Sasaki H, Otake K, Mannen H, Ezure K, Manabe M
Department of Anatomy, Faculty of Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Japan.
J Comp Neurol. 1989 Apr 8;282(2):157-68. doi: 10.1002/cne.902820202.
The present study examined, in Nembutal-anesthetized and artificially ventilated cats, the morphologic properties of the inspiratory neurons of the ventral respiratory group (VRG). Horseradish peroxidase (HRP) was injected into 21 augmenting inspiratory or late inspiratory neurons with peak firing rates in the late inspiratory phase. The majority of the stained neurons were antidromically activated by stimulation of the cervical cord. Thirteen somata, located within or around the nucleus ambiguus (AMB), between 100 microns caudally and 2,000 microns rostrally to the obex, were stained. In ten cases, the stem axons issuing from the cells of origin coursed medially to cross the midline without giving off any axonal collaterals. Three neurons gave rise to axonal collaterals on the ipsilateral side, distributing boutons in the medullary reticular formation, in the vicinity of the AMB, hypoglossal nucleus, solitary tract, and dorsal motor nucleus of the vagus. In eight neurons, only the axons were labeled; in four of these, which were antidromically activated from the spinal cord, the stem axons crossed the midline 2,000-3,000 microns rostral to the obex and descended in the reticular formation around the AMB down to the cervical cord. They issued several axonal collaterals, distributing terminal boutons at the level of the caudal end of the retrofacial nucleus and about 1,000 microns rostral and caudal from the obex. Terminals were found mainly in and around the AMB, and a few were found in the vicinity of the dorsal motor nucleus of the vagus. The remaining four nonactivated axons distributed their terminal boutons widely in the reticular formation around the AMB. Thus, the augmenting inspiratory neurons of the VRG were shown to project not only to the spinal cord, but also to the VRG, hypoglossal nucleus, and dorsal motor nucleus of the vagus.
本研究在戊巴比妥麻醉并人工通气的猫身上，检查了腹侧呼吸组（VRG）吸气神经元的形态学特性。将辣根过氧化物酶（HRP）注入21个在吸气后期具有峰值放电率的增强型吸气或晚期吸气神经元。大多数染色神经元通过刺激颈髓被逆向激活。13个胞体位于疑核（AMB）内或其周围，在闩尾侧100微米至吻侧2000微米之间，被染色。在10例中，起源细胞发出的轴突干向内侧走行以穿过中线，未发出任何轴突侧支。3个神经元在同侧发出轴突侧支，在延髓网状结构、AMB附近、舌下神经核、孤束和迷走神经背运动核周围分布终扣。在8个神经元中，只有轴突被标记；其中4个从脊髓被逆向激活，轴突干在闩吻侧2000 - 3000微米处穿过中线，并在AMB周围的网状结构中向下延伸至颈髓。它们发出几条轴突侧支，在面后核尾端水平以及闩吻侧和尾侧约1000微米处分布终扣。终末主要见于AMB内及其周围，少数见于迷走神经背运动核附近。其余4个未被激活的轴突在AMB周围的网状结构中广泛分布终扣。因此，VRG的增强型吸气神经元不仅投射到脊髓，还投射到VRG、舌下神经核和迷走神经背运动核。
