Baroreflex increases correlation and coherence of muscle sympathetic nerve activity (SNA) with renal and cardiac SNAs
Baroreflex increases correlation and coherence of muscle sympathetic nerve activity (SNA) with renal and cardiac SNAs
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DOI：
10.2170/physiolsci.rp009006
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发表时间：
2006-10-01
影响因子：
2.3
通讯作者：
Sugimachi, Masaru
中科院分区：
文献类型：
--
作者：
Kamiya, Atsunori;Kawada, Tbru;Sugimachi, Masaru
尽管积累的数据，肌肉交感神经活动（SNA）测量人体显微神经造影术，肌肉SNA的神经放电是否相关，并与其他SNA控制内脏器官的一致性仍然不清楚。此外，SNA的压力反射控制如何影响这些SNA之间的关系仍然未知。在氨基甲酸乙酯和α-氯醛糖麻醉，迷走神经切断，和arteric-denervated兔，我们记录肌肉SNA从胫神经显微神经摄影术，同时记录肾脏和心脏SNA。在分离颈动脉窦后，我们通过将分离的颈动脉窦内压（CSP）与体循环动脉压（CLOSE）相匹配来产生压力反射闭环条件。我们还将CSP固定在工作压力（FIX）或广泛改变CSP（WIDE：工作压力40 mmHg）。在这些条件下，我们计算了肌肉SNA与肾脏或心脏SNA之间相关性的时域和频域测量。在CLOSE时，以1 Hz重新采样的肌肉SNA与最佳延迟时的肾脏SNA（r（2）= 0.71 +/- 0.04，延迟= 0.10 +/- 0.004 s）和心脏SNA（r（2）= 0.58 +/- 0.03，延迟= 0.13 +/- 0.004 s）相关。此外，在自谱峰值频率处，CLOSE处的肌肉SNA与肾脏和心脏SNA强相干（相干性> 0.8），而在其余频率处弱相干（0.4-0.5）。从FIX到CLOSE，再到WIDE，CSP变化幅度的增加导致非峰值频率处的相关性和相干性函数相应增加，峰值频率处的相干性函数保持较高（> 0.8）。总之，在闭环压力反射条件下，肌肉SNA与肾脏和心脏SNA相关并大致一致。动脉压力感受性反射能够通过调节SNA自谱非峰频率处的SNA来有效地抑制这些SNA的神经放电。
Despite accumulating data of muscle sympathetic nerve activity (SNA) measured by human microneurography, whether neural discharges of muscle SNA correlates and coheres with those of other SNAs controlling visceral organs remains unclear. Further, how the baroreflex control of SNA affects the relations between these SNAs remains unknown. In urethane and alpha-chloralose anesthetized, vagotomized, and aortic-denervated rabbits, we recorded muscle SNA from the tibial nerve using microneurography and simultaneously recorded renal and cardiac SNAs. After isolating the carotid sinuses, we produced a baroreflex closed-loop condition by matching the isolated intracarotid sinus pressure (CSP) with systemic arterial pressure (CLOSE). We also fixed CSP at operating pressure (FIX) or altered CSP widely (WIDE: operating pressure 40 mmHg). Under these conditions, we calculated time-domain and frequency-domain measures of the correlation between muscle SNA and renal or cardiac SNAs. At CLOSE, muscle SNA resampled at 1 Hz correlated with both renal (r(2) = 0.71 +/- 0.04, delay = 0.10 +/- 0.004 s) and cardiac SNAs (r(2) = 0.58 +/- 0.03, delay = 0.13 +/- 0.004 s) at optimal delays. Moreover,muscle SNA at CLOSE strongly cohered with renal and cardiac SNAs(coherence > 0.8) at the autospectral peak frequencies, and weakly (0.4-0.5) at the remaining frequencies. Increasing the magnitude of CSP change from FIX to CLOSE and further to WIDE resulted in corresponding increases in correlation and coherence functions at nonpeak frequencies, and the coherence functions at peak frequencies remained high (> 0.8). In conclusion, muscle SNA correlates and coheres approximately with renal and cardiac SNAs under closed-loop baroreflex conditions. The arterial baroreflex is capable of potently homogenizing neural discharges of these SNAs by modulating SNA at the nonpeak frequencies of SNA autospectra.