Local anesthetics inhibit endothelium-dependent vasodilation

Area of Science:

• Pharmacology
• Cardiovascular Physiology
• Endothelial Function

Background:

• Endothelium-dependent vasodilation is crucial for vascular health.
• Local anesthetics are widely used but can have systemic effects.
• Understanding their impact on vascular function is important.

Purpose of the Study:

• To investigate the effects of common local anesthetics on endothelium-dependent and endothelium-independent vasodilation.
• To determine if local anesthetics interfere with specific signaling pathways involved in vasodilation.

Main Methods:

• Isolated rat thoracic aorta rings were used for isometric tension recording.
• Vascular relaxation responses to methacholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) were measured.
• Responses were assessed in the presence of bupivacaine, lidocaine, etidocaine, or 2-chloroprocaine.

Main Results:

• All tested local anesthetics significantly inhibited endothelium-dependent vasodilation induced by methacholine and A23187.
• Bupivacaine demonstrated greater potency in inhibiting these relaxations compared to other anesthetics.
• Endothelium-independent vasodilation induced by sodium nitroprusside remained unaffected by the local anesthetics.

Conclusions:

• Local anesthetics impair endothelium-dependent vasodilation through a mechanism downstream of endothelial cell receptor activation.
• The inhibitory effect occurs before guanylate cyclase activation in vascular smooth muscle.
• These findings highlight a specific vascular action of local anesthetics.