Intrahepatic distribution of nerves in the rat

Abstract

The intrahepatic distribution of nerves in the rat was studied using neurohistochemical and electron microscopic methods. Innervation was restricted primarily to vessels in the portal space and hilus. Both adrenergic and cholinergic fibers were observed in the adventitia of hepatic arteries, and to a lesser extent adjacent to portal veins. Some of the cholinergic fibers, however, were not contiguous with the vasculature. Near the hilus many of these fibers were associated with ganglia while peripherally some coursed into the immediately adjacent parenchyma where end bulbs abutted on hepatocytes. Ultrastructurally, scattered small nerves, devoid of neurolemma, were found contiguous with the portal lamina of hepatocytes. Nerve fibers deeper within the lobule were not seen but numerous gap junctions were observed between contiguous hepatocytes. Central and sublobular hepatic veins lacked innervation but adrenergic nerves were demonstrated in the walls of larger hepatic veins. Innervation of the biliary system was sparse. While nerves were interposed between vessels and bile ducts, such nerves tended to be associated more closely with the vasculature.

Hepatic Branch Vagotomy Can Suppress Liver Regeneration in Partially Hepatectomized Rats

“…The relative liver weight showed a similar pattern of change in the hepatic vagotomized rats and the controls, but comparison of the relative liver weight 7 days after surgery between the groups showed a significant difference in the value and the weight was lower in the vagotomized rats than in the controls (p<0.05, n=6). However, this difference disappeared 14 Changes in food and water intakes in the hepatic branch vagotomized and the control groups were also examined ( Figure 3). The total water intake (Mean + SEM) during the first 7 days after the denervation was 142.7 + 9.8 (n 6) ml in the controls, while it was 154.3 + 16.9 (n 6) ml in the vagotomized rats, indicating no significant difference between the two values.…”

Electron microscope study on the innervation of guinea pig liver - proposal of sensory nerve terminals in the hepatic parenchyme.

“…The previous studies have revealed, many unmyelinated nerves running in the portal tract along the interlobular arteries, veins and biliary ductules (portal triads) (SUTHERLAND, 1964;UNGVARY and DONATH, 1969;ANUFRIEW et al, 1973;SKAARING and BIERRING, 1976;FORSSMANN and ITO, 1977;REILLY et al, 1978;MCCUSKEY, Fig. 16.…”

“…Since the light microscopic study on the Innervation of mammalian liver carried out by RIEGLE (1928) with the silver impregnation method, many investigations have been carried out to elucidate the nature of nerves supplying the liver with a variety of methods: not only electron microscopy but also histochemistry for cholinesterase, fluorescence method, autoradiography using 3H-noradrenalin, and chemical denervation of sympathetic nerves with 6-OH-dopamine (SUTHERLAND, 1964;UNGVARY and DONATH, 1969;ANUFRIEW et al, 1973;SATLER et al, 1974;SKAARING and BIERRING, 1976;FORSSMANN and ITO, 1977;UNO, 1977;REILLY et al, 1978;NOBIN et al, 1978;MCCUSKEY et al, 1979;SAWCHENKO and FRIEDMAN, 1979). YAMADA (1965), ITO and SHIBASAKI (1968) and TSUNEKI and ICHIHARA (1981) utilized transmission electron microscopy (TEM) to study the innervation of the liver in man, the monkey, mouse, several other mammals, birds and lower vertebrates.…”

“…The cholinergic nerve fibers distributed in the hepatic tissue are thought to be derived from the postganglionic fibers of parasympathetic neurons located near the hepatic porta and in the portal space (tract) (SUTHERLAND, 1964;REILLY et al, 1978). The adrenergic fibers supplying the hepatic tissue are believed to be postganglionic fibers of the celiac ganglion (MCCUSKEY et al, 1979).…”

“…The sum of the transmitter substances to be released into the Disse's space, as well as into the portal space, can be presumed to be a considerable amount. As for the synaptic connections between hepatocytes and the autonomic vesiculate terminals, many authors, including YAMADA (1965) and ITO and SHIBASAKI (1968), have reported them in various vertebrates (FORSSMANN and ITO, 1977;UNO, 1977;NOBIN et al, 1978;REILLY et al, 1978;TSUNEKI and ICHIHARA, 1981 etc.). SATLER et al (1974), however, could not reveal any direct connections between nerve terminals and hepatocytes in the rat, thus assuming only diffusion innervation to hepatocytes (synapse per distance).…”