What Are Electrophysiology Chambers?
Electrophysiology chambers are designed to study tissue electrophysiology in preclinical research. These chambers can be used for tissue slices in neuropharmacological and toxicological animal models in preclinical research, especially in rodents like rats and guinea pigs.
Electrophysiological recordings can be taken simultaneously from tissue slices using electrophysiology chambers, which allows researchers to examine multiple tissues simultaneously. Electrophysiology chambers are used in the electrophysiological evaluation by recording action potentials, measuring extracellular field potentials, and determining excitation with multielectrode arrays (MEA) in multiple preparations synchronically. 
The thickness of tissue slices and the protocol used in electrophysiology chambers can be varied to record type. Tissue slices can be prepared appropriately so that they can be examined electrophysiologically.
For example, in a study using electrophysiology chambers, researchers make 350 μm-thick slices to record extracellular field and intracellular action potentials. In another study using electrophysiology chambers, scientists prepare 300 µm-thick transmural longitudinal, transverse, and sagittal slices to measure extracellular potentials.
Although the multielectrode array (MEA) technique of brain tissue slices is common, fewer studies have been conducted on the heart because of the slicing complexity of heart tissue.
For preclinical research, recording applications include a multielectrode array, which is essential to determine how the heart works. It allows easy recording from the tissues. These tissue slices are assembled into a four-channel electrophysiology chamber.
On the other hand, understanding the effects of new chemicals like drugs on action potential is possible by using tissue slices of the heart. Although the use of cardiac slices to study the effects of chemicals on action potential parameters is relatively new, these slices can be used for a couple of days and help increase our knowledge about early cardiovascular assessment.
Electrophysiology Chambers Examples in Rodent Research
Scientists from Germany investigated the drug effects with ventricular heart slices in male guinea pigs and Wistar rats. Their investigation of extracellular field potential was possible by fixing slices in a chamber with oxygenated Tyrode’s solution (2 ml/min) at 34 °C.
The equilibration process is over after 30 min, followed by the field potential recording. Field potential was ensured by 400 μs of single biphasic electric pulses of convenient amplitude (100 to 800 μA, peak-to-peak) at a repetition rate of 1/s. Afterwards slices were mounted in a bath and superfused, then stimulated with a concentric bipolar stimulation electrode. Researchers found that heart tissue slices are a powerful tool for electrophysiological research.
Heart tissue slices are commonly used to investigate adult rats and guinea pigs in various preclinical research. To investigate different rodents in the electrophysiological research setting, a concentrical bipolar electrode can be centrally placed to execute biphasic stimulation pulses (200-300 µs duration).
Thus, extracellular potentials of tissue slices can be recorded. In another setting, heart slices of adult rats and guinea pigs can be placed in multielectrode arrays with 200 µm interelectrode distance and 30 µm electrode diameter. Therefore, extracellular field potentials and their propagation throughout the heart slice can be recorded with multielectrode arrays-60.
As in the research listed using electrophysiology chambers, electrophysiology chambers are vital equipment to assess the effects of tissue slices in preclinical research in laboratory settings. These chambers provide crucial output for preclinical research’s pharmacological and physiological investigations.
- Pugsley, M. K., …, & Curtis, M. J. (2011). Innovation in safety pharmacology testing, Journal of Pharmacological and Toxicological Methods, 64.
- Bussek, A., …, & Lohmann, H. (2012). Cardiac tissue slices with prolonged survival for in vitro drug safety screening, Journal of Pharmacological and Toxicological Methods, 66(2).
- Lohmann, H., …, & Ravens, U. (2006). Isolated living heart slices from adult rats and guinea pigs as a model for drug testing. Naunyn-Schmiedebergs Archiv for Pharmacology, 372(332).
- Pugsley, M. K., & Curtis, M. J. (2012). Methodological innovations expand the safety pharmacology horizon, Journal of Pharmacological and Toxicological Methods, 66(2).
- Lohmann, H., …, & Ravens, U. (2006). MEA recordings from acute heart slices from adult rats and guinea pigs. Poster Presentation.