Journal of Hebei Medical University ›› 2024, Vol. 45 ›› Issue (10): 1120-1128.doi: 10.3969/j.issn.1007-3205.2024.10.001

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Effect of chronic intermittent hypobaric hypoxia on L-type Ca2+ channels in cardiomyocytes of developing rats

  

  1. 1.Department of Medical Aesthetics, the Third Hospital of Shijiazhuang City, Hebei Province, 
    Shijiazhuang 050051, China; 2.Department of Physiology, School of Basic Medical Sciences, 
    Hebei Medical University, Shijiazhuang 050017, China; 3.Department of Ophthalmology, 
    Hebei General Hospital, Shijiazhuang 050057, China; 4.Department of Health 
    Education, Centre for Disease Control and Prevention of Kaiping District, 
    Hebei Province, Tangshan 063022, China

  • Online:2024-10-25 Published:2024-10-15

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Abstract: Objective To investigate the effects of chronic intermittent hypobaric hypoxia (CIHH) on L-type calcium current (ICaL) in developing rats. 
Methods Newborn male SD rats were randomly divided into 28-day CIHH intervention group (CIHH28), 42-day CIHH intervention group (CIHH42), 28-day control group (CON28) and 42-day control group (CON42). The CIHH intervention group underwent exposure to hypobaric hypoxia at an altitude of 3 000 meters for a duration of 28 days and 42 days respectively, with each session lasting 5 h per day. These conditions were characterized by a partial oxygen pressure (PO2) of 108.8 mmHg （1 mmHg=0.133 kPa） and a barometric pressure (PB) of 525 mmHg. The whole-cell patch clamp technique was employed to record the ICaL in ventricular myocytes. 
Results No significant differences was observed in the peak current or the current-voltage (I-V) relationship curve of ICaLin cardiomyocytes between the CON group and CIHH group (P＞0.05). However, during simulated ischemia/reperfusion (I/R), the peak ICaL was observed to be decreased, accompanied by an upward shift in the I-V relationship curve(P＜0.05).But the change of ICaL in cardiomyocytes was significantly smaller in CIHH group than in CON group (P＜0.05). The steady-state activation and inactivation curves of ICaL in the CIHH group showed no significant changes before and after I/R (P＞0.05). However, during the process of I/R, the steady-state inactivation curve for ICaL underwent a shift towards the left in both CON28 and CON42 groups (P＜0.05), whereas no such shift was observed in cardiomyocytes of CIHH28 and CIHH42 groups (P＞0.05). 
Conclusion CIHH can attenuate the effect of I/R injury on ICaL in ventricular myocytes of developing rat. 


Key words: chronic intermittent hypobaric hypoxia, L-type calcium current, cardiomyocytes