Phenylephrine induces delayed cardioprotection against necrosis without amelioration of stunning.

Published

Journal Article

BACKGROUND: Alpha-adrenergic stimulation induces protection in reperfused ischemic (I/R) myocardium 24 hours later. We tested the hypothesis that phenylephrine improves dysfunction after global I/R by limiting cell death not stunning. METHODS: Rabbits were pretreated with either phenylephrine or vehicle. Twenty-four hours later, isolated hearts underwent either 45 (infarction protocol) or 20 minutes (stunning protocol) of global ischemia before 2 hours of reperfusion (n = 6 per group). Cell death was determined by triphenyl tetrazolium chloride staining (infarction) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) (apoptosis). RESULTS: Compared with vehicle, phenylephrine pretreatment improved post-I/R-developed pressures in hearts after infarction (53.2 +/- 4.0 vs 35.8 +/- 4.1 mm Hg, p = 0.01) but not stunning protocol (64.3 +/- 8.9 vs 57.7 +/- 6.2 mm Hg, p = NS). The improved developed pressure was due to better diastolic recovery. Systolic pressures were similar between groups. Phenylephrine markedly decreased infarction (9.0 +/- 1.9% vs 40.8 +/- 1.8% for vehicle, p < 0.001) and TUNEL-positive staining. Stunned hearts of either group had less than 3% infarction and no apoptosis. CONCLUSIONS: Phenylephrine pretreatment 24 hours before global I/R improves function by limiting infarction but not stunning.

Full Text

Duke Authors

Cited Authors

  • Baghelai, K; Graham, LJ; Wechsler, AS; Jakoi, ER

Published Date

  • October 1999

Published In

Volume / Issue

  • 68 / 4

Start / End Page

  • 1219 - 1224

PubMed ID

  • 10543482

Pubmed Central ID

  • 10543482

Electronic International Standard Serial Number (EISSN)

  • 1552-6259

International Standard Serial Number (ISSN)

  • 0003-4975

Digital Object Identifier (DOI)

  • 10.1016/s0003-4975(99)00979-0

Language

  • eng