Isoflurane favorably modulates guanosine triphosphate cyclohydrolase-1 and endothelial nitric oxide synthase during myocardial ischemia and reperfusion injury in rats. Anesthesiology 2015 Sep;123(3):582-9
Date
07/21/2015Pubmed ID
26192027Pubmed Central ID
PMC4543441DOI
10.1097/ALN.0000000000000778Scopus ID
2-s2.0-84964697044 (requires institutional sign-in at Scopus site) 10 CitationsAbstract
BACKGROUND: The authors investigated the hypothesis that isoflurane modulates nitric oxide (NO) synthesis and protection against myocardial infarction through time-dependent changes in expression of key NO regulatory proteins, guanosine triphosphate cyclohydrolase (GTPCH)-1, the rate-limiting enzyme involved in the biosynthesis of tetrahydrobiopterin and endothelial nitric oxide synthase (eNOS).
METHODS: Myocardial infarct size, NO production (ozone-mediated chemiluminescence), GTPCH-1, and eNOS expression (real-time reverse transcriptase polymerase chain reaction and western blotting) were measured in male Wistar rats with or without anesthetic preconditioning (APC; 1.0 minimum alveolar concentration isoflurane for 30 min) and in the presence or absence of an inhibitor of GTPCH-1, 2,4-diamino-6-hydroxypyrimidine.
RESULTS: NO2 production (158 ± 16 and 150 ± 13 pmol/mg protein at baseline in control and APC groups, respectively) was significantly (P < 0.05) increased 1.5 ± 0.1 and 1.4 ± 0.1 fold by APC (n = 4) at 60 and 90 min of reperfusion, respectively, concomitantly, with increased expression of GTPCH-1 (1.3 ± 0.3 fold; n = 5) and eNOS (1.3 ± 0.2 fold; n = 5). In contrast, total NO (NO2 and NO3) was decreased after reperfusion in control experiments. Myocardial infarct size was decreased (43 ± 2% of the area at risk for infarction; n = 6) by APC compared with control experiments (57 ± 1%; n = 6). 2, 4-Diamino-6-hydroxypyrimidine decreased total NO production at baseline (221 ± 25 and 175 ± 31 pmol/mg protein at baseline in control and APC groups, respectively), abolished isoflurane-induced increases in NO at reperfusion, and prevented reductions of myocardial infarct size by APC (60 ± 2%; n = 6).
CONCLUSION: APC favorably modulated a NO biosynthetic pathway by up-regulating GTPCH-1 and eNOS, and this action contributed to protection of myocardium against ischemia and reperfusion injury.
Author List
Baotic I, Weihrauch D, Procknow J, Vasquez-Vivar J, Ge ZD, Sudhakaran S, Warltier DC, Kersten JRAuthors
Jeannette M. Vasquez-Vivar PhD Professor in the Biophysics department at Medical College of WisconsinDorothee Weihrauch DVM, PhD Research Scientist II in the Anesthesiology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
Anesthetics, InhalationAnimals
GTP Cyclohydrolase
Isoflurane
Male
Myocardial Ischemia
Myocardial Reperfusion Injury
Nitric Oxide Synthase Type III
Random Allocation
Rats
Rats, Wistar