Endothelin-1(1-31) induces spreading depolarization in rats

Area of Science:

• Neuroscience
• Pharmacology
• Cerebrovascular Physiology

Background:

• Endothelin-1 (ET-1) induces cerebral vasospasm and spreading depolarization (SD) post-aneurysmal subarachnoid hemorrhage (aSAH).
• ET-1(1-31) is an alternate metabolic intermediate in ET-1 generation.
• Investigating ET-1(1-31)'s role in SD is crucial for understanding aSAH pathophysiology.

Purpose of the Study:

• To compare the efficacy of ET-1(1-31) and ET-1 in inducing SD.
• To evaluate ET-1(1-31) as a potential therapeutic target in aSAH.

Main Methods:

• Topical brain application of increasing ET-1, ET-1(1-31), or vehicle concentrations in 29 rats.
• Recording of regional cerebral blood flow (rCBF) and direct current electrocorticogram (DC-ECoG) during superfusion.
• Statistical analysis using two-tailed Fisher's Exact Test to compare SD induction efficacy.

Main Results:

• Both ET-1 and ET-1(1-31) induced SD at 10(-6) M.
• ET-1 was significantly more potent in inducing SD at concentrations below 10(-6) M (P<0.001).
• ET-1(1-31) demonstrated significantly lower efficacy in inducing SD compared to ET-1.

Conclusions:

• ET-1(1-31) is less potent than ET-1 in inducing SD, suggesting it's a weaker vasoconstrictor.
• ET-1(1-31) may represent a safer therapeutic target than ET-1 post-aSAH.
• Shifting metabolism towards ET-1(1-31) could mitigate ET-1-induced vasoconstriction and SD while preserving beneficial ETA receptor activation.