Interactions of the peripheral and central inputs on the swallowing initiation

吞咽是维持生命所必需的基本功能。它的运动行为是由位于延髓的吞咽中枢控制的。这个中心在吞咽过程中产生高度协调的运动序列。它主要由两部分组成；一部分由髓质尾侧的细胞组成，接收外周输入；另一组由位于髓质腹侧区的运动核组成，其中包含若干颅神经，包括三叉神经(V)、面神经（VII）、舌咽神经（IX）、迷走神经(X)和舌下神经（XII），它们控制吞咽相关肌肉。我们也知道这个机制接收来自其他区域的输入，如呼吸中枢、咀嚼中枢和髓上区。上述区域之间的相互作用尤其不清楚。本研究的目的是利用自由行为的家兔来阐明这些区域之间的相互作用。结论：吞咽中枢、咀嚼中枢与髓上区之间可能存在较高级的协调性。总结了它们之间的一种假设的相互作用。1)吞咽中心不受咀嚼中心的填充控制，但吞咽中心可能控制或同步燕子的产生。2)相反，吞咽中枢可能重置咀嚼节奏，使咀嚼运动减慢，下一个咀嚼周期在O_2期开始。3)髓上区可能向吞咽中枢发送强直性兴奋输入，维持吞咽中枢的兴奋性。4)自然静息和电SLN刺激对燕子的诱导是相同的。

Swallowing is a primitive function necessary for the life support. Its motor behavior is controlled by a swallowing center, which is located in the medulla oblongata. This center generates highly coordinated motor sequence during swallowing. It is mainly composed of two parts; on e part consists of cells in the caudal region of the medulla and receives peripheral inputs; the other consists of motor nuclei in the ventral region of the medulla containing several cranial nerves, including the trigeminal (V), facial (VII), glossopharyngeal(IX), vagal(X) and hypoglossal(XII) nerves, operating the swallowing related muscies. It is also known that this mechanism receives inputs form other regions, such as respiratory center, chewing center and supramedullary regions. Interactions between the above mentioned regions are particularly unclear. The objective of the present study was to elucidate the interaction between these regions using freely behaving rabbits.It is concluded that advanced coordination may exist between the swallowing center, chewing center and supramedullary region. A hypothetic interaction between them is summarized.1)The swallowing center could not be under the fill control of the chewing center, but the generation of swallows might be controlled or synchronized by the chewing center.2) Conversely, the swallowing center might reset the chewing rhythm so that the chewing movement was slowed and the next chewing cycle began in the O_2 phase.3) The supramedullary region might send a tonic excitatory input to the swallowing center and maintain its excitability.4) The swallows elicited both by natural stlmull and the electrical SLN stimuli were concluded to be identical to each other.