Alterations of Voltage-Dependent Calcium Channel Currents in Basilar Artery Smooth Muscle Cells at Early Stage of Subarachnoid Hemorrhage in a Rabbit Model

Xianqing Shi,Yongjian Fu,Daqing Liao,Yanfang Chen,Jin Liu

doi:10.1371/journal.pone.0084129

Abstract

ObjectiveTo investigate the changes in the currents of voltage-dependent calcium channels (VDCCs) in smooth muscle cells of basilar artery in a rabbit model of subarachnoid hemorrhage (SAH).MethodsNew Zealand white rabbits were randomly divided into five groups: sham (C), normal (N), 24 hours (S1), 48 hours (S2) and 72 hours (S3) after SAH. Non-heparinized autologous arterial blood (1ml/kg) was injected into the cisterna magna to create SAH after intravenous anesthesia, and 1 ml/kg of saline was injected into cisterna magna in the sham group. Rabbits in group N received no injections. Basilar artery in S1, S2, S3 group were isolated at 24, 48, 72 hours after SAH. Basilar artery in group C was isolated at 72 hours after physiological saline injection. Basilar artery smooth muscle cells were isolated for all groups. Whole-cell patch-clamp technique was utilized to record cell membrane capacitance and VDCCs currents. The VDCCs antagonist nifedipine was added to the bath solution to block the Ca++ channels currents.ResultsThere were no significant differences in the number of cells isolated, the cell size and membrane capacitance among all the five groups. VDCC currents in the S1–S3 groups had higher amplitudes than those in control and sham groups. The significant change of current amplitude was observed at 72 hours after SAH, which was higher than those of 24 and 48 hours. The VDCCs were shown to expression in human artery smooth muscle cells.ConclusionsThe changes of activation characteristics and voltage-current relationship at 72 hours after SAH might be an important event which leads to a series of molecular events in the microenvironment of the basilar artery smooth muscle cells. This may be the key time point for potential therapeutic intervention against subarachnoid hemorrhage.

Highlights

When a cerebral aneurysm ruptures, bleeding and clot formation occur around the surface of the brain, including several major blood vessels
Mechanisms contributing to the development of vasospasm have been investigated in recent years and the studies demonstrated that Cerebral vasospasm (CVS) have relationship with the disorder of ion channels in cerebral vessels after subarachnoid hemorrhage (SAH) [3,4,5]
There were no significant differences in heart rate (HR) and Mean arterial pressure (MAP) in all groups prior to and at 30 minutes after SAH (P.0.05) (Table 1)

Summary

Introduction

When a cerebral aneurysm ruptures, bleeding and clot formation occur around the surface of the brain, including several major blood vessels. Cerebral vasospasm (CVS) and the resulting cerebral ischemia occurring after subarachnoid hemorrhage (SAH) are responsible for the considerable morbidity and mortality [1]. Mechanisms contributing to the development of vasospasm have been investigated in recent years and the studies demonstrated that CVS have relationship with the disorder of ion channels in cerebral vessels after SAH [3,4,5]. VDCCs serve as a main potential-dependent Ca2+ entry pathway in a wide range of tissues/cell types and have been implicated in a variety of cellular processes including oxidative stress, mitochondrial dysfunction and cell death in neuronal dysfunction [10,11,12]

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