Investigation of usefulness of electroreticulograms obtained from the sheep body surface in estimation of reticulum electrical activity.

The experiments were carried out on 3 sheep with one pair of platinum electrodes chronically implanted in the reticulum wall. The reticulum action potentials were recorded simultaneously from the body surface (using the needle electrodes placed subcutaneously) and from the implanted electrodes using an electroencephalograph Reega XVI Duplex TR. It was found that the two- or three-phase deflections on the electroreticulograms obtained from the body surface were exactly correlated with the series of potential spikes on the records from the implanted electrodes. The number of phases in each deflection was equal to the number of the series of potential spikes during the reticulum excitation. During the reticulum hypotony the decrease in action potentials was observed. That is why we were not able to record the electrical activity from the body surface, while it was still possible to record electroreticulograms from the implanted electrodes.

The phenomenon of reversal of reticulum action potentials recorded from the body surface of sheep.

The experiments were carried out on sheep with reticulum fistula. The biopotentials and transformed mechanogram of the reticulum were recorded simultaneously on the body surface with an electrocardiograph. Lactic acid solution 1.6 mol/l was administered through the fistula into the reticulum in an amount of 15 mmol/kg of body weight. It was found that administration of this acid caused reversal of the biopotentials of the reticulum. This phenomenon lasted from 10 to several scores of hours and occurred with pH of reticulum contents below the normal range as well as after return of normal pH.

The functions of bile ducts in sheep.

Pressure changes in the gallbladder and the bile flow and pressure changes in the common bile duct were determined in sheep. The experiments were conducted on animals with external junction of choleslochus and cholecystostomy performed previously. The experiments demonstrated pressure in the sheep of the functional sphincter of Mirizzi at the boundary between the intrahepatic and extrahepatic bile ducts. A correlation was demonstrated also between the function of this sphincter and that of Oddi's sphincter. The conditions for bile filling of the extrahepatic bile ducts and gallbladder were determined. The process of bile excretion into the duodenum and the role of bile duct sphincters in this process are discussed. Attention is called to the relationship between the pressure in the gallbladder and the tonus of bile duct sphinters.