Development of neuronal excitability of the bushy cells in anteroventral cochlear nucleus of rats

The ultrafast and precise single-onset action potential (AP) of the bushy cells (BCs) in the anteroventral cochlear nucleus (AVCN) plays an essential role in the precise processing of temporal auditory information for localizing sound sources and communication cues. The specialized properties of high conductance of low-voltage-activated potassium channel (K+LVA) contribute to generate ultrafast and precise single-onset APs in BCs. However, the developmental changes of K+LVA distribution and their contributions to shape neuronal excitability of BCs remain unclear. Therefore, we investigated the developmental changes in neuronal excitability of BCs and K+LVA distribution at different developmental periods. Using electrophysiological recording, we first characterized the firing pattern of BCs in response to a sequence of current injections at different developmental periods. The expression of K+LVA subunit Kv1.1 in AVCN was examined with western blot. The results indicated that BCs showed single-onset AP firing patterns and paused multiple APs firing patterns at the postnatal time of day 7 (P7) and were then refined into single-onset firing pattern at P14 and P21. With development, the active membrane properties, including latency and half-width of AP, and passive membrane properties, including capacitance, input resistance, and time constant, were significantly decreased. Furthermore, the refinement of firing patterns in BCs was correlated with the upregulation of the Kv1.1 cha...
Source: Developmental Neuroscience - Category: Neuroscience Source Type: research