家兔面神经后核内侧区在呼吸节律起源中的作用

ROLE OF THE MEDIAL REGION OF NUCLEUS RETROFACIALIS OF THE RABBIT IN THE GENERATION OF RESPIRATORY RHYTHM

从腹侧面暴露家兔延髓,脑内微量注射1%普鲁卡因阻滞面神经后核内侧区(mNRF),全部动物(n=20)一次注射(0.3—1.0μl)后即能可逆地消除呼吸节律。区域对照显示此区非常局限,范围约1.0×1.0×1.0mm。组织学检查表明为面神经后核内侧区。本文分析了 mNRF的呼吸相关神经元(RRNs)的放电形式。在 mNRF 有较多的呼气(E)神经元和呼气-吸气跨时相(E-IPS)神经元。在阻滞 mNRF 引起呼吸停止期间,观察到低位延髓背侧呼吸群(DRG)和腹侧呼吸群(VRG)尾端区 RRNs 放电的节律性消失,表现连续放电或停止放电。电刺激DRG,VRG 尾端区,只能诱发短串的膈神经放电,而不能产生节律性发放。说明这些区域的RRNs 无自动节律性活动的能力。结果表明,面神经后核内侧区与呼吸节律发生有关,它可能是呼吸节律发生器的一个重要的所在部位。

The medulla of rabbits were exposed from ventral surface.When 1% pro-caine(0.3—1.0μl)was injected bilaterally through a micropipette into the medialregion of nucleus retrofacialis(mNRF),the respiratory movement and phrenicrhythmical discharge could be reversibly abolished in all of 20 rabbits tested.Thearea related is very limited,about 1.0×1.0×1.0mm.Histological examination hasshown that the effective injected area is mNRF.Discharge patterns of the respira-tory-related neurons(RRNs)in mNRF of the rabbit were analyzed.The resultshowed that there were many E and E-I PS neurones in the mNRF.Blockade ofmNRF caused continuous firing of most inspiratory and expiratory neurons recordedin the VRG and DRG and abolishment of respiratory rhythm.The minority ofrespiratory neurons were inactivated during apnea.Stimulation of the caudalportion of VRG and DRG during apnea could evoke only a short cluster of phrenicdischarges instead of rhythmical firing,indicating that respiratory neurons locatedin these areas can not generate rhythmic activity themselves.The results suggest that an important area of the respiratory rhythm generatorsmay be located in the medial region of nucleus retrofacialis.