Cerebral hemodynamics during cortical spreading depression in rabbits

Area of Science:

• Neuroscience
• Cerebrovascular Physiology

Background:

• Cortical spreading depression (CSD) is a wave of neuronal and glial depolarization that spreads across the cerebral cortex.
• Understanding the cerebrovascular response to CSD is crucial for comprehending neurological conditions like migraine and stroke.

Purpose of the Study:

• To investigate the effects of a single CSD on the diameter of pial arterioles and venules.
• To analyze the relationship between CSD propagation and vascular diameter changes.
• To examine the influence of CSD laterality and indomethacin on these vascular responses.

Main Methods:

• CSD was induced by KCl microinjection in urethane-anesthetized rabbits using a closed cranial window.
• Pial arteriole and venule diameters were measured in real-time during CSD propagation.
• Vascular responses were analyzed in relation to CSD location, velocity, and timing.
• The effect of indomethacin pretreatment on vascular diameter was assessed.

Main Results:

• Most pial arterioles (except retrosplenial) significantly dilated during ipsilateral CSD, with smaller arterioles showing greater percentage increase.
• Venules showed variable dilation, with smaller ones dilating more than larger ones, often after peak arteriolar dilation.
• Pial arterioles exhibited significant constriction during contralateral CSD.
• Indomethacin pretreatment markedly enhanced arteriolar dilation during CSD.

Conclusions:

• CSD significantly impacts pial arteriolar and venular diameters, with distinct responses based on vessel size and CSD laterality.
• The findings suggest a close temporal and spatial association between CSD and cerebrovascular diameter changes.
• Indomethacin may play a role in modulating the vascular response to CSD.