Ninomiya I, Matsukawa K, Honda T, Nishiura N, Nabuchi A
Department of Cardiac Physiology, National Cardiovascular Center, Osaka, Japan.
Jpn J Physiol. 1988;38(4):491-506. doi: 10.2170/jjphysiol.38.491.
The effects of baroceptor reflex on mean cardiac (MCSNA) and renal sympathetic nerve activity (MRNA) were analyzed before and after atropinized (0.1 mg/kg, i.v.) states in conscious cats at rest. Resting values of MCSNA, MRNA, mean aortic pressure (MAP), and heart rate (HR) were 85 +/- 6 imps/s, 76 +/- 11 imps/s, 100 +/- 4 mmHg, and 164 +/- 10 beats/min, respectively. Both MCSNA and MRNA changed almost inversely to changes in the absolute MAP in the range of 90-140 mmHg. Within this pressure range the gain of baroceptor-sympathetic system to the heart and kidney was 2.31 and 1.84, respectively. MCSNA as well as MRNA was reduced to the noise level at the MAP of 142 and 150 mmHg, respectively. With atropine, MCSNA and MRNA were inhibited centrally whereas HR increased to 192 beats/min. The increase in MAP caused by norepinephrine (2.1 micrograms/kg, i.v.) was enhanced to 75 +/- 7 mmHg by atropine from 31 +/- 4 mmHg in control. The piecewise linear MAP-MCSNA and MAP-MRNA relationships changed to a remarkable clockwise hysteresis loop. During the rising MAP period, the gain of the baroceptor-sympathetic system decreased to 0.91 and 0.97 in MCSNA and MRNA, respectively. During the returning MAP period, a delayed activation in MCSNA and MRNA occurred centrally. We conclude that the baroceptor reflex effect on MCSNA is larger than those on MRNA, and that the baroceptor control of MCSNA and MRNA is modified centrally by atropine in the awake cat at rest.
在静息状态下，对清醒猫进行阿托品化（静脉注射0.1mg/kg）前后，分析了压力感受器反射对平均心脏交感神经活动（MCSNA）和肾交感神经活动（MRNA）的影响。MCSNA、MRNA、平均主动脉压（MAP）和心率（HR）的静息值分别为85±6次/秒、76±11次/秒、100±4mmHg和164±10次/分钟。在90 - 140mmHg范围内，MCSNA和MRNA的变化几乎与绝对MAP的变化呈反比。在此压力范围内，压力感受器 - 交感神经系统对心脏和肾脏的增益分别为2.31和1.84。MCSNA和MRNA分别在MAP为142mmHg和150mmHg时降至噪声水平。使用阿托品后，MCSNA和MRNA在中枢受到抑制，而HR增加到192次/分钟。去甲肾上腺素（静脉注射2.1μg/kg）引起的MAP升高在对照中为31±4mmHg，经阿托品作用后升高至75±7mmHg。分段线性的MAP - MCSNA和MAP - MRNA关系转变为明显的顺时针滞后环。在MAP上升期，压力感受器 - 交感神经系统对MCSNA和MRNA的增益分别降至0.91和0.97。在MAP恢复期，MCSNA和MRNA在中枢出现延迟激活。我们得出结论，压力感受器反射对MCSNA的影响大于对MRNA的影响，并且在静息清醒猫中，阿托品在中枢改变了压力感受器对MCSNA和MRNA的控制。
