In 19 cats anesthetized with α-chloralose effects of taurine and β-alanine on the responses of wide dynamic range (WDR) cells to mechanical, chemical and thermal stimuli were investigated in the lumbar spinal cord of the cat. Also studied was an interaction of strychnine with taurine in affecting the activities of WDR cells. Following intravenous administration of taurine, the responses of WDR cells to all types of mechanical stimuli were markedly enhanced, demonstrating that the response to pressure was most sensitive to taurine action. When the receptive field was exposed to thermal stimuli (50℃) for 20 sec. taurine increased activity of WDR cell to 169.5% of the control value. The K⁺-induced activation of WDR cells was invariably suppressed after taurine administration. Intravenously administered strychnine remarkably reduced the enhanced response of WDR cell to natural stimuli resulting from intravenous administration of taurine. Also β-alanine markedly activated the response of spinal dorsal horn cell to natural mechanical stimuli. These findings suggest that neutral amino acid and its derivative such as β-alanine and taurine can enhance the response of WDR cells to different stimuli in cats.