Membrane potential properties in the smooth muscle cells of middle cerebral artery in stroke-prone spontaneously hypertensive rats / 中国组织工程研究

ABSTRACT

BACKGROUND: The small change of the membrane potential (Em) of vascular smooth muscle cells (VSMC) could result in significant alteration in tension, and the membrane depolarization was closely associated with the development of hypertension.OBJECTIVE: To study the resting Em of VSMC from the middle cerebral artery (MCA) of stroke-prone spontaneously hypertensive rats (SHRSP) and the reactivity of Em to KCl and norepinephrine (NE).DESIGN: An animal experiment of comparative analysis.SETTING: Institute of Materia Medica, Shandong Academy of Medical Sciences.MATERIALS: Eighteen male SHRSP and 26 male Wistar rats were used.METHODS: ① Rats in both groups were anesthetized with intraperitoneal injection of ethyl carbamate (1 g/kg), the brains were removed quickly, and the Em of VSMC was recorded by intracellular microelectrodes. ② The effects of different concentrations of KC1 (10, 20, 50 mmol/L) and NE (10-7,10-6, 10-5 mol/L) on the Em of VSMC were observed.MAIN OUTCOME MEASURES: ① Em of VSMC in both groups; ②Effects of different concentrations of KC1 and NE on the Em of VSMC.RESULTS: ① The Em was obviously lower in SHRSP than in the Wistar rats [(-48.2±3.1), (-64.4±4.3) mV]. ② Both KC1 (10, 20, 50 mmol/L)and NE (10-7, 10-6, 10-5 mol/L) could cause the depolarization of Em of MCA in a concentration-dependent manner. The reactivity to MCA of SHRSP was obviously increased as compared with the Wistar rats.CONCLUSION: The resting Em of VSMC from the MCA of SHRSP was lower, and the reactivity of VSMC to KCl and NE was significantly stronger than that of Wistar rats.