Electrophysiological evidence for the reconstitution of chemosensory units in co-cultures of carotid body and nodose ganglion neurons.

The electrophysiological characteristics of nodose ganglion sensory neurons, cultured alone or co-cultured with carotid body tissue, were compared. Some properties of the neurons and their response to acid (a carotid body 'natural' stimulus) changed in the presence of this tissue. (a) The evoked action potential after-hyperpolarization was smaller and longer whereas spike amplitude and duration, and the passive membrane properties remained unaltered. (b) Spontaneously occurring action potentials happened more frequently (16% vs 3%). (c) Acid solutions induced appreciable depolarization, an increased discharge, or both, only in a population of co-cultured neurons. These changes probably arose because of synaptic and/or trophic interactions between neurons and glomus cells.