Summary
The ciliary body of the cat was investigated by fluorescence histochemistry and electron microscopy in an attempt to clarify its sympathetic innervation. Subconjunctival doses of 5-hydroxydopamine (5-OHDA) or 6-hydroxydopamine (6-OHDA) were given to establish the precise location of the sympathetic nerve terminals. The distribution of noradrenergic fibers and terminals was shown by fluorescence histochemistry to be sparse in the trabecular meshwork and the anterior portion of the ciliary muscle, but dense in the subepithelial tissue. The small and large dense core vesicles which occur in many nerve endings of the subepithelial tissue adjacent to the pigmented epithelial layer increased in electron density following the administration of 5-OHDA. Many degenerating nerve endings were found in the same region of animals treated with 6-OHDA. In contrast, there were few noradrenergic terminals in the ciliary muscle except for a portion of the smooth muscle which was shown to be dually innervated. The noradrenergic fibers in the subepithelial region and the trabecular meshwork may play an important role in aqueous secretion and outflow.
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Cobb, J.L., Bennett, T.: An electron microscopic examination of the short term effects of 6-hydroxydopamine on the peripheral adrenergic nervous system. In: 6-Hydroxydopamine and catecholamine neurons, edit. by T. Malmfors and H. Thoenen, p. 33–45. Amsterdam-London: North-Holland 1971
Ehinger, B.: Adrenergic nerves to the eye and to related structures in man and in the Cynomolgus monkey. Invest. Ophthal. 5, 42–52 (1966a)
Ehinger, B.: Distribution of adrenergic nerves in the eye and some related structures in the cat. Acta physiol. scand. 66, 123–128 (1966b)
Ehinger, B.: Connections between adrenergic nerves and other tissue components in the eye. Acta physiol. scand. 67, 57–64 (1966c)
Ehinger, B.: Localization of ocular adrenergic nerves and barrier mechanisms in some mammals. Acta ophthal. (Kbh.) 44, 814–822 (1966d)
Ehinger, B.: A comparative study of the adrenergic nerves to the anterior eye segment of some primates. Z. Zellforsch. 116, 157–177 (1971)
Hökfelt, T., Jonsson, G.: Studies on reaction and binding of monoamine after fixation and processing for electron microscopy with special reference to fixation with potassium permanganate. Histochemie 16, 45–67 (1968)
Holland, M.G.: Treatment of glaucoma by chemical sympathectomy with 6-hydroxydopamine. Trans. Amer. Acad. Ophthal. Otolaryng. 76, 437–449 (1972)
Ibata, Y., Matsuura, T., Nojyo, Y., Inoue, T., Sano, Y.: The effect of 5- and 6-hydroxydopamine on the central monoaminergic neurons of the rat and cat: Fluorescence histochemistry and electron microscopy. Acta histochem. cytochem. 7, 126–139 (1974)
Inomata, H., Bill, A., Smelser, G.K.: Aqueous humor pathways through the trabecular meshwork and into Schlemm's canal in the Cynomolgus monkey (Macaca irus).: An electron microscopic study. Amer. J. Ophthal. 73, 760–789 (1972)
Kitazawa, Y., Nose, H., Horie, T.: Chemical sympathectomy with 6-hydroxydopamine in the treatment of primary open-angle glaucoma. Amer. J. Ophthal. 79, 98–103 (1975)
Laties, A.M., Jacobowitz, D.: A comparative study of the autonomic innervation of the eye in monkey, cat and rabbit. Anat. Rec. 156, 383–393 (1966)
Malmfors, T.: The adrenergic innervation of the eye as demonstrated by fluorescence microscopy. Acta physiol. scand. 65, 259–267 (1965)
Malmfors, T.: The effects of 6-hydroxydopamine on the adrenergic nerves as revealed by the fluorescence histochemical method. In: 6-Hydroxydopamine and catecholamine neurons, edit. by T. Malmfors and H. Thoenen, p. 47–58. Amsterdam-London: North-Holland 1971
Nishida, S., Trotter, F., Sears, M.L.: Innervation of the chamber angle of the guinea pig eye. Exp. Eye Res. 8, 143–146 (1969)
Nomura, T., Smelser, G.K.: The identification of adrenergic and cholingergic nerve endings in the trabecular meshwork. Invest. Ophthal. 13, 525–532 (1974)
Ochi, J.: A study of potassium permanganate fixation for electron microscopic detection of small granular vesicles in the sympathetic nervous system. Acta histochem. cytochem. 2, 13–18 (1969)
Richardson, K.G.: Electron microscopic identification of autonomic nerve endings. Nature (Lond.) 210, 756 (1966)
Ruskell, G.L.: Sympathetic innervation of the ciliary muscle in monkeys. Exp. Eye Res. 16, 183–190 (1973)
Tranzer, J.P., Richards, J.G.: Fine structural aspects of the effect of 6-hydroxydopamine on peripheral adrenergic neurons. In: 6-Hydroxydopamine and catecholamine neurons, edit. by T. Malmfors and H. Thoenen, p. 15–31. Amsterdam-London: North-Holland 1971
Tranzer, J.P., Thoenen, H.: Electron microscopic localization of 5-hydroxydopamine (3, 4, 5-trihydroxyphenyl-ethylamine), a new ‘false’ sympathetic transmitter. Experientia (Basel) 23, 743–745 (1967)
Tranzer, J.P., Thoenen, H.: An electron microscopic study of selective, acute degeneration of sympathetic nerve terminals after administration of 6-hydroxydopamine. Experientia (Basel) 24, 155–156 (1968)
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This work was supported in part by a research grant from the Ministry of Education, Japan
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Akagi, Y., Ibata, Y. & Sano, Y. The sympathetic innervation of the ciliary body and trabecular meshwork of the cat. Cell Tissue Res. 173, 261–269 (1976). https://doi.org/10.1007/BF00221379
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DOI: https://doi.org/10.1007/BF00221379