title: [Short-term simulated weightlessness enhances response of L-type calcium channel to angiotensin II in cerebral vascular smooth muscle cells in rats].
abstract: Some studies suggest that the calcium channels and rennin-angiotensin system (RAS) play pivotal roles in the region-specific vascular adaptation due to simulated weightlessness. This study was designed to clarify if angiotensin II (Ang II) was involved in the adaptational change of the L-type calcium channel (Ca(L)) in the cerebral arterial vascular smooth muscle cells (VSMCs) under simulated weightlessness. Tail suspension (SUS) for 3 d was used to simulate immediate early cardiovascular changes to weightlessness. Then VSMCs in cerebral basilar artery were enzymatically isolated using papain, and Ca(L) current (barium instead of calcium as current carrier) in VSMCs was measured by whole-cell patch-clamp techniques. The results showed that 3-day simulated weightlessness significantly increased current density of Ca(L). However, I-V relationships of normalized peak current densities and steady-state activation curves of Ca(L) were not affected by simulated weightlessness. Although Ang II significantly increased current densities of Ca(L) in both SUS and control rats, the increase of Ca(L) current density in SUS rats was much more than that in control rats. These results suggest that 3-day simulated weightlessness induces the adaptational change of Ca(L) in cerebral VSMCs including increased response to Ang II, indicating that Ang II may play an important role in the adaptational change of cerebral arteries under microgravity.
authors.affiliation: Departments of Clinical Aerospace Medicine and Aerospace Physiology, Key Laboratory of Aerospace Medicine of Ministry of Education, the Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Jun-hui
authors.initials: JH
authors.lastname: Xue
authors.forename: Xiao-cheng
authors.initials: XC
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Gao
authors.forename: Yun-gang
authors.initials: YG
authors.lastname: Bai
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Zuo-ming
authors.initials: ZM
authors.lastname: Zhang
mesh_terms: D000222:Adaptation, Physiological; D000804:Angiotensin II / Q000502:physiology*; D000818:Animals; D020746:Calcium Channels, L-Type / Q000502:physiology*; D002536:Cerebral Arteries / Q000166:cytology* / Q000502:physiology; D019417:Hindlimb Suspension; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D018474:Weightlessness Simulation
chemical_list: D020746:Calcium Channels, L-Type; D000804:Angiotensin II