Hyperpolarization-activated currents regulate excitability in stellate cells of the mammalian ventral cochlear nucleus.

The differing biophysical properties of neurons the axons of which form the different pathways from the ventral cochlear nucleus (VCN) determine what acoustic information they can convey. T stellate cells, excitatory neurons the axons of which project locally and to the inferior colliculus, and D stellate cells, inhibitory neurons the axons of which project to the ipsi- and contralateral cochlear nuclei, fire tonically when they are depolarized, and, unlike other cell types in the VCN, their firing rates are sensitive to small changes in resting currents. In both types of neurons, the hyperpolarization-activated current (I(h)) reversed at -40 mV, was activated at voltages negative to -60 mV, and half-activated at approximately -88 mV; maximum hyperpolarization-activated conductances (g(h max)) were 19.

Tityustoxin-K(alpha) blockade of the voltage-gated potassium channel Kv1.3.

1. We investigated the action of TsTX-Kalpha on cloned Kv1.3 channels of the Shaker subfamily of voltage-gated potassium channels, using the voltage-clamp technique.