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Role of endothelin-1 (ET-1) in dog myocardial ischaemia-reperfusion
Pharmacological
354
Research, Vol. 30, No. 4, 1994
ROLE OF LEUKOCYTE AND PLATELET ACTIVATING FACTOR IN SPLANCHNIC ARTERY OCCLUSION (SAO) SHOCK IN THE RAT P. CANALE,
F. SQUADRITO, M. IOCULANO, G. M. CAMP0
D. ALTAVILLA
Caputi A. P. Institute of Pharmacology, School of Medicine, Messina, Italy
and
University of
We investigated the adhesion of leukocytes in the ileum and lung during SAO shock and the role of platelet activating factor (PAF) and tumor necrosis factor (TNF-a). Rats were subjected to 45 min of splanchnic arteries occlusion followed by reperfusion. SAO shocked rats died within 90 min after release of arteries. The neutrophilic infiltrate was quantified using the myeloperoxidase (MPO) assay. MPO activity in the ileum and in the lung averaged 0.0.5+0.03 and 0.4kO.2 U (g protein)-’ in animals killed before occlusion, did not change in those killed immediately before reperfusion and was significantly elevated (0.11 f0.023 and 1.7f0.6 U (g protein)-’ in the ileum and lung, respectively) in those killed 80 min after the beginning of the reperfusion. The histological examination confirmed the accumulation of leukocyte in the ileum mucosa and lung over the 80 min. TNF-a was measured in serum by using biological assay, based on the killing of L929 mouse tumor cells. Serum TNF-a undetectable in sham-shocked rats, rose up to 93 f7 U mll’ in shocked rats. SAO shocked rats exhibited leukopenia (3.2&0.6x 10’ mm-‘). To evaluate the role of PAF and TNF-a, a PAF receptor antagonist TCV-309 (5 ,ug kg-’ i.v.) was injected 5 min after reperfusion. TV-309 increased survival time, lowered serum levels of TNF-ar, reduced MPO activity in both ileum and lung and ameliorated leukopenia induced by SAO shock. In addition the drug significantly reduced ileum necrosis and lung morphological alterations induced by shock. The results suggest the important role of PAF and TNF-a in the adhesion of leukocyte in SAO shock.
ROLE OF ENDOTHELIN-1 (ET-l) IN DOG MYOCARDIAL ISCHAEMIA-REPERFUSION L. BERRINO,
V. DE NOVELLIS,
A. FILIPPELLI, F. ROSS1
A. PALLA,
M. D’AMICO
and
Institute of Pharmacology and Toxicology, Faculty of Medicine and Surgery, II University of Naples, Italy Elevated ET-l plasma levels have been found in cardiovascular disorders such as acute myocardial infarction, angina pectoris, severe hypertension and cardiogenic shock. Furthermore, the administration of nanomolar doses of ET-l in the
pharmacological
Research,
35s
Vol. 30. No, 4, 1994
coronary arteries produces a response pattern similar to that observed during the experimentally-induced myocardial ischaemia. In this study we examined plasma ET-l levels (PET-1) in beagles pretreated with diltiazem (DZ) (0.1 and 1 mg kg-’ by intravenous route, i.v.) or nitroglycerin (NTG) (0.5 and 1 mg kg-’ i.v.). Anaesthetized (natrium penthobarbital 25 mg kg-’ i.v.) open-chest dogs underwent to 30 min occlusion of the left anterior descending coronary artery following by disocclusion (reperfusion state). PET-1 from coronary sinus were evaluated by radioimmunoassay 0 (1.8f0.3 pg ml-‘), 5 and 30 min after occlusion and just after disocclusion. PET-1 peaked at 30 min (5.3+ 0.8 pg ml-‘) after occlusion, and returned to baseline within 5 min after reperfusion; during this phase we observed tachycardia and ventricular fibrillation and intraventricular block. Pretreatment with NTG attenuates neither the increase in PET-1 nor reperfusion-arrhythmias, whereas pretreatment with DZ (1 mg kg-’ i.v.) significantly reduced both plasma ET-l level during ischaemia and reperfusion-arrhythmias. It is therefore conceivable that the release of ET-l from endothelium during occlusion phase, may play a role in myocardial ischaemia. It is also remarkable that the protective action of DZ on the ischaemia-reperfusion damages parallels the reduction of PET- 1.
PATHOPHYSIOLOGY OF LEUKOCYTES: FROM INFLAMMATION TO ISCHAEMIA-REPERFUSION SYNDROME SANDRA
BRUNELLESCHI”,
ILARIO
VIANOt
and ROBERTO
FANTOZZI*$
“Centro Interuniversitario “tpossie”, clo Department of Pharmacology, University of Florence, Florence, Italy; tDepartment of Medical Sciences, University of Turin, Novara, Italy; Slnstitute of Pharmacology and Pharmacognosy, University of Turin, Turin, Italy. We demonstrated [l] that polymorphonuclear leukocytes (PMNs), isolated from patients undergoing arterial reconstruction with temporary aortic occlusion, presented a reduced respiratory burst at the end of ischaemia, while an increased superoxide anion (02-) production was detected at reperfusion. In vitro, challenge of PMNs with different combinations of stimuli may result in primed or synergistic activation. Such in vitro models have been developed to reproduce in vivo conditions in which PMNs are concomitantly exposed to different mediators and are regarded as good tools to investigate drugs’ effects on PMN functioning. Substance P (SP) dose-dependently enhanced 02- production from human PMNs stimulated by platelet activating factor (PAF) [2]. WEB 2086, a PAF receptor antagonist, dose-dependently reduced 02- production from PMNs challenged with SP+PAF, as did pentoxyfilline, a xanthine derivative, whose ability to inhibit PAF-primed PMNs was previously reported. Adenosine Al and A2 receptors are present on PMN membrane: A2 receptors are invoIved in inhibition of the
354
Research, Vol. 30, No. 4, 1994
ROLE OF LEUKOCYTE AND PLATELET ACTIVATING FACTOR IN SPLANCHNIC ARTERY OCCLUSION (SAO) SHOCK IN THE RAT P. CANALE,
F. SQUADRITO, M. IOCULANO, G. M. CAMP0
D. ALTAVILLA
Caputi A. P. Institute of Pharmacology, School of Medicine, Messina, Italy
and
University of
We investigated the adhesion of leukocytes in the ileum and lung during SAO shock and the role of platelet activating factor (PAF) and tumor necrosis factor (TNF-a). Rats were subjected to 45 min of splanchnic arteries occlusion followed by reperfusion. SAO shocked rats died within 90 min after release of arteries. The neutrophilic infiltrate was quantified using the myeloperoxidase (MPO) assay. MPO activity in the ileum and in the lung averaged 0.0.5+0.03 and 0.4kO.2 U (g protein)-’ in animals killed before occlusion, did not change in those killed immediately before reperfusion and was significantly elevated (0.11 f0.023 and 1.7f0.6 U (g protein)-’ in the ileum and lung, respectively) in those killed 80 min after the beginning of the reperfusion. The histological examination confirmed the accumulation of leukocyte in the ileum mucosa and lung over the 80 min. TNF-a was measured in serum by using biological assay, based on the killing of L929 mouse tumor cells. Serum TNF-a undetectable in sham-shocked rats, rose up to 93 f7 U mll’ in shocked rats. SAO shocked rats exhibited leukopenia (3.2&0.6x 10’ mm-‘). To evaluate the role of PAF and TNF-a, a PAF receptor antagonist TCV-309 (5 ,ug kg-’ i.v.) was injected 5 min after reperfusion. TV-309 increased survival time, lowered serum levels of TNF-ar, reduced MPO activity in both ileum and lung and ameliorated leukopenia induced by SAO shock. In addition the drug significantly reduced ileum necrosis and lung morphological alterations induced by shock. The results suggest the important role of PAF and TNF-a in the adhesion of leukocyte in SAO shock.
ROLE OF ENDOTHELIN-1 (ET-l) IN DOG MYOCARDIAL ISCHAEMIA-REPERFUSION L. BERRINO,
V. DE NOVELLIS,
A. FILIPPELLI, F. ROSS1
A. PALLA,
M. D’AMICO
and
Institute of Pharmacology and Toxicology, Faculty of Medicine and Surgery, II University of Naples, Italy Elevated ET-l plasma levels have been found in cardiovascular disorders such as acute myocardial infarction, angina pectoris, severe hypertension and cardiogenic shock. Furthermore, the administration of nanomolar doses of ET-l in the
pharmacological
Research,
35s
Vol. 30. No, 4, 1994
coronary arteries produces a response pattern similar to that observed during the experimentally-induced myocardial ischaemia. In this study we examined plasma ET-l levels (PET-1) in beagles pretreated with diltiazem (DZ) (0.1 and 1 mg kg-’ by intravenous route, i.v.) or nitroglycerin (NTG) (0.5 and 1 mg kg-’ i.v.). Anaesthetized (natrium penthobarbital 25 mg kg-’ i.v.) open-chest dogs underwent to 30 min occlusion of the left anterior descending coronary artery following by disocclusion (reperfusion state). PET-1 from coronary sinus were evaluated by radioimmunoassay 0 (1.8f0.3 pg ml-‘), 5 and 30 min after occlusion and just after disocclusion. PET-1 peaked at 30 min (5.3+ 0.8 pg ml-‘) after occlusion, and returned to baseline within 5 min after reperfusion; during this phase we observed tachycardia and ventricular fibrillation and intraventricular block. Pretreatment with NTG attenuates neither the increase in PET-1 nor reperfusion-arrhythmias, whereas pretreatment with DZ (1 mg kg-’ i.v.) significantly reduced both plasma ET-l level during ischaemia and reperfusion-arrhythmias. It is therefore conceivable that the release of ET-l from endothelium during occlusion phase, may play a role in myocardial ischaemia. It is also remarkable that the protective action of DZ on the ischaemia-reperfusion damages parallels the reduction of PET- 1.
PATHOPHYSIOLOGY OF LEUKOCYTES: FROM INFLAMMATION TO ISCHAEMIA-REPERFUSION SYNDROME SANDRA
BRUNELLESCHI”,
ILARIO
VIANOt
and ROBERTO
FANTOZZI*$
“Centro Interuniversitario “tpossie”, clo Department of Pharmacology, University of Florence, Florence, Italy; tDepartment of Medical Sciences, University of Turin, Novara, Italy; Slnstitute of Pharmacology and Pharmacognosy, University of Turin, Turin, Italy. We demonstrated [l] that polymorphonuclear leukocytes (PMNs), isolated from patients undergoing arterial reconstruction with temporary aortic occlusion, presented a reduced respiratory burst at the end of ischaemia, while an increased superoxide anion (02-) production was detected at reperfusion. In vitro, challenge of PMNs with different combinations of stimuli may result in primed or synergistic activation. Such in vitro models have been developed to reproduce in vivo conditions in which PMNs are concomitantly exposed to different mediators and are regarded as good tools to investigate drugs’ effects on PMN functioning. Substance P (SP) dose-dependently enhanced 02- production from human PMNs stimulated by platelet activating factor (PAF) [2]. WEB 2086, a PAF receptor antagonist, dose-dependently reduced 02- production from PMNs challenged with SP+PAF, as did pentoxyfilline, a xanthine derivative, whose ability to inhibit PAF-primed PMNs was previously reported. Adenosine Al and A2 receptors are present on PMN membrane: A2 receptors are invoIved in inhibition of the