[Effects of both puerarin and gypsum on the firing of pyrogen-treated thermosensitive neurons in the region POAH of anesthetized cats].

To investigate the possible central mechanism of antipyretic effects of Chinese medicines, puerarin and gypsum, the firing rate of thermosensitive neurons in preoptic-anterior hypothalamus (POAH) region of 34 cats was recorded by using extracellular micro-electrode technigue. Injection of pyrogen caused decrease in firing rate of 14 warm-sensitive neurons and increase in firing rate of 11 cold-sensitive neurons in the region of POAH. The effects could be reversed by the injection of puerarin and gypsum. The results showed the antipyretic action of puerarin and gypsum might be mediated by influences on the electroactivity of pyrogen-treated thermosensitive neurons in the region of POAH. Effect of puerarin and gypsum on cold-sensitive neurons was stronger than that of single one, suggesting that both are synergic in central level.