Robbins A, Sato Y
Department of Physiology, Tokyo Metropolitan Institute of Gerontology, Japan.
J Auton Nerv Syst. 1991 Apr;33(1):55-63. doi: 10.1016/0165-1838(91)90018-x.
These experiments examined cardiovascular responses to uterine horn distension in anesthetized rats. Changes in blood pressure and heart rate following distension of the uterine horn were compared in estrous and diestrous rats. In the estrous rats, there was a significant decrease in both heart rate and blood pressure following uterine horn pressure of 150 mmHg or greater. This depressor and bradycardia response did not reliably occur in the diestrous rats. To determine the afferent limb of this uterine-cardiovascular reflex, the pelvic and hypogastric nerves were cut consecutively and the effect of uterine horn distension was tested after each nerve cut. Following hypogastric, but not pelvic nerve transection, the cardiovascular responses to uterine horn distension were eliminated or severely attenuated. The importance of hypogastric afferent nerve fibers was further demonstrated by recording single unit activity in these fibers to uterine horn distension. The units responded with a pressure-dependent increase in firing rate, at uterine pressure levels of 50 mmHg and higher. To determine the efferent limb of the reflex, the cardiovascular responses were measured before and after vagus nerve transection. Elimination of this parasympathetic neural activity did not affect the inhibitory cardiovascular responses to uterine horn distension, suggesting that these fibers may not be responsible for the decrease in heart rate and blood pressure. Recordings of multi-unit activity from sympathetic efferent fibers in the renal nerve, a vasoconstrictor nerve, showed a decrease to uterine horn distension. A decrease in renal nerve efferent activity was observed at uterine horn pressures of 150 mmHg or greater and the time course of the renal nerve response paralleled the cardiovascular response.(ABSTRACT TRUNCATED AT 250 WORDS)
这些实验研究了麻醉大鼠对子宫角扩张的心血管反应。比较了动情期和动情间期大鼠子宫角扩张后血压和心率的变化。在动情期大鼠中，当子宫角压力达到150 mmHg或更高时，心率和血压均显著下降。这种降压和心动过缓反应在动情间期大鼠中并不可靠出现。为了确定这种子宫 - 心血管反射的传入支，依次切断盆腔神经和腹下神经，并在每次神经切断后测试子宫角扩张的效果。切断腹下神经而非盆腔神经后，对子宫角扩张的心血管反应消失或严重减弱。通过记录这些纤维对子宫角扩张的单单位活动，进一步证明了腹下传入神经纤维的重要性。在子宫压力达到50 mmHg及更高时，这些单位的放电频率随压力增加。为了确定反射的传出支，在切断迷走神经前后测量心血管反应。消除这种副交感神经活动并不影响对子宫角扩张的抑制性心血管反应，这表明这些纤维可能与心率和血压的下降无关。对肾神经（一种血管收缩神经）中交感传出纤维的多单位活动记录显示，对子宫角扩张有下降反应。在子宫角压力达到150 mmHg或更高时，观察到肾神经传出活动下降，且肾神经反应的时间进程与心血管反应平行。（摘要截短至250字）
