Dynamic determination and possible mechanism of amino acid transmitter release from rat spinal dorsal horn induced by the venom and a neurotoxin (BmK I) of scorpion Buthus martensi Karsch.

In the present communication, we determined the dynamic release of amino acid transmitters from spinal dorsal horn induced by scorpion Buthus martensi Karsch (BmK) venom and a neurotoxin (BmK I). The results found that glutamate and aspartate release could be evoked significantly within the initial 30 min with the applied doses of either 0.05 and 0.01 mg BmK venom or 0.01 and 0.002 mg BmK I. However, gamma-aminobutyric acid (GABA) release could be largely evoked during the second 30 min by the venom, but not by BmK I. The result suggested that nociceptive afferent fibers could be activated to induce excitatory amino acid release from spinal dorsal horn by nociceptive factors such as BmK I, but the delayed release of GABA might be attributed to the modulating role of some antinociceptive components in the venom. Copyright 2002 Elsevier Science Inc.