Aim To explore the role of gap junctions on the regulation of vascular tension and the repair of vascular injury. Methods Vascular rings from rat carotid artery were made and used to compare to the changes of vascular response to norepinephrine (NE) or acetylcholine (Ach) with or without 18α-GA. The model of vascular injury was established with rat carotid balloon injury. And animals were administrated with intraperitoneal injections of carbenoxolone (3 mg/(kg·d)) in carbenoxolone group or saline (2 mL/d) in control group for 2 weeks after carotid balloon injury. After 2 weeks, HE staining and DAPI-Evens blue double staining were applied to evaluate the neointimal formation of targeted vessels. And cell immunofluorescence staining and Western blot were used to detect connexin 43 (Cx43) expression on targeted vessels. Results 18α-GA alone didn’t cause significant response of vascular rings to systole or diastole. In control group, NE or Ach could induce vascular rings to contract or relax, but 18α-GA could inhibit the contraction or relaxation of vascular rings triggered by NE or Ach (NE:0.60±0.03 vs. 0.21±0.04; Ach:0.15±0.01 vs. 0.62±0.03; P＜0.05). 2 weeks after carotid balloon injury, carbenoxolone could significantly reduce the neointimal formation and the stenosis of blood vessel lumen. The number of neointimal nuclei in the carbenoxolone group was significantly lower than that in the control group (89±28 vs. 236±15, n＝5, P＜0.01). Immunofluorescence staining showed that Cx43 was abundant in neointima. Western blot results also suggested that the expression of Cx43 in the carbenoxolone group was significantly lower than that in the control group (0.93±0.06 vs. 0.38±0.11, n＝3, P＜0.01). Conclusions Gap junctions participate in maintaining and regulating vascular tension under the physiological condition, and promote the neointimal formation after vascular injury under the pathological condition. Hence, gap junctions play a key role on the development and progression of vascular injury diseases.