Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
Physiol Res. 2011;60(4):659-66. doi: 10.33549/physiolres.932102. Epub 2011 May 16.
Spontaneous and electrically-elicited motor activity was recorded by triple organ bath in rat segment-model preparation as display of excitation of local nerve networks and ascending or descending reflex pathways underlying contractile potency and functional coordination of colonic longitudinal and circular muscles. Spontaneous high-amplitude contractions, but not relaxations, appeared synchronously in both muscles. Electrical field stimulation applied to proximal or distal part of segments elicited both tetrodotoxin (0.1 microM)-sensitive local motor responses of the stimulated part and ascending or descending motor responses of the contralateral, nonstimulated part of the preparations. Contractions characterized the local response of longitudinal muscle. The circular muscle responded with relaxation followed by contraction. Synchronous ascending contractions and descending contraction of the longitudinal muscle and relaxation followed by contraction of the circular muscle were observed when the middle part of segments was stimulated, thus indicating that locally-induced nerve excitation propagated via intrinsic ascending or descending nerve pathways that could be synchronously coactivated by one and the same stimulus. The ascending motor responses were more pronounced and the motor responses of longitudinal muscle were expressed more than those of circular muscle suggesting an essential role of ascending reflex pathways and longitudinal muscle in the coordinated motor activity of colon.
在大鼠节段模型制备中，通过三器官浴槽记录自发和电诱发的运动活动，以显示局部神经网络的兴奋以及支配结肠纵肌和环肌收缩效能和功能协调性的上行或下行反射通路。两种肌肉均同步出现自发的高振幅收缩，但无松弛。在节段的近端或远端施加电场刺激，可诱发受刺激部分的河豚毒素（0.1µM）敏感的局部运动反应，以及对侧未受刺激部分的上行或下行运动反应。纵向肌的局部反应表现为收缩。环肌先松弛，然后收缩。当刺激节段的中部时，可观察到纵向肌的同步上行收缩和下行收缩以及环肌的松弛后收缩，这表明局部诱导的神经兴奋通过内在的上行或下行神经通路传播，这些通路可以被同一刺激同步协同激活。上行运动反应更为明显，纵向肌的运动反应比环肌的更为明显，这表明上行反射通路和纵向肌在结肠的协调运动活动中起重要作用。
