Abstract
The origin of the axon was studied in Golgi-Kopsch impregnated specimens prepared from the spinal cord and brain of adult rats. Five types of neurons were sampled: large ventral horn neurons, neurons in the intermediate zone and ventral horn of the spinal cord, antenna-type neurons in the spinal dorsal horn, neurons in the thalamus, and neurons in the hypothalamus. The axon originated from the perikaryon in 76% of the large ventral horn neurons and in 64% of the neurons in the thalamus. In contrast, the axon emerged from one of the dendrites in 75% of the neurons in the intermediate zone and the ventral horn of the spinal cord and in 68% of the neurons in the hypothalamus. In the case of the antenna-type neurons in the spinal dorsal horn, the axon often originated from one of the dendrites, but never from a dorsally oriented dendrite. The mean distance of the axon hillock of dendritic origin was the longest in the neurons in the intermediate zone and the ventral horn of the spinal cord. The size of the axon hillock was proportional to the size of the perikaryon. The impregnated portion of the axon was longest in the large ventral horn neurons.
Article PDF
Similar content being viewed by others
References
Bodoky, M., Réthelyi, M. (1977) Dendritic arborization and axon trajectory of neurons in the hypothalamic arcuate nucleus of the rat. Exp. Brain. Res. 28, 543–555.
Chen, X. Y., Wolpaw, J. R. (1994) Triceps surae motoneuron morphology in the rat: a quantitative light microscopic study. J. Comp. Neurol. 343, 143–157.
Colbert, C. M., Johnston, D. (1996) Axonal action-potential initiation and Na+ channel densities in the soma and axon initial segment of subicular pyramidal neurons. J. Neuroscience 16, 6676–6686.
Conradi, S. (1969) Observations on the ultrastructure of the axon hillock and initial segment of lumbosacral motoneurons in the cat. Acta Physiol. Scand. Suppl. 332, 65–84.
Domesick, V. B., Morest, D. K. (1977) Migration and differentiation of shepherd’s crook cells in the optic tectum of the chick embryo. Neuroscience 2, 477–491.
Majorossy, K., Réthelyi, M. (1968) Synaptic architecture in the medial geniculate body (ventral division). Exp. Brain. Res. 6, 306–323.
Maxwell, D. J., Réthelyi, M. (1987) Ultrastructure and synaptic connections of cutaneous afferent fibres in the spinal cord. TINS 10, 117–123, 1987.
Millhouse, O. E. A Golgi anatomy of the rodent hypothalamus. In: Morgane, P. J., Pankseep, J. (eds), Handbook of the Hypothalamus, Vol. I. Marcel Dekker, Inc., New York, pp. 221–265.
Morest, D. K. (1970) A study of neurogenesis in the forebrain of opossum pouch young. Z. Anat. Ent. Gesch. 130, 265–305.
Palay, S. L., Sotelo, C., Peters, A., Orkland, P. M. (1968) The axon hillock and the initial segment. J. Cell. Biol. 38, 193–201.
Ramon y Cajal, S. (1999) Texture of the Nervous System of Man and Vertebrates. Springer Verlag, Vienna.
Réthelyi, M. (1976) Central core in the spinal gray matter. Acta Morph. Acad. Sci. Hung. 24, 63–70.
Segev, I., London, M. (1999) A theoretical view of passive and active dendrites. In: Stuart, G., Spruston, N., Häusser, M., Dendrites. Oxford University Press, pp. 203–230.
Spruston, N., Stuart, G., Häusser, M. (1999) Dendritic integration. In: Stuart, G., Spruston, N., Häusser, M., Dendrites. Oxford University Press, pp. 231–270.
Szentágothai, J. (1964) Neuronal and synaptic arrangement in the substantia gelatinosa Rolandi. J. Comp. Neurol. 1222, 219–240.
Szentágothai, J. (1964) The parvicellular neurosecretory system. Progr. Brain Res. 5, 135–146.
Ulfhake, B., Kellerth, J. O. (1981) A quantitative light microscopic study of the dendrites of cat spinal alpha-motoneurons after intracellular staining with horseradish peroxidase. J. Comp. Neurol. 202, 571–583.
Author information
Authors and Affiliations
Corresponding author
Additional information
Dedicated to Professor József Hámori on the occasion of his 70th birthday.
Rights and permissions
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
About this article
Cite this article
Réthelyi, M. Position and Size of the Axon Hillock in Various Groups of Neurons. BIOLOGIA FUTURA 53, 153–165 (2002). https://doi.org/10.1556/ABiol.53.2002.1-2.15
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1556/ABiol.53.2002.1-2.15