There are many transmitter substances which regulate the activity of nerve cells of the central nervous system. The objective of this proposal is to elucidate the mechanisms by which these transmitter substances activate intracellular messenger processes that lead to the modulation of excitability through their action on potassium channel conductance properties. Recent studies have shown that excitability of neurons is dependent on potassium channels which are, in turn, regulated by G-proteins called Gi and Go, of which there are several subtypes. The specific aim of this investigation is to identify which of the G-protein subtypes are related to neurotransmitter action (acetylcholine and somatostatin). Molecular biological techniques will be used to produce specific mutations to selectively inactivate G-proteins and thereby determine which of them is directly affected by the neurotransmitters to act on potassium conductance of the cell. For this purpose mutated alpha subunits will be inserted into AtT-20 cells, a pituitary tumor cell line which contain G-protein regulated potassium channels. The effect of the mutants can then be ascertained on potassium channel function.
