ABSTRACT
<p><b>AIM</b>To investigate the possible central mechanism of antipyretic effects of Chinese medicine gypsum.</p><p><b>METHODS</b>Gypsum was injected after the fever model was established. The firing rate of thermosensitive neurons in preoptic-anterior hypothalamus(PO/AH) region was recorded by using extracellular microelectrode technique.</p><p><b>RESULTS</b>The injection of pyrogen evoked decrease in firing rate of the warm-sensitive neurons and increase in the cold-sensitive neurons in the region of PO/AH; the changes of the firing rate of pyrogen- treated warm-sensitive and cold-sensitive neurons could be reversed by the injection of gypsum.</p><p><b>CONCLUSION</b>The result may suggest that antipyretic action of gypsum is mediated by its influences on the thermosensitivity neurons in the region of PO/AH.</p>