Effects of a new magnesium-rich artificial cerebrospinal fluid on contractile 5-hydroxytryptamine and endothelin receptors in rat cerebral arteries

ABSTRACT

Objectives Cerebral vasospasm after subarachnoid haemorrhage (SAH) is associated with cerebrovascular contractile receptor upregulation resulted from haemolysis in the subarachnoid space. This study developed a new magnesium-rich artificial cerebrospinal fluid (MACSF) formula and investigated its effects on receptor-mediated contraction in rat basilar arteries.

Methods Clear and haemorrhagic cerebrospinal fluid (CSF) were collected from patients with hydrocephalus or SAH. MACSF was freshly prepared using clinical intravenous injections. Rat basilar arteries were segmented and incubated with clear CSF, haemorrhagic CSF or MACSF. The contractile responses were studied by myograph. The messenger ribonucleic acid (mRNA) and protein expression of 5-hydroxytryptamine 1B (5-HT_1B), endothelin subtype B (ET_B) and endothelin subtype A (ET_A) receptors were evaluated by real-time polymerase chain reaction (PCR) and Western blot analyses.

Results Haemorrhagic CSF exposure shifted the contractile curves induced by 5-hydroxytryptamine (5-HT), sarafotoxins 6c (S6c) and endothelin-1 (ET-1) leftward with increased maximal contraction values. Furthermore, mRNA and protein expression were markedly elevated for 5-HT_1B, ET_B and ET_A receptors on arteries exposed to haemorrhagic CSF. However, the contractile responses to 5-HT, S6c or ET-1 and expression of 5-HT_1B, ET_B and ET_A receptors in rat cerebral arteries exposed to MACSF remained unaffected compared to those exposed to clear CSF. Besides, unlike normal saline which can inactive in-vitro vessels, MACSF can maintain their physiological activity.

Conclusion Haemorrhagic CSF induces upregulation of 5-HT_1B, ET_B and ET_A receptors in rat cerebral arteries. However, MACSF can maintain in-vitro rat basilar arteries in good physiological activity and normal expression of contractile 5-HT and ET receptors.

KEYWORDS:

• Subarachnoid haemorrhage
• artificial cerebrospinal fluid
• magnesium
• contractile receptors
• ET-1
• S6c
• 5-HT

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under Grant NO. 81271227 and the National Key Technology R&D Program of China under Grant NO. 2014BAI04B05.

Notes on contributors

Ya-Wen Cheng

Ya-Wen Cheng is now a MD student under the supervision of Prof. Guo-Gang Luo in Xi’an Jiaotong University. She used to be a visiting scholar in the Department of Neurosurgery, University of Texas Health Science Center at Houston. Her research interest is subarachnoid haemorrhage and cerebral vasospasm.

Yi-Chen Guo

Yi-Chen Guo is now a PhD student of Neurology under the supervision of Prof. Guo-Gang Luo in Xi’an Jiaotong University. She is now a visiting scholar in the Department of Neurosurgery, University of Texas Health Science Center at Houston. Her research interests include cerebrovascular disease and migraine.

Guo-Liang Li

Guo-Liang Li is currently a doctor in the First Affiliated Hospital of Xi’an Jiaotong University. He has obtained his doctor’s degree of Cardiovascular. His research interests include arrhythmia and coronary heart diseases.

Yong-Ning Deng

Yong-Ning Deng is a doctor in the First Affiliated Hospital of Xi’an Jiaotong University and now a visiting scholar in University of California at Los Angeles. She got her doctor’s degree of Neurology from Xi’an Jiaotong University. Her interest is cerebrovascular disease and Alzheimer disease.

Wen-Juan Li

Wen-Juan Li is currently a doctor in the Department of Neurology in the Second Affiliated Hospital of Lanzhou University. She got her MD degree from Xi’an Jiaotong University under the supervision of Prof. Guo-Gang Luo. Her interest is subarachnoid haemorrhage and cerebrovascular diseases.

Gao-Feng Xu

Gao-Feng Xu is now a doctor in the Department of Neurosurgery in the First Affiliated Hospital of Xi’an Jiaotong University. He is an associate professor with abundant experience in the treatment of aneurysmal SAH.

Zhong Deng

Zhong Deng is a MD student in Xi’an Jiaotong University and he got his master’s degree of Neurosurgery in 2015. He is now a visiting scholar in MD Anderson Cancer Center in Houston from December 2017. His research interest is intracranial tumours.

Yong-Xiao Cao

Yong-Xiao Cao is a professor of Pharmacology in Xi’an Jiaotong University and has been a visiting scholar in Lund University in Sweden and Glostrup Hospital in Denmark. His research is centred on vascular pharmacology.

Guo-Gang Luo

Guo-Gang Luo is an experienced professor in the First Affiliated Hospital of Xi’an Jiaotong University and is currently the deputy director of the Department of Neurology. He has been a visiting scholar in Lund University in Sweden. He is now heading a research group which focuses on cerebrovascular disease and migraine.