Ethanol reduces Ca2+ concentrations in arterial and venous smooth muscle.

The present results, using isolated rat aortic strips and portal vein segments, demonstrate that ethanol (170--430 mM) significantly inhibits calcium uptake in these 2 different types of vascular smooth muscle.     

Ethanol reduces Ca2+ concentrations in arterial and venous smooth muscle

Summary The present results, using isolated rat aortic strips and portal vein segments, demonstrate that ethanol (170–430 mM) significantly inhibits calcium uptake in these 2 different types of vascular smooth muscle.Supported by NIH grant No. HL-18015 and NIMH grant No. MH-26236. Request for reprints should be addressed to B.M. Altura.     

Differential effects of ethanol on prostaglandin responses of arterial and venous smooth muscles.

The present results, using isolated rat aortic strips and portal vein segments, demonstrate that ethanol, depending upon concentration, can either enhance or attenuate the contractile actions of PGF2alpha on at least 2 different types of vascular smooth muscle. At the very least, the present findings question that the use of ethanol as a solvent when investigating the contractile actions of PG molecules on smooth muscles.     

Eine Methode zur fortlaufenden Blutentnahme aus der Vena portae von Hunden

Summary A method is described for the introduction of a PVC.-Catheter into the portal vein of dogs. The catheter is introduced into one of the mesenteric veins of the ileum and pushed through the vena mesenterica communis until the portal vein is reached. The catheter, the end of which is fixed to the skin on the outside, can be removed without any injury to the animal by just drawing it out through the skin. The method can be applied for taking blood at various intervals during experiments on absorption, measurement of blood pressure in the portal vein and its branches, for the injection of substances directly into the liver, etc., on unanaesthetized animals.     

Besonderheiten im Feinbau des Endothels der Rattenpfortader

Summary After perfusion of the rat portal vein with the plasmaexpander Haemaccel, the morphological findings suggest an active transport of this material by means of cytopempsis. Moreover, the until now rarely described existence of microtubules in vascular endothelia could be confirmed. Their function might be that of a cytoskeleton.     

Differential effects of ethanol on prostaglandin responses of arterial and venous smooth muscle

Summary The present results, using isolated rat aortic strips and portal vein segments, demonstrate that ethanol, depending upon concentration, can either enhance or attenuate the contractile actions of PGF₂ on at least 2 different types of vascular smooth muscle. At the very least, the present findings question the use of ethanol as a solvent when investigating the contractile actions of PG molecules on smooth muscles.Supported by NIH grant No. HL-18015 and NIMH grant No. MH-26236. The authors are indebted to Dr.John E. Pike and Dr.John Babcock of the Upjohn Company for generously providing us with the PGF₂ used in this study.     

A simple method of obtaining multiple blood samples from the portal vein and the hepatic vein in the rat in vivo

A very simple and rapid technique for inserting a catheter in the portal vein and the hepatic vein in the anesthesized rat in vivo is described. The pointed, saline-containing PE tubing is frozen in liquid nitrogen, whereupon it is used as a 'needle' to insert the catheter into the blood vessel. Multiple blood samples can be obtained from the portal and the hepatic vein at the same time, so that in situ extraction of drugs by the liver can be measured in vivo, since hepatic blood flow is uninterrupted.     

Membrane potential in smooth muscle cells from hypertrophic rat portal vein

Cellular and Molecular Life Sciences - Portal hypertension was induced in rats by partial ligation of the hepatic branches of the portal vein. After 5 days the vein was removed and mounted in...     

Polyvinylchloride (PVC) particles implantation in mouse liver. A technique for experimental study of schistosome eggs-induced liver pathology.

An injection of suspended PVC particles in the caecal vein of mice induces a foreign-body portal granuloma reaction in the liver. Plastic casts of the portal system, after PVC particles implantation, show modifications in the portal bed and are compared with plastic casts obtained in mice infested by Schistosoma mansoni. This technique can be useful to study the cellular dynamics of the portal granuloma and can be a model for schistosomal eggs induced liver pathology.     

Smooth muscle in the hepatic artery, portal vein and hepatic vein within the liver of the raccoon and guinea pig

The amount and arrangement of smooth muscle in the intrahepatic vessels suggests that the guinea pig would be a good animal model for studying mechanisms controlling intrahepatic portal vein blood flow, while the raccoon would be good for studying hepatic vein mechanisms of control.     

Smooth muscle in the hepatic artery,portal vein and hepatic vein within the liver of the raccoon and guinea pig

Summary The amount and arrangement of smooth muscle in the intrahepatic vessels suggests that the guinea pig would be a good animal model for studying mechanisms controlling intrahepatic portal vein blood flow, while the raccoon would be good for studying hepatic vein mechanisms of control.     

The effect of urethane and pentobarbital anaesthesia and hepatic portal vein catheterization on liver blood flow in the rat

Summary The effect of urethane and pentobarbital anaesthesia and hepatic portal vein catheterization on liver blood flow was investigated in the rat. Liver blood flow with pentobarbital anaesthesia was 40% greater than with urethane. Hepatic portal vein catheterization had no effect under pentobarbital anaesthesia whereas it produced an 18% fall in liver blood flow with urethane.Acknowledgments. This work was supported by grants from ICI Pharmaceuticals and Mersey Regional Health Authority (Research Scheme No. 338). We wish to thank Mr P.J. Roberts for much skilled assistance and Evans Medical Ltd for the kind gift of drugs.     

Vascular reactivity in hypertension: Altered effect of ouabain

Summary Ouabain inhibits the relaxing effect of Ca²⁺ (but not of Mn²⁺) on contractile responses in tail artery strips isolated from spontaneously hypertensive and normotensive rats. The magnitude of ouabain inhibition was greater in vascular strips from hypertensive rats suggesting a significant difference in basic membrane function in hypertensive vascular smooth muscle.These studies were supported by National Heart, Lung, and Blood Institute grants HL-03765 and HL-18575-02-03. R.C. Webb is a Postdoctoral Research Fellow of the Michigan Heart Association.     

Polyvinylchloride (PVC) particles implantation in mouse liver. A technique for experimental study of schistosome eggs-induced liver pathology

Summary An injection of suspended PVC particles in the caecal vein of mice induces a foreign-body portal granuloma reaction in the liver. Plastic casts of the portal system, after PVC particles implantation, show modifications in the portal bed and are compared with plastic casts obtained in mice infested bySchistosoma mansoni. This technique can be useful to study the cellular dynamics of the portal granuloma and can be a model for schistosomal eggs induced liver pathology.This work was supported by an ATP (INSERM) 18.75.41 and a scholarship from the Société d'Hépatologie Expérimentale.     

Changes with hypertension and maturation in the response of stomach fundus to acetylcholine

The purpose of these experiments was to compare the contractile response to ACh of stomach fundal strips from hypertensive (SHR) and normotensive (WKY) rats during the development of hypertension. The results indicate that the reactivity to ACh is the same in fundal strips from young SHR and WKY rats; however, with maturation strips from WKY rats undergo a reduction in responsiveness which does not occur in the SHR. Therefore, strips from older SHR rats are more reactive to ACh than are those from age matched WKY rats.     

Effect of cholestasis and biliary diversion on the absorption of Na octanoate in the rat.

The intestinal absorption and portal vein transport of Na octanoate by isolated jejunal segments perfused in vivo were unchanged in rats studied 48 h after bile duct ligation or fistula.     

Hepatic glucose signals vagally modulate the cyclicity of gastric motility in rats

The cyclicity and intensity of gastric motlity were examined following glucose injection into the portal vein with an intragastric balloon in anesthetized rats. Enhanced gastric motility caused by insulin administration was influenced by 4 mM glucose (25 l) injected into the portal vein; glucose provoked a shift in the cyclicity power spectrum without any change in intensity. The peak power spectrum shifted from 4.0–5.0 cpm to 2.0–3.0 cpm. Hepatic branch vagotomy abolished the response.The results suggest that glucose signals in the hepatic vagal branch modulate the cyclicity of gastric motiligy.     

Changes in efferent activities of the gastric vagus nerve by administration of glucose in the portal vein.

Injection of glucose in the portal vein, as well as in the left carotid artery, brought a transient decrease in efferent discharges of the gastric vagus nerve, whereas venous injection of regular insulin brought a gradual increase in the discharges.     

Glycogenolytic effect of vasoactive intestinal peptide in the rat in vivo

Summary The effects of VIP (300 pmol/kg), injected via the portal vein, on the glycogen content of the liver and on glycemia, were studied in the rat in vivo. VIP enhanced glycogenolysis and caused hyperglycemia in a time-dependent manner.     

Effect of cholestasis and biliary diversion on the absorption of Na octanoate in the rat

Summary The intestinal absorption and portal vein transport of Na octanoate by isolate jejunal segments perfused in iivo were unchanged in rats studied 48 h after bile duct ligation or fistula.This work was supported by grant No. MT 4433 from the Medical Research Council of Canada.