The PRESENCE OF Β‐ADRENERGIC RECEPTORS IN THE HEPATIC VASCULATURE

Geumei, Aida; Mahfouz, Mahmoud

doi:10.1111/j.1476-5381.1968.tb00447.x

Cited by 20 publications

(14 citation statements)

References 14 publications

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“…The control mean hepatic arterial flow in the propranolol-pretreated dog was lower than in the normal dog. This would indicate that an increased state of vasoconstriction existed after pro pranolol confirming previous observation (13,14).…”

Section: Discussionsupporting

confidence: 91%

Prostaglandin E<sub>1</sub>: Its Effects on Hepatic Circulation in Dogs

et al. 1973

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The effects of intravenous, intra-arterial and intra-portal administration of prostaglandin E₁ (PGE₁) on hepatic artery (HA) and portal vein (PV) flows were studied in anaestetized dogs. Intravenous administration of PGE₁ (1 µg/kg) produced an increase in HA flow, PV flow and PV pressure concomitant with a significant decrease in systemic arterial pressure, whereas, the injection of the same dose of PGE₁ into the portal vein caused essentially no change in PV flow, PV pressure, or systemic arterial pressure. Intra-arterial injection of PGE₁ increased HA flow and decreased its resistance, with no change in systemic arterial pressure. The hepatic arterial effect of PGE₁ was dose-dependent and was not abolished after β-adrenoceρtor blockade by propranolol 1 mg/kg i.v. It is concluded that PGE, possesses a direct dilator action on HA and indirectly influences the portal venous circulation.

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Section: Discussionsupporting

confidence: 91%

Prostaglandin E<sub>1</sub>: Its Effects on Hepatic Circulation in Dogs

et al. 1973

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“…Its rate of elimination in normal individuals is highly dependent on HBF, consequently ICG has been used to estimate HBF (Weigand, Ketterer & Rapaport, 1960;Caesar, Shaldon, Chiandussi, Guevara & Sherlock, 1961) Physiological variables expected to affect HBF, exercise, posture and milk ingestion, were chosen for study. In addition the effect of adrenoceptor blockers on HBF was examined in view of the reported effects of /8-adrenoceptor blockade on drug clearance and presence of adrenoceptors in splanchnic vessels (Guemei & Mahfouz, 1968;Hanson, 1972 …”

Section: Introductionmentioning

confidence: 99%

Physiological and pharmacological variability in estimated hepatic blood flow in man.

Daneshmend¹,

Jackson²,

Roberts³

1981

Brit J Clinical Pharma

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1 Changes in hepatic blood flow have been estimated by measurement of single-dose indocyanine green kinetics in groups of healthy individuals. 2 The effects of change in posture, exercise and ingestion of milk on estimated hepatic blood flow have been assessed. 3 The erect posture and exercise significantly decreased ICG clearance. However, no consistent change was noted after ingestion of milk. 4 The effects of the adrenoceptor blocking drugs phenoxybenzamine, propranolol and labetalol on hepatic blood flow were also assessed. 5 Propanolol and labetalol caused a significant fall in ICG clearance in the supine position. Phenoxybenzamine did not show a consistent change. 6 Posture, exercise and adrenoceptor blockade appear to be important variables affecting hepatic blood flow. They should be considered when kinetics of high-clearance drugs are measured, and may provide a useful model for the assessment of the effects of alterations in hepatic blood flow on the clearance of drugs.

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“…Studies of the effect of catecholamines on the hepatic circulation in various species of experimental animals provided evidence for the presence in the liver vascular bed of alpha-adrenergic receptors [Green, Hall, Sexton and Deal, 1959;Bender and Horvath, 1965;Nardi, 1966;Greenway, Lawson and Mellander, 1967] and beta-receptors [Scholtholt, Lochner, Renn and Shiraishi, 1967;Geumei and Mahfouz, 1968;Greenway and Lawson, 1969;Ross and Kurrasch, 1969;Fischer, Takacs, Bencsath and Vaslaki, 1970]. We have recently demonstrated the presence in the hepatic sinusoids of the rat of both alpha-and beta-receptors which could provide antagonistic constrictor-dilator components in the sinusoids.…”

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Adrenergic Mechanisms in the Hepatic Microcirculation in the Rat

1977

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The in vivo hepatic microvascular bed of the rat was observed microscopically in the transilluminated liver and the diameter of the hepatic sinusoids was measured by serial photomicrography. Intraportal infusion of tyramine induced concentration-dependent constriction of the hepatic sinusoids, but also dilatation of the sinusoids when the dose was small. These effects were attributed to the release of endogenous noradrenaline which activated either alpha-or beta-adrenergic receptors and caused constriction, or dilatation, of the sinusoids respectively. Adrenaline and noradrenaline induced similar changes in the hepatic sinusoids as tyramine, while phenoxybenzamine induced dilatation, and propranolol constriction, of the sinusoids. All the above responses were abolished by pretreatment with reserpine. A possible noradrenaline-mediated basal vasomotor tone in the hepatic sinusoids for autonomic control of the blood flow in the sinusoids was postulated.The regulation of hepatic blood flow is still unsettled [Greenway and Stark, 1971], while the regulation of blood flow in the hepatic sinusoids is even more obscure. Studies of the effect of catecholamines on the hepatic circulation in various species of experimental animals provided evidence for the presence in the liver vascular bed of alpha-adrenergic receptors [Green, Hall, Sexton and Deal, 1959;Bender and Horvath, 1965;Nardi, 1966;Greenway, Lawson and Mellander, 1967] and beta-receptors [Scholtholt, Lochner, Renn and Shiraishi, 1967;Geumei and Mahfouz, 1968;Greenway and Lawson, 1969;Ross and Kurrasch, 1969;Fischer, Takacs, Bencsath and Vaslaki, 1970]. We have recently demonstrated the presence in the hepatic sinusoids of the rat of both alpha-and beta-receptors which could provide antagonistic constrictor-dilator components in the sinusoids.The purpose of the present study is, therefore, to determine whether the above receptors respond to the released endogenous neuro-transmitter noradrenaline, and to elucidate the role of such adrenergic constrictor-dilator mechanism in the hepatic sinusoids in the control of blood flow in the terminal hepatic microcirculation. Some of the findings have been reported in an abstract . METHODS

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The PRESENCE OF Β‐ADRENERGIC RECEPTORS IN THE HEPATIC VASCULATURE

Cited by 20 publications

References 14 publications

Prostaglandin E<sub>1</sub>: Its Effects on Hepatic Circulation in Dogs

Prostaglandin E<sub>1</sub>: Its Effects on Hepatic Circulation in Dogs

Physiological and pharmacological variability in estimated hepatic blood flow in man.

Adrenergic Mechanisms in the Hepatic Microcirculation in the Rat

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