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Evidence for a role of opioids in epoxyeicosatrienoic acid-induced cardioprotection in rat hearts. Am J Physiol Heart Circ Physiol 2010 Jun;298(6):H2201-7

Date

04/20/2010

Pubmed ID

20400686

Pubmed Central ID

PMC2886625

DOI

10.1152/ajpheart.00815.2009

Scopus ID

2-s2.0-77952663470   28 Citations

Abstract

We previously demonstrated that several epoxyeicosatrienoic acids (EETs) produce reductions in myocardial infarct size in rats and dogs. Since a recent study demonstrated the release of opioids in mediating the antinociceptive effect of 14,15-EET, we hypothesized that endogenous opioids may also be involved in mediating the cardioprotective effect of the EETs. To test this hypothesis, we used an in vivo rat model of infarction and a rat Langendorff model. In the infarct model, hearts were subjected to 30 min occlusion of the left coronary artery and 2 h reperfusion. Animals were treated with 11,12-EET or 14,15-EET (2.5 mg/kg) alone 15 min before occlusion or with opioid antagonists [naloxone, naltrindole, nor-binaltorphimine (nor-BNI), and d-Phe-Cys-Tyr-d-Trp-Om-Thr-Pen-Thr-NH(2) (CTOP), a nonselective, a selective delta, a selective kappa, and a selective mu receptor antagonist, respectively] 10 min before EET administration. In four separate groups, antiserum to Met- and Leu-enkephalin and dynorphin-A-(1-17) was administered 50 min before the 11,12-EET administration. Infarct size expressed as a percent of the area at risk (IS/AAR) was 63.5 + or - 1.2, 45.3 + or - 1.0, and 40.9 + or - 1.2% for control, 11,12-EET, and 14,15-EET, respectively. The protective effects of 11,12-EET were abolished by pretreatment with either naloxone (60.5 + or - 1.8%), naltrindole (60.8 + or - 1.0%), nor-BNI (62.3 + or - 2.8%), or Met-enkephalin antiserum (63.2 + or - 1.7%) but not CTOP (42.0 + or - 3.0%). In isolated heart experiments, 11,12-EET was administered to the perfusate 15 min before 20 min global ischemia followed by 45 min reperfusion in control hearts or in those pretreated with pertussis toxin (48 h). 11,12-EET increased the recovery of left ventricular developed pressure from 33 + or - 1 to 45 + or - 6% (P < 0.05) and reduced IS/AAR from 37 + or - 4 to 20 + or - 3% (P < 0.05). Both pertussis toxin and naloxone abolished these beneficial effects of 11,12-EET. Taken together, these results suggest that the major cardioprotective effects of the EETs depend on activation of a G(i/o) protein-coupled delta- and/or kappa-opioid receptor.

Author List

Gross GJ, Baker JE, Hsu A, Wu HE, Falck JR, Nithipatikom K

Author

John E. Baker PhD Professor in the Surgery department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

8,11,14-Eicosatrienoic Acid
Analgesics, Opioid
Animals
Disease Models, Animal
GTP-Binding Protein alpha Subunits, Gi-Go
Male
Myocardial Infarction
Myocardial Reperfusion Injury
Naloxone
Naltrexone
Narcotic Antagonists
Rats
Rats, Sprague-Dawley
Receptors, Opioid
Somatostatin
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a