Comparison of the effects of hepatic nerve stimulation on arterial flow, distribution of arterial and portal flows and blood content in the livers of anaesthetized cats and dogs

Abstract

SUMMARY1. The responses to hepatic nerve stimulation were studied in cats and dogs anaesthetized with sodium pentobarbitone. In three series of experiments, hepatic arterial flow was recorded by an electromagnetic flowmeter, intrahepatic distributions of arterial and portal flows were studied by radioactive microspheres, and hepatic volume responses were measured by a plethysmographic method.2. In cats, nerve stimulation produced a frequency-dependent decrease in hepatic arterial flow which was not maintained and autoregulatory escape occurred. In dogs, the initial decrease in arterial flow was similar but escape did not occur and the vasoconstriction was well maintained.3. In both cats and dogs, stimulation of the hepatic nerves did not cause a redistribution of either arterial or portal flows within the liver. Autoregulatory escape in the liver of the cat was not associated with an intrahepatic redistribution of arterial flow and is best interpreted as relaxation of the same vessels which were initially constricted, due to increased production of a vasodilator factor.4. Stimulation of the hepatic nerves caused a marked frequencydependent decrease in hepatic volume which was well maintained and the responses were similar in cats and dogs. The quantitative importance of the liver as a blood reservoir is compared in relation to other vascular beds and the concept of the blood volume reserve is discussed.

Blood mobilization by regional vascular beds during cerebral ischemic pressor response in rabbits.

“…This trend faded away as SAP rose further with more severe cerebral ischemia. In the present study, an average blood volume of 8.4 ml/100 g of tissue was mobilized from the liver by maximum cerebral ischemic pressor response in a normovolemic state, but this value was slightly lower than the results obtained in dogs by hepatic nerve stimulation (GREENWAY and OSHIRO, 1972). Slight expansion of the skeletal muscle vascular volume during the initial pressor response with a modest reduction of cerebral blood flow regardless of the volemic status in animals may be attributed to the following.…”

The effect of a pre‐operative infusion of Ringer's solution on splanchnic perfusion in patients undergoing coronary artery bypass grafting

“…Girbes et al [20] reported improved postoperative healing in high-risk patients who had pre-operative volume replacement. Greenwas et al [21] showed that volume replacement increases liver perfusion through both a decrease in hepatic vascular resistance and an increase in cardiac output. In our study, baseline cardiac output was similar in the two groups, while indocyanine green clearance was higher in the crystalloid group.…”

Farmacocinética do propofol em nanoemulsão em gatos

“…O fl uxo sanguíneo hepático em gatos é citado como em torno de 21mL kg -1 min -1 (GREENWAY & OSHIRO, 1972), assim, os valores de clearance do propofol encontrados estão iguais ou abaixo destes, o que pode indicar baixa extração hepática do fármaco. BESTER (2009), supôs que, devido a esta extração defi ciente, o débito cardíaco pouco infl uenciaria na depuração do propofol em felinos, pois a variação do fl uxo não seria signifi cativa.…”