Techniques in tissue metabolism. 2. Application of electrical impulses to separated tissues in aqueous media

Abstract

An instrument is descr. which works from A. C. mains and produces alternating condenser pulses suitable for applying to separated tissues, and with measurement and control of potential and duration. Electrodes and vessels are descr. which can be used with the Warburg apparatus. The potentials established in neutral saline solns. between such electrodes showed an approx. uniform potential gradient to within 1.2 mm. of silver wire electrodes. An abrupt potential change occurred between metal and soln. This increased with increasing voltage and with cycles above 2000/sec, was much larger for Mo and steel than Ag or Au thus decreasing the potential gradient in soln. Grid electrodes and concentric electrodes gave similar but more complex potential distance relationships. Stimulated guinea-pig cerebral cortex (chopped suspension or tissue slices) showed increased respiration over controls. No significant difference was found in the percent increase with different electrodes but respiration increased with voltage, being 200% of normal at 24 volts. Simple concentric electrodes attached to a glass rod in a test-tube containing guinea-pig cerebral cortex fragments in glucose-phosphate-saline-Ca were adequate to double the lactic acid production with condenser discharges of 20 volts, 0.3-0.45 msec and with 50 cycle a.c. at 3 volts, 18 mA.