Maxwell D J, Bannatyne B A, Fyffe R E, Brown A G
J Neurocytol. 1982 Aug;11(4):571-82. doi: 10.1007/BF01262425.
In acute electrophysiological experiments on anaesthetized cats, single identified hair follicle afferent fibres were injected with horseradish peroxidase (HRP). The HRP was injected from an intra-axonal microelectrode in the lumbosacral spinal cord. One to six hours after injection the animals were perfused and the tissue prepared for light and electron microscopy (EM). Axon collateral arborizations containing HRP reaction product were identified in thick sections under the light microscope and the same tissue then cut on the ultramicrotome for EM study. The terminal branches of the collaterals kept their myelin sheaths until they were 0.45-1.0 micron in diameter, just before they formed synaptic boutons. Synaptic boutons (1.0-4.0 microns in diameter) were usually of the en passant variety and made contact with dendrites. The contacts were asymmetrical (Type I) and contained round, clear synaptic vesicles of 35-60 nm diameter. Both the non-myelinated portion of the terminal axon and the synaptic boutons received axo-axonic contacts. These axo-axonic boutons contained clear (agranular) vesicles irregular in profile.
在对麻醉猫进行的急性电生理实验中，用辣根过氧化物酶（HRP）对单个已识别的毛囊传入纤维进行注射。HRP从腰骶脊髓的轴突内微电极注入。注射后1至6小时，对动物进行灌注，并制备用于光学显微镜和电子显微镜（EM）观察的组织。在光学显微镜下的厚切片中识别出含有HRP反应产物的轴突侧支分支，然后将同一组织在超薄切片机上切片用于EM研究。侧支的终末分支在形成突触小体之前，其髓鞘一直保留到直径为0.45 - 1.0微米。突触小体（直径1.0 - 4.0微米）通常为依傍型，并与树突形成接触。这些接触是不对称的（I型），包含直径为35 - 60纳米的圆形、清亮的突触小泡。终末轴突的无髓部分和突触小体都接受轴 - 轴突触接触。这些轴 - 轴突触小体含有轮廓不规则的清亮（无颗粒）小泡。
