Action potential mechanism of mammalian cortical neurons in cell culture.

Rat cortical neurons in 4- to 7-week-old dissociated cell cultures have action potentials (APs) which are tetrodotoxin-sensitive and appear to be generated by conventional sodium mechanisms. Approximately 10% of neurons can also generate APs when sodium channels are blocked. These latter APs are smaller, slower and sensitive to cobalt.

Biochemical correlates of GABA function in rat cortical neurons in culture.

Serial biochemical studies of a rat cortical tissue culture system in which synapses regularly form showed that gamma-aminobutyric acid (GABA) is present in the cultures and increases with their maturation. The tissue GABA concentration in mature cultures is similar to that of adult rat cortex in vivo. The synthetic enzyme, glutamate decarboxylase, also increases with age as does high affinity GABA uptake.

Electrical excitability of oat cell carcinoma.

Cultured tumour cells from two oat cell carcinomas of the lung were demonstrated to generate all-or-nothing, short-duration action potentials similar to those previously reported in neurones, in bronchial carcinoid cells, and in a number of endocrine cells of proven or proposed neural ancestry. This observation provides new evidence to establish oat cell carcinomas and carcinoids as closely related tumours distinct from other pulmonary neoplasms, and raises the possibility of treating these tumours by manipulation of hormonal agents.

Sodium and calcium action potential in pituitary cells.

Several endocrine cells or their neoplastic derivatives generate action potentials similar to those seen in neurones, and in the adrenal chromaffin cell such regenerative potentials depend primarily on a sodium mechanism. Kidokoro has described action potentials in the GH3 rat pituitary cell line which seem to depend on a calcium mechanism. We have re-investigated the action potential in GH3 cells and found that it results from combined Na and Ca mechanisms in physiological conditions.