Fig. 2.

Postsynaptic Na⁺-K⁺-ATPase pump activity mediates post-PTH. A: postsynaptic APs evoked by afferent fiber stimulation (100 Hz, 3-s duration) in control (black) and in the presence of ouabain (100 μM, gray; a blocker of Na⁺/K⁺-ATPase) in a P16 rat MNTB principle neuron. B: expanded voltage scale for the same post-PTH shown in A. Horizontal lines indicate the resting membrane potential. Ouabain depolarized the postsynaptic neuron from −70 to −55 mV. Note that the postsynaptic neuron showed a progressive hyperpolarization during the AP train (control), which was blocked by ouabain. Note also that application of ouabain increased the number of spontaneous postsynaptic potentials after the AP train (gray arrowheads). Black arrowheads indicate the post-PTH.