Neuromuscular compartments and fiber-type regionalization in the human inferior pharyngeal constrictor muscle
Neuromuscular compartments and fiber-type regionalization in the human inferior pharyngeal constrictor muscle
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DOI：
10.1002/ar.10020
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发表时间：
2001-12-01
影响因子：
--
通讯作者：
Sanders, I
中科院分区：
文献类型：
--
作者：
Mu, LC;Sanders, I
下咽缩肌（IPC）在吞咽、呼吸和发声过程中发挥作用。IPC的最尾部被认为是功能性上食管括约肌（UES）的一部分。我们推测，人类IPC的尾纤维可能具有类似的酶组织化学特征的喉肌，UES的主要组成部分。在这项研究中，从尸体解剖获得的人IPC肌肉进行了研究，使用Sihler的染色检查神经支配模式，并使用肌原纤维ATP酶，NADH四唑还原酶（NADH-TR），琥珀酸脱氢酶（SDH）技术，以调查的分布和氧化能力的慢（I型）和快（II型）抽搐纤维在肌肉中。结果表明，人IPC至少由头侧和尾侧两个神经肌肉隔室（NMC）组成。每一个NMCs由来自迷走神经咽分支的单独神经分支支配。头侧NMC比尾侧NMC快（39% I型，61% II型）（70% I型，30% II型）。此外，在人IPC中确定了两个组织化学描绘的纤维层：以I型纤维为主的慢内层（SIL）（66%）和以II型纤维为主的快外层（FOL）（62%）（P < 0.01）。然而，这两个纤维层的尺寸和肌纤维类型的比例与NMC不同。具体而言，SIL与FOL的厚度之比在尾部NMC为2：1，在喙部NMC为1：2。在SIL中，I型纤维占84%的尾部NMC和69%和44%的吻侧NMC的下部和上部。FOL中II型纤维在尾侧NMC中占46%，在吻侧NMC的上部和下部分别占67%和74%（P < 0.01）。IPC的尾部NMC与喉阔肌的组织化学特征相同，因为它主要含有慢氧化纤维。总体而言，IPC中的尾部NMC和SIL具有较高的NADH-TR和SDH活性。然而，在I型和II型纤维中发现了不同的氧化酶活性模式。本研究为IPC内的尾部NMC参与功能性UES的概念提供了组织化学证据。此外，IPC中的两个组织化学定义的纤维层可能是人类在呼吸，吞咽和言语期间实现不同上气道功能的专门适应。Anat Rec 264：367-377，2001年。(C)2001 Wiley-Liss，Inc.
The inferior pharyngeal constrictor (IPC) muscle functions during swallowing, respiration, and vocalization. The most-caudal portion of the IPC is believed to be part of the functional upper esophageal sphincter (UES). We hypothesized that the caudal fibers of the human IPC may have enzyme-histochemical characteristics similar to those of the cricopharyngeus muscle, a major component of the UES. In this study, human IPC muscles obtained from autopsy were studied using Sihler's stain to examine innervation patterns, and using myofibrillar ATPase, NADH tetrazolium reductase (NADH-TR), and succinic dehydrogenase (SDH) techniques to investigate the distribution and oxidative capacity of the slow- (type I) and fast- (type II) twitch fibers in the muscle. The results showed that the human IPC consists of at least two neuromuscular compartments (NMCs): rostral and caudal. Each of the NMCs was innervated by a separate nerve branch derived from the pharyngeal branch of the vagus nerve. The rostral NMC is faster (39% type 1, 61% type II) than the caudal NMC (70% type I, 30% type II). In addition, two histochemically-delineated fiber layers were identified in the human IPC: a slow inner layer (SIL) with predominantly type I fibers (66%), and a fast outer layer (FOL) with predominantly type II fibers (62%) (P < 0.01). However, the dimensions of both fiber layers and proportions of the muscle fiber types varied with the NMCs. Specifically, the ratio of the thickness of the SIL to FOL was 2:1 for the caudal NMC and similar to1:2 for the rostral NMC, respectively. In the SIL the type I fibers accounted for 84% for the caudal NMC and 69% and 44% for the lower and upper portions of the rostral NMC. In contrast, the type II fibers in the FOL accounted for 46% for the caudal NMC and 67% and 74% for the lower and upper portions of the rostral NMC, respectively (P < 0.01). The caudal NMC of the IPC shared histochemical characteristics with the cricopharyngeus muscle, in that it contained predominantly slow oxidative fibers. Overall, the caudal NMC and the SIL in the IPC had high NADH-TR and SDH activities. However, different patterns of oxidative enzyme activity were identified in both type I and type II fibers. This study provided histochemical evidence for the concept that the caudal NMC within the IPC contributes to the functional UES. In addition, the two histochemically-defined fiber layers in the IPC may be a specialized adaptation in humans to enable different upper-airway functions during respiration, swallowing, and speech. Anat Rec 264:367-377, 2001. (C) 2001 Wiley-Liss, Inc.