Fig. 6.

Effects of quinpirole on the voltage-dependent modulation of the rate of rise of the LTS. When the first derivative of the LTS amplitude was plotted against the membrane potential, the data between −65 and −85 mV could be fit to a sigmoidal function. Furthermore, quinpirole appeared to facilitate the LTS for membrane potential values between −65 and −70 mV. However, for values of membrane potential between −56 and −65 mV, quinpirole caused a substantially larger facilitation of LTSs but could not be fitted to a sigmoidal function. Every point represents the average of seven cells collected during control conditions (•) and after quinpirole administration (○).