Responses of Hepatic Microvessels

Abstract

The response of microvessels of the intact liver to various stimuli was observed in the anaesthetized rat by a modified transillumination tbchnique, permitting photomicrography at any time during the direct microscopic Rbservation. Adrenaline The hepatic circulation has been studied by many methods but the results were often controversial [Grayson and Mendel, 1965]. Therefore, it seemed worthwhile to examine further the responses of hepatic microvessels to various stimuli. This paper reports the results of such investigation with a modified method for direct microscopic observation of microcirculatory changes in the transilluminated liver. METHODSExperiments were carried out on 73 male Wistar strain albino rats, 100 to 150 g in body-weight, which were anaesthetized with sodium pentobarbitone (45 mg/kg intraperitoneally). The rat was placed in a supine position and kept warm by wrapping the body with cotton wool and by radiant heat of a nearby 100 W lamp. The external jugular vein and mesenteric vein were cannulated for intravenous and intraportal injections and the carotid arterial blood pressure was recorded routinely through a pressure transducer (Statham P23A). The abdomen was opened by a midline incision which was extended laterally to the left to expose the left lateral lobe of the liver. After severing the falciform and coronary ligaments of the liver, a diaphragmatic shield [Hanzon, 1952] was inserted between the liver and the diaphragm to eliminate movements of the liver due to respiratory excursions and heart beats. The anterior edge of the left lateral hepatic lobe was transilluminated as follows. The light from a 500-watt lamp of a projector (Argus Tru-Focus) was passed through a green filter (Hoya G (XI)) and the viewer of a Visoflex (Leitz) and reflected by a mirror in the latter to a microscope condenser (Watsons, service type). Then a round tapered perspex rod 11-4 cm long with the wide end of the rod attached to the condenser transmitted the light to its opposite narrow end, diameter 4 mm, which was cut at

The Effect of Noradrenaline and Adrenaline on Hepatosplanchnic Hemodynamics, Functional Capacity of the Liver and Hepatic Metabolism

“…This may indicate functional differences between the vasculature in intact and isolated liver. In transillumination studies on rat livers noradrenaline and adrenaline caused sinusoidal constriction (Seneviratne 1950, Ho 1972) and redistribution of the intrahepatic blood flow (Wakim 1944). This was to some extent confirmed in a radioangiographic study in cats (Daniel and Prichard 1951 ) .…”

“…Transillumination studies have revealed that catecholamines may change the intrahepatic distribution of blood flow, causing a decrease in the number of perfused sinusoids (Wakim 1944, Seneviratne 1950, McCuskey 1966, Ho 1972. Th' is concept has to some extent been supported by Daniel and Prichard (1951) in a radioangiographic study.…”