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The role of ATP and adenosine in the control of hepatic blood flow in the rabbit liver in vivo.

Browse DJ, Mathie RT, Benjamin IS, Alexander B - Comp Hepatol (2003)

Bottom Line: RESULTS: Hepatic arterial (HA) blood flow increased in response to reduced portal venous (PV) blood flow, the "buffer response", from 19.4 (3.3) ml min-1 100 g-1 to 25.6 (4.3) ml min-1 100 g-1 (mean (SE), p < 0.05, Student's paired t-test).Intra-portal injections of ATP or adenosine (1 micrograms kg-1-0.5 mg kg-1) elicited immediate increases in HA blood flow to give -log ED50 values of 2.0 and 1.7 mg kg-1 for ATP and adenosine respectively.Injection of ATP and adenosine had no measurable effect on PV flow.

View Article: PubMed Central - HTML - PubMed

Affiliation: Liver Sciences Unit, Academic Department of Surgery, GKT School of Medicine and Dentistry, St Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK. barry.alexander@kcl.ac.uk

ABSTRACT
BACKGROUND: The role of adenosine and ATP in the regulation of hepatic arterial blood flow in the "buffer response" was studied in vitro and in a new in vivo model in the rabbit. The model achieves portal-systemic diversion by insertion of a silicone rubber prosthesis between the portal vein and inferior vena cava and avoids alterations in systemic haemodynamics. RESULTS: Hepatic arterial (HA) blood flow increased in response to reduced portal venous (PV) blood flow, the "buffer response", from 19.4 (3.3) ml min-1 100 g-1 to 25.6 (4.3) ml min-1 100 g-1 (mean (SE), p < 0.05, Student's paired t-test). This represented a buffering capacity of 18.7 (5.2) %. Intra-portal injections of ATP or adenosine (1 micrograms kg-1-0.5 mg kg-1) elicited immediate increases in HA blood flow to give -log ED50 values of 2.0 and 1.7 mg kg-1 for ATP and adenosine respectively. Injection of ATP and adenosine had no measurable effect on PV flow. In vitro, using an isolated dual-perfused rabbit liver preparation, the addition of 8-phenyltheophylline (10 MicroMolar) to the HA and PV perfusate significantly inhibited the HA response to intra-arterial adenosine and to mid-range doses of intra-portal or intra-arterial ATP (p < 0.001). CONCLUSIONS: It is suggested that HA vasodilatation elicited by ATP may be partially mediated through activation of P1-purinoceptors following catabolism of ATP to adenosine.

No MeSH data available.


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The effect of intra-portal injection of (a) ATP and (b) adenosine on changes in hepatic arterial flow (Δ HAF) in vivo. Both agents increased hepatic arterial flow in a dose-dependent manner. The error bars in the graphs represent the SE.
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Figure 3: The effect of intra-portal injection of (a) ATP and (b) adenosine on changes in hepatic arterial flow (Δ HAF) in vivo. Both agents increased hepatic arterial flow in a dose-dependent manner. The error bars in the graphs represent the SE.

Mentions: In the 5 experiments described above HAF and PVF were stable for a sufficiently long period to allow the construction of dose-response curves for HA flow responses to intra-portal injection of adenosine or ATP. Intraportal injection of ATP and adenosine both caused immediate increases in HAF (Figure 3) and the -log ED50 values (calculated from the graph) for these agents were 2.0 mg kg-1 and 1.7 mg kg-1 for ATP and adenosine respectively. Injection of ATP and adenosine had no measurable effect on PV flow.


The role of ATP and adenosine in the control of hepatic blood flow in the rabbit liver in vivo.

Browse DJ, Mathie RT, Benjamin IS, Alexander B - Comp Hepatol (2003)

The effect of intra-portal injection of (a) ATP and (b) adenosine on changes in hepatic arterial flow (Δ HAF) in vivo. Both agents increased hepatic arterial flow in a dose-dependent manner. The error bars in the graphs represent the SE.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC305370&req=5

Figure 3: The effect of intra-portal injection of (a) ATP and (b) adenosine on changes in hepatic arterial flow (Δ HAF) in vivo. Both agents increased hepatic arterial flow in a dose-dependent manner. The error bars in the graphs represent the SE.
Mentions: In the 5 experiments described above HAF and PVF were stable for a sufficiently long period to allow the construction of dose-response curves for HA flow responses to intra-portal injection of adenosine or ATP. Intraportal injection of ATP and adenosine both caused immediate increases in HAF (Figure 3) and the -log ED50 values (calculated from the graph) for these agents were 2.0 mg kg-1 and 1.7 mg kg-1 for ATP and adenosine respectively. Injection of ATP and adenosine had no measurable effect on PV flow.

Bottom Line: RESULTS: Hepatic arterial (HA) blood flow increased in response to reduced portal venous (PV) blood flow, the "buffer response", from 19.4 (3.3) ml min-1 100 g-1 to 25.6 (4.3) ml min-1 100 g-1 (mean (SE), p < 0.05, Student's paired t-test).Intra-portal injections of ATP or adenosine (1 micrograms kg-1-0.5 mg kg-1) elicited immediate increases in HA blood flow to give -log ED50 values of 2.0 and 1.7 mg kg-1 for ATP and adenosine respectively.Injection of ATP and adenosine had no measurable effect on PV flow.

View Article: PubMed Central - HTML - PubMed

Affiliation: Liver Sciences Unit, Academic Department of Surgery, GKT School of Medicine and Dentistry, St Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK. barry.alexander@kcl.ac.uk

ABSTRACT
BACKGROUND: The role of adenosine and ATP in the regulation of hepatic arterial blood flow in the "buffer response" was studied in vitro and in a new in vivo model in the rabbit. The model achieves portal-systemic diversion by insertion of a silicone rubber prosthesis between the portal vein and inferior vena cava and avoids alterations in systemic haemodynamics. RESULTS: Hepatic arterial (HA) blood flow increased in response to reduced portal venous (PV) blood flow, the "buffer response", from 19.4 (3.3) ml min-1 100 g-1 to 25.6 (4.3) ml min-1 100 g-1 (mean (SE), p < 0.05, Student's paired t-test). This represented a buffering capacity of 18.7 (5.2) %. Intra-portal injections of ATP or adenosine (1 micrograms kg-1-0.5 mg kg-1) elicited immediate increases in HA blood flow to give -log ED50 values of 2.0 and 1.7 mg kg-1 for ATP and adenosine respectively. Injection of ATP and adenosine had no measurable effect on PV flow. In vitro, using an isolated dual-perfused rabbit liver preparation, the addition of 8-phenyltheophylline (10 MicroMolar) to the HA and PV perfusate significantly inhibited the HA response to intra-arterial adenosine and to mid-range doses of intra-portal or intra-arterial ATP (p < 0.001). CONCLUSIONS: It is suggested that HA vasodilatation elicited by ATP may be partially mediated through activation of P1-purinoceptors following catabolism of ATP to adenosine.

No MeSH data available.


Related in: MedlinePlus