Effects of general anaesthetics on cultured Lymnaea neurones.

In order to elucidate the mode of action of general anaesthetics we are using neurones of Lymnaea stagnalis as a model system. Neurones exhibit mainly two types of responses to anaesthetics delivered at clinical concentrations, i.e., either gradually going into quiescence or exhibiting paroxysmal depolarizing shifts (PDS). In order to determine whether these differences are due to intrinsic membrane properties or because of synaptic effects, cultured neurones are being used so that cells can be studied in isolation from any synaptic effects. Cells in culture retain their basic electrophysiological characteristics and behave in a similar manner to the applied anaesthetics as do whole brain preparations. Demonstration of PDS and quiescence in cultured neurones shows that these phenomena are due to membrane effects and not due to synaptic inputs. The effects of anaesthetics observed seem to be consistent with the suggestion that anaesthetics may influence the inward calcium current or other calcium-dependent currents.