Relationship between TWIK-related acid-sensitive K+ channel-1 and TWIK-related acid-sensitive K+ channel-3 expression and the occurrence of central sleep apnea: experiment with rats

Abstract

To investigate the role of the TWIK-related acid-sensitive K(+) channel-1 (TASK-1) in the occurrence of sleep apnea. Brain and muscle electrodes were put on 27 SD rats to monitor the apneic episodes. Then the rats were killed with their brains taken out. Western blotting was used to examine the expression of TASK-1 as well as its family member TASK-3 in the brainstem. Another 32 rats were randomly divided into 3 groups: intermittent hypercapnic hypoxia (IHH) group (n = 14, undergoing IHH 2 hours a day for 14 days), continuous hypoxia (CH) group (n = 6, undergoing CH for 2 hours everyday for 14 days), and normal control group (n = 10). On the day 15 the rats were killed with venous blood samples collected to undergo blood routine examination and brainstem samples collected to undergo Western blotting to measure the expression of TASK-1 and TASK-3. The relationship between TASK-1 and TASK-3 expression and the occurrence of central sleep apnea was analyzed. In the normal rats the spontaneous apnea index (SPAI) was positively correlated with the protein expression of TASK-in the brainstem and the ratio of the TASK-1 protein expression to the TASK-3 protein expression (r = 0.547 and 0.406 respectively, both P < 0.05). However, the post-sign apnea index (PSAI) was not correlated with the TASK-1 protein expression (P = 0.986), and both the SPAI and PSAI were not correlated with the TASK-3 protein expression (P = 0.986 and 0.916 respectively). Only the SPAI in the non-rapid eye movement. stage was positively correlated with the TASK-1 protein expression and the ratio of TASK-1 protein expression to TASK-3 protein expression (r = 0.601, 0.523 respectively, both P < 0.01). The TASK-1 protein expression of the IHH group was significantly higher than those of the CH group and normal control group (P = 0.032 and 0.004 respectively). The TASK-3 protein expression of the IHH group was significantly higher than that of the CH group (P = 0.005). There were no significant differences in the TASK-1 protein expression and that of TASK-3 between the CH group and the normal control group (both P > 0.05). TASK-1 may play an important role in spontaneous sleep apnea.