Prostacyclin and cerebral vessel relaxation

Area of Science:

• Vascular Pharmacology
• Cardiovascular Research

Background:

• Cerebral arterial spasm is a significant complication following subarachnoid hemorrhage.
• Various endogenous substances can induce arterial contractions, contributing to vasospasm.

Purpose of the Study:

• To investigate the efficacy of prostacyclin in reversing in vitro contractions of human basilar arteries.
• To determine the dose-dependent effects of prostacyclin against spasmogens implicated in cerebral arterial spasm.

Main Methods:

• Human basilar artery segments were contracted in vitro using agents like 5-hydroxytryptamine, noradrenaline, angiotensin II, PGF2 alpha, and U-46619.
• Prostacyclin was administered at varying concentrations (10^-10 to 10^-6 M) to assess reversal of induced contractions.
• The effect of prostacyclin was evaluated against both near-maximal and maximal contractile responses.

Main Results:

• Prostacyclin demonstrated a dose-related reversal of contractions induced by most spasmogenic agents.
• Contractions induced by maximal concentrations of angiotensin II and U-46619 showed the least reversal by prostacyclin.
• Prostacyclin also dose-dependently reversed contractions induced by thromboxane-A2 generated from guinea-pig lung.

Conclusions:

• Prostacyclin exhibits potent vasodilatory properties, physiologically antagonizing contractions of the human basilar artery.
• These findings suggest prostacyclin or stable analogues could be therapeutic agents for cerebral arterial spasm.
• Further research into prostacyclin analogues may yield treatments for post-subarachnoid hemorrhage vasospasm.