Rapid determination of cellular metabolic rates with a silicon microphysiometer

The microphysiometer is a silicon-sensor based instrument designed to measure the metabolic rates of small numbers of living cells. By improving the electronic noise level of this instrument, the authors have increased the temporal resolution of metabolic rate measurement by about an order of magnitude compared to previous versions of the instrument. This enables the study of relatively fast cellular responses to receptor/ligand binding. Results obtained with a cell line (TE671) that is known to contain acetylcholine receptors are presented. The kinetics of the cellular response to an acetylcholine agonist is shown to be complex, with three distinct resolvable phases. Through pharmacological manipulations it is demonstrated that the response is due to a muscarinic acetylcholine receptor.<>