Fyffe R E, Light A R
Brain Res. 1984 May 23;300(2):201-9. doi: 10.1016/0006-8993(84)90831-x.
Ia synapses in laminae VI and IX of the cat's spinal cord were examined in the electron microscope following iontophoretic injection of horseradish peroxidase (HRP) into single, identified, Ia afferent fibers from gastrocnemius muscles. Ia boutons contacting motoneuron dendrites in lamina IX contained spherical synaptic vesicles and generally contacted only one postsynaptic profile. The Ia boutons were often postsynaptic to smaller P-type axonal terminals. Consequently Ia boutons may be classified as S-boutons with axo-axonic contacts.
在用离子电渗法将辣根过氧化物酶（HRP）注入来自腓肠肌的单个、已鉴定的Ia传入纤维后，对猫脊髓第VI和第IX层中的Ia突触进行了电子显微镜检查。与第IX层运动神经元树突接触的Ia终扣含有球形突触小泡，通常仅与一个突触后成分接触。Ia终扣常常是较小的P型轴突终末的突触后成分。因此，Ia终扣可归类为具有轴-轴突触联系的S型终扣。
