Arterial baroreflex control of muscle blood flow at the onset of voluntary locomotion in mice
Arterial baroreflex control of muscle blood flow at the onset of voluntary locomotion in mice
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DOI：
10.1113/jphysiol.2003.047530
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发表时间：
2003-11-15
影响因子：
5.5
通讯作者：
Nose, H
中科院分区：
文献类型：
--
作者：
Masuki, S;Nose, H
为了评价动脉压力感受性反射控制在肌肉血流量(MBF)和自主运动中的作用，在自由活动小鼠(CNT)前和阻断动脉压力感受性反射的传入或传出通路、颈动脉窦去神经(CSD)或腹腔注射酚妥拉明(BLK)后，分别测定了平均动脉压(MAP)、MBF和肌电(EMG)。通过置入股动脉导管测量平均动脉压。用针式激光多普勒血流计测量MBF，并用边缘频率为0.1 Hz的低通滤波器记录MBF。根据后肢肌电记录判断运动频率和持续时间。这些探头在测量前至少2天被植入。各组大鼠肌肉血管电导(MVC=mBF/MAP)在运动开始后1 S内开始升高，但在S开始运动的前9天，CSD和BLK的增加速度明显高于CNT(P<；0.001)。CSD和BLK组MAP均显著低于基线水平，且与前9位S平均动脉压升高高度相关(R2=0.842，P<；0.001)，而CNT组MAP在开始运动后显著升高8 S。虽然在自由运动状态下60分钟的总运动周期在CNT和CSD之间没有显著差异(P>；0。1)、短时0.1min~0.4min的运动频率，CSD组高于CNT组(P<；0.001)，且与各运动时相伴的MAP降低高度相关(R2=0.883，P<；0.01)。这些结果表明，动脉压力感受器反射抑制收缩肌肉的血管扩张，以维持自主运动开始时的MAP，并对小鼠继续给定的运动时间是必要的。
To assess the role of arterial baroreflex control in muscle blood flow (MBF) and voluntary locomotion, mean arterial pressure (MAP), MBF, and electromyograms (EMGs) were measured in freely moving mice before (CNT) and after blocking the afferent or efferent pathway of arterial baroreflexes, carotid sinus denervation (CSD), or intraperitoneal administration of phentolamine (BLK), respectively. MAP was measured through a catheter placed in the femoral artery. MBF was measured with a needle-type laser-Doppler flowmeter and recorded through a low-pass filter with an edge frequency of 0.1 Hz. The frequency and duration of locomotion were judged from EMG recordings in the hindlimb. These probes were implanted at least 2 days before the measurements. Muscle vascular conductance (MVC = MBF/MAP) in all groups started to rise within 1 s after the onset of locomotion, but the increasing rate in CSD and BLK was significantly higher than in CNT for the first 9 s (P < 0.001). MAP in CSD and BLK significantly decreased below the baseline within I s and this was highly correlated with the increase in MVC for the first 9 s (R-2 = 0.842, P < 0.001), whereas MAP in CNT increased significantly 8 s after the onset of locomotion. Although the total period of movement in a free-moving state for 60 min was not significantly different between CNT and CSD (P > 0. 1), the frequency of movement with a short duration of 0.1-0.4 min was higher in CSD than in CNT (P < 0.001), which was highly correlated with the reduction in MAP accompanying each period of movement (R-2 = 0.883, P < 0.01). These results suggest that arterial baroreflexes suppress vasodilatation in contracting muscle to maintain MAP at the onset of voluntary locomotion, and are necessary to continue a given duration of locomotion in mice.