Summary
In order to characterize different sub-zones in the palisade zone of the rat median eminence, quantitative ultrastructural parameters were applied to brains fixed in aldehyde-osmium tetroxide. The palisade zone has been subdivided in 4 successive sub-zones. Increasing numbers of granular vesicles (GV), especially those smaller than 110 nm, are observed from dorsal to ventral sub-zones. There also are more GV per unit area of nervous tissue in the perivascular than in the more dorsal sub-zones. The individual nerve profiles exhibit a larger size in the perivascular layer than in the more dorsal areas, whereas the number and size of nerve profiles devoid of vesicles diminish from dorsal to ventral. As a consequence more GV occur in the perivascular nerve profiles. In the GV containing nerve profiles the concentration of GV is, however, constant in the different sub-zones. A fluctuating size of the preterminal and terminal parts of the nerve fibres is suggested.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Akmayev, I. G., Réthelyi, M., Majorossy, K.: Changes induced by adrenalectomy in nerve endings of the hypothalamic median eminence (zona palisadica) in the albino rat. Acta biol. Acad. Sci. hung. 18, 187–200 (1967).
Barry, J.: Etude en fluorescence U.V. des monoamines des axes hypothalamo-préhypophysaires chez divers rongeurs. In: Neuroendocrinologie (eds. J. Benoit, C. Kordon), p. 59–72. Paris: C.N.R.S. 1970.
Björklund, A., Falck, B., Hromek, F., Owman, C., West, K. A.: Identification and terminal distribution of the tubero-hypophyseal monoamine fibre systems in the rat by means of stereotaxic and microspectrofluorimetric techniques. Brain Res. 17, 1–23 (1970).
Daikoku, S., Kotsu, T., Hashimoto, M.: Electron microscopic observations on the development of the median eminence in perinatal rats. Z. Anat. Entwickl.-Gesch. 134, 311–327 (1971)
Doerr-Schott, J., Follenius, E.: Identification et localisation des fibres aminergiques dans l'éminence médiane de la grenouille verte (Rana esculenta L.) par autoradiographie au microscope électronique. Z. Zellforsch. 111, 427–436 (1970).
Douglas, W. W., Nagasawa, J., Schulz, R.: Electron microscopic studies on the mechanism of secretion of posterior pituitary hormones and significance of microvesicles (“synaptic vesicles”): evidence of secretion by exocytosis and formation of microvesicles as a by-product of this process. In: Subcellular organization and function in endocrine tissue (eds. H. Heller, K. Lederis). Cambridge: University Press. Mem. Soc. Endocrinol. 19, 353–378 (1971).
Fuxe, K., Hökfelt, T.: Further evidence for the existence of tubero-infundibular dopamine neurons. Acta physiol. scand. 66, 245–246 (1966).
Fuxe, K., Hökfelt, T.: Catecholamines in the hypothalmus and the pituitary gland. In: Frontiers in neuroendocrinology (eds. W. F. Ganong, L. Martini), p. 47–96. New York: Oxford University Press 1969.
Hökfelt, T.: The possible ultrastructural identification of tubero-infundibular dopamine-containing nerve endings in the median eminence of the rat. Brain Res. 5, 121–123 (1967).
Hökfelt, T.: In vitro studies on central and peripheral monoamine neurons at the ultrastructural level. Z. Zellforsch. 91, 1–74 (1968).
Hökfelt, T., Fuxe, K.: On the morphology and the neuroendocrine role of the hypothalamic catecholamine neurons. In: Brain-endocrine interaction. Median eminence: Structure and function. Int. Symp. Munich (eds. K. M. Knigge, D. E. Scott, A. Weindl), p. 181–223. Basel: Karger 1972.
Kobayashi, T., Kobayashi, T., Yamamoto, K., Kaibara, M.: Electron microscopic observation on the hypothalamo-hypophyseal system in the rat. II. Ultrafine structure of the median eminence and of the nerve cells of the arcuate nucleus. Endocr. jap. 14, 158–177 (1967).
Kobayashi, T., Kobayashi, T., Yamamoto, K., Kaibara, M., Ajika, K.: Electron microscopic observation on the hypothalamo-hypophyseal system in rats. IV. Ultrafine structure of the developing median eminence. Endocr. jap. 15, 337–363 (1968).
Lichtensteiger, W., Langemann, H.: Uptake of exogenous catecholamines by monoamine-containing neurons of the central nervous system: uptake of catecholamines by arcuato-infundibular neurons. J. Pharmacol. exp. Ther. 151, 400–408 (1966).
Martinez, P.: The structure of the pituitary stalk and the innervation of the neurohypophysis in the cat. Diss. Leiden 1960.
Matsui, T.: Fine structure of the median eminence of the rat. J. Fac. Sci. Tokyo, sec. IV, 11, 71–96 (1966).
Monroe, B. G., Newman, B. L., Schapiro, S.: Ultrastructure of the median eminence of neonatal and adult rats. In: Brain-endocrine interaction. Median eminence: Structure and function. Int. Symp. Munich (eds. K. M. Knigge, D. E. Scott, A. Weindl), p. 7–26. Basel: Karger 1972.
Pellegrino de Iraldi, A., Etcheverry, G. J.: Ultrastructural changes in the nerve endings of the median eminence after nialamide-DOPA administration. Brain Res. 6, 614–618 (1967).
Raisman, G.: A second look at the parvicellular neurosecretory system. In: Brain-endocrine interaction. Median eminence: Structure and function. Int. Symp. Munich (eds. K. M. Knigge, D. E. Scott, A. Weindl), p. 109–118. Basel: Karger 1972.
Réthelyi, M., Halász, B.: Origin of the nerve endings in the surface zone of the median eminence of the rat hypothalamus. Exp. Brain Res. 11, 145–158 (1970).
Rinne, U. K.: Ultrastructure of the median eminence of the rat. Z. Zellforsch. 74, 98–122 (1966).
Rinne, U. K.: Experimental electron microscopic studies on the neurovascular link between the hypothalamus and anterior pituitary. In: Aspects of neuroendocrinology (eds. W. Bargmann, B. Scharrer), p. 220–228. Berlin-Heidelberg-New York: Springer 1970.
Rinne, U. K.: Effect of adrenalectomy on the ultrastructure and catecholamine fluorescence of the nerve endings in the median eminence of the rat. In: Brain-endocrine interaction. Median eminence: Structure and function. Int. Symp. Munich (eds. K. M. Knigge, D. E. Scott, A. Weindl), p. 164–170. Basel: Karger 1972.
Sano, Y., Odake, G., Taketomo, S.: Fluorescence microscopic and electron microscopic observations on the tuberohypophyseal tract. Neuroendocrinology 2, 30–42 (1967).
Smith, G. C., Simpson, R. W.: Monoamine fluorescence in the median eminence of foetal, neonatal and adult rats. Z. Zellforsch. 104, 541–556 (1970).
Stoeckart, R., Jansen, H. G., Kreike, A. J.: Ultrastructural evidence for exocytosis in the median eminence of the rat. Z. Zellforsch. 131, 99–107 (1972).
Szentágothai, J., Flerkó, B., Mess, B., Halász, B.: Hypothalamic control of the anterior pituitary. Budapest: Akadémiai Kiadó 1972.
Weibel, E. R.: Stereological principles for morphometry in electron microscopic cytology. Int. Rev. Cytol. 26, 235–302 (1969).
Zambrano, D.: The arcuate complex of the female rat during the sexual cycle. An electron microscopic study. Z. Zellforsch. 93, 560–570 (1969).
Zambrano, D., de Robertis, E.: The effect of castration upon the ultrastructure of the rat hypothalamus. II. Arcuate nucleus and outer zone of the median eminence. Z. Zellforsch. 87, 409–421 (1968).
Author information
Authors and Affiliations
Additional information
We are indebted to Mrs. R. M. Y. Hartsteen for technical assistance. The constructive criticism of Prof. J. Moll is acknowledged, as well as the photographic assistance of Miss P. C. Delfos.
Rights and permissions
About this article
Cite this article
Stoeckart, R., Jansen, H.G. & Kreike, A.J. Quantitative data on the fine structural organization of the palisade zone of the median eminence. Z.Zellforsch 136, 111–120 (1973). https://doi.org/10.1007/BF00307683
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00307683