EFFECTS OF GENERAL-ANESTHETICS ON CULTURED LYMNAEA NEURONS

In order to elucidate the mode of action of general anaesthetics we ar e using neurones of Lymnaea stagnalis as a model system. Neurones exhi bit mainly two types of responses to anaesthetics delivered at clinica l concentrations, i.e. , either gradually going into quiescence or exh ibiting paroxysmal depolarizing shifts (POS). In order to determine wh ether these differences are due to intrinsic membrane properties or be cause of synaptic effects, cultured neurones are being used so that ce lls can be studied in isolation from any synaptic effects. Cells in cu lture retain their basic electrophysiological characteristics and beha ve in a similar manner to the applied anaesthetics as do whole brain p reparations. Demonstration of POS 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 consi stent with the suggestion that anaesthetics may influence the inward c alcium current or other calcium-dependent currents.