor class of amino acids), and of L-glutamic acid and L-aspartic acid (representatives of the excitatory functional class of amino acids). The amino acids were introduced directly into the preoptic anterial part of the hypothalamus (PO/AH). The experiments were made on male Wistar rats into which cannules were implanted in advance in PO/AH using a stereotaxic apparatus and coordinates of administration after König and Klippel. At ambient temperature of 22 degrees C GABA and taurine are found to cause a dose-dependent hypothermal response, L-aspartic acid and L-glutamic acid lead to dose-dependent hyperthermia, while glycine does not change the body temperature.