J Korean Soc Emerg Med.  2012 Feb;23(1):111-119.

The Neuroprotective Effect of delta-opioid Receptor Stimulation with [D-Ala2, D-Leu5] Enkephalin Against Ischemic Neuronal Injury

• Kim H
• Lee SW
• Park JS
• Min JH
• Min MK

Abstract

PURPOSE
Oxygen is indispensable for survival and aerobic metabolism in all mammalian cells. Inadequate oxygen triggers a multifaceted cellular response negatively impacting important physiological functions which are observed in clinical diseases such as stroke, drowning, cardiac arrest, hazardous gas poisoning, myocardial infarction and vascular dementia. In this study, we investigated the neuroprotective effect of a synthetic delta-opioid agonist, [D-Ala2, D-Leu5] enkephalin (DADLE), and its role in ischemic neuronal injury.
METHODS
This experiment was conducted in vitro using a primary culture of rat cortical neurons. Ischemia induction was performed using a hypoxic chamber. To test the degree of neuronal viability, as protected by delta-opioid stimulation with DADLE under ischemia, we used three independent approaches including a lactate dehydrogenase assay, MTT assay, and an immunofluorescent staining assay for viable cells. In addition, the gene expressions of caspase-3 and heat shock protein 70 were analyzed using real-time PCR.
RESULTS
Incubation of the cortical neurons with DADLE protected them from ischemia-induced cytotoxicity, as observed by all three independent viability assays. Also, we found that its neuroprotective effect might be related with suppression of the caspase-3 gene.
CONCLUSION
The results of this study suggested that DADLE exhibits a neuroprotective effect against ischemia-induced neuronal cell death.

Keyword

Ischemia; [D-Ala2, D-Leu5] enkephalin (DADLE); Cortical neurons

MeSH Terms

Animals
Caspase 3
Cell Death
Dementia, Vascular
Drowning
Enkephalin, Leucine-2-Alanine
Enkephalins
Gas Poisoning
Gene Expression
Heart Arrest
HSP70 Heat-Shock Proteins
Ischemia
L-Lactate Dehydrogenase
Myocardial Infarction
Neurons
Neuroprotective Agents
Oxygen
Rats
Stroke
Caspase 3
Enkephalin, Leucine-2-Alanine
Enkephalins
HSP70 Heat-Shock Proteins
L-Lactate Dehydrogenase
Neuroprotective Agents
Oxygen