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Role of Endogenous Opioid System in Ischemic-Induced Late Preconditioning.

Fraessdorf J, Hollmann MW, Hanschmann I, Heinen A, Weber NC, Preckel B, Huhn R - PLoS ONE (2015)

Bottom Line: We investigated whether 1) OR are involved in the trigger and/or mediation phase of LPC and 2) a time course effect on the expression of different opioid receptors and their endogenous ligands exists.LPC reduced infarct size from 61±10% in controls to 25±9% (P<0.001).Expression of δ-OR and plasma levels of endogenous opioid peptides are increased after ischemic LPC.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany; Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Academic Medical Center (AMC), University of Amsterdam, Amsterdam, The Netherlands.

ABSTRACT

Background: Opioid receptors (OR) are involved in myocardial late preconditioning (LPC) induced by morphine and δ1-opioid receptor (δ1-OR) agonists. The role of OR in ischemic-induced LPC is unknown. We investigated whether 1) OR are involved in the trigger and/or mediation phase of LPC and 2) a time course effect on the expression of different opioid receptors and their endogenous ligands exists.

Methods: Male Wistar rats were randomly allocated to four groups (each group n = 8). Awake animals were ischemic preconditioned by a 5 minutes coronary occlusion. 24 hours later, anesthetized animals underwent 25 minutes coronary occlusion followed by 2 hours of reperfusion. The role of OR was investigated by treatment with intraperitoneal naloxone (Nal) 10 minutes prior to LPC (Nal-LPC; trigger phase) or 10 min prior to sustained ischemia (LPC-Nal; mediation phase).

Results: LPC reduced infarct size from 61±10% in controls to 25±9% (P<0.001). Naloxone during trigger or mediation phase completely abolished LPC-induced cardioprotection (59±9% and 62±9%; P<0.001 vs. LPC). 8, 12 and 24 hours after the ischemic stimulus, expression of δ-OR in the heart was increased, whereas μ-opioid receptor (μ-OR) and κ-opioid receptor (κ-OR) were not. Plasma concentrations of β-endorphin and leu-enkephalin but not dynorphin were increased by LPC.

Conclusion: Ischemic LPC is triggererd and mediated by OR. Expression of δ-OR and plasma levels of endogenous opioid peptides are increased after ischemic LPC.

No MeSH data available.


Related in: MedlinePlus

Experimental protocol for infarct size measurements and molecular biology.Con = control, LPC = late preconditioning, Nal = naloxone (1 mg/kg), (T) = trigger phase, (M) = mediation phase.
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pone.0134283.g001: Experimental protocol for infarct size measurements and molecular biology.Con = control, LPC = late preconditioning, Nal = naloxone (1 mg/kg), (T) = trigger phase, (M) = mediation phase.

Mentions: Male Wistar rats had free access to water and standard rat food at all times prior to experiments. The animal preparation was performed as described previously [5]. The animals (305±12 g) were instrumented with a coronary occluder around a left anterior descending artery. 7 days after recovery, animals were randomly allocated into four groups (by sealed envelopes; each group n = 8, Fig 1). Awake animals were ischemic preconditioned by a 5 minute coronary artery occlusion. 24 hours later, chloralose-anesthetized animals were endotracheally intubated with a plastic cannula (outer diameter 2.2 mm). After a median incision at the cervical level was performed a 20 gauge cannula was inserted into the right internal carotid artery and advanced into the aorta in order to measure aortic pressure. Aortic pressure was digitized using an analogue to digital converter (PowerLab/8SP, ADInstruments Pty Ltd, Castle Hill, Australia) at a sampling rate of 500 Hz and were continuously recorded on a personal computer using Chart for Windows v5.0 (ADInstruments Pty Ltd, Castle Hill, Australia). All animals underwent 25 minutes of coronary artery occlusion followed by 2 hours of reperfusion. At the end of reperfusion the hearts were excised and infarct sizes were determined using a previously described method [5]. Briefly, the heart was excised with the occluding suture left in place and then mounted on a modified Langendorff apparatus for perfusion with ice cold normal saline via the aortic root at a perfusion pressure of 80 cm H2O in order to wash out intravascular blood. After 5 minutes of perfusion, the coronary artery was re-occluded and the remainder of the myocardium was perfused through the aortic root with 0.2% Evans blue in normal saline for 10 minutes. Intravascular Evans blue was then washed out by perfusion with normal saline for 10 min. This treatment identified the area at risk as unstained. The heart was then cut into 2 mm thick transverse slices. The slices were stained with 0.75% triphenyltetrazolium chloride (TTC) solution for 10 minutes at 37°C, and fixed in 4% formalin solution for 24 hours at room temperature. The area at risk and the infarct size were determined using planimetry and corrected for dry weight in each slice by using SigmaScan Pro5 (SPSS Science Software, Chicago, IL, USA).


Role of Endogenous Opioid System in Ischemic-Induced Late Preconditioning.

Fraessdorf J, Hollmann MW, Hanschmann I, Heinen A, Weber NC, Preckel B, Huhn R - PLoS ONE (2015)

Experimental protocol for infarct size measurements and molecular biology.Con = control, LPC = late preconditioning, Nal = naloxone (1 mg/kg), (T) = trigger phase, (M) = mediation phase.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4520665&req=5

pone.0134283.g001: Experimental protocol for infarct size measurements and molecular biology.Con = control, LPC = late preconditioning, Nal = naloxone (1 mg/kg), (T) = trigger phase, (M) = mediation phase.
Mentions: Male Wistar rats had free access to water and standard rat food at all times prior to experiments. The animal preparation was performed as described previously [5]. The animals (305±12 g) were instrumented with a coronary occluder around a left anterior descending artery. 7 days after recovery, animals were randomly allocated into four groups (by sealed envelopes; each group n = 8, Fig 1). Awake animals were ischemic preconditioned by a 5 minute coronary artery occlusion. 24 hours later, chloralose-anesthetized animals were endotracheally intubated with a plastic cannula (outer diameter 2.2 mm). After a median incision at the cervical level was performed a 20 gauge cannula was inserted into the right internal carotid artery and advanced into the aorta in order to measure aortic pressure. Aortic pressure was digitized using an analogue to digital converter (PowerLab/8SP, ADInstruments Pty Ltd, Castle Hill, Australia) at a sampling rate of 500 Hz and were continuously recorded on a personal computer using Chart for Windows v5.0 (ADInstruments Pty Ltd, Castle Hill, Australia). All animals underwent 25 minutes of coronary artery occlusion followed by 2 hours of reperfusion. At the end of reperfusion the hearts were excised and infarct sizes were determined using a previously described method [5]. Briefly, the heart was excised with the occluding suture left in place and then mounted on a modified Langendorff apparatus for perfusion with ice cold normal saline via the aortic root at a perfusion pressure of 80 cm H2O in order to wash out intravascular blood. After 5 minutes of perfusion, the coronary artery was re-occluded and the remainder of the myocardium was perfused through the aortic root with 0.2% Evans blue in normal saline for 10 minutes. Intravascular Evans blue was then washed out by perfusion with normal saline for 10 min. This treatment identified the area at risk as unstained. The heart was then cut into 2 mm thick transverse slices. The slices were stained with 0.75% triphenyltetrazolium chloride (TTC) solution for 10 minutes at 37°C, and fixed in 4% formalin solution for 24 hours at room temperature. The area at risk and the infarct size were determined using planimetry and corrected for dry weight in each slice by using SigmaScan Pro5 (SPSS Science Software, Chicago, IL, USA).

Bottom Line: We investigated whether 1) OR are involved in the trigger and/or mediation phase of LPC and 2) a time course effect on the expression of different opioid receptors and their endogenous ligands exists.LPC reduced infarct size from 61±10% in controls to 25±9% (P<0.001).Expression of δ-OR and plasma levels of endogenous opioid peptides are increased after ischemic LPC.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany; Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Academic Medical Center (AMC), University of Amsterdam, Amsterdam, The Netherlands.

ABSTRACT

Background: Opioid receptors (OR) are involved in myocardial late preconditioning (LPC) induced by morphine and δ1-opioid receptor (δ1-OR) agonists. The role of OR in ischemic-induced LPC is unknown. We investigated whether 1) OR are involved in the trigger and/or mediation phase of LPC and 2) a time course effect on the expression of different opioid receptors and their endogenous ligands exists.

Methods: Male Wistar rats were randomly allocated to four groups (each group n = 8). Awake animals were ischemic preconditioned by a 5 minutes coronary occlusion. 24 hours later, anesthetized animals underwent 25 minutes coronary occlusion followed by 2 hours of reperfusion. The role of OR was investigated by treatment with intraperitoneal naloxone (Nal) 10 minutes prior to LPC (Nal-LPC; trigger phase) or 10 min prior to sustained ischemia (LPC-Nal; mediation phase).

Results: LPC reduced infarct size from 61±10% in controls to 25±9% (P<0.001). Naloxone during trigger or mediation phase completely abolished LPC-induced cardioprotection (59±9% and 62±9%; P<0.001 vs. LPC). 8, 12 and 24 hours after the ischemic stimulus, expression of δ-OR in the heart was increased, whereas μ-opioid receptor (μ-OR) and κ-opioid receptor (κ-OR) were not. Plasma concentrations of β-endorphin and leu-enkephalin but not dynorphin were increased by LPC.

Conclusion: Ischemic LPC is triggererd and mediated by OR. Expression of δ-OR and plasma levels of endogenous opioid peptides are increased after ischemic LPC.

No MeSH data available.


Related in: MedlinePlus