Axon Populations in Cat Lingual and Chorda Tympani Nerves

Abstract

The lingual and chorda tympani nerves from five cats were examined so that normal axonal populations could be determined. After perfusion fixation, the chorda tympani and lingual nerves were removed and processed, and sections were taken from individual and combined nerves for both light and electron microscopy. The chorda tympani remained as a distinct group of smaller axons for at least 4 mm distal to its junction with the lingual nerve. The mean number ± S.D. of myelinated axons in the chorda tympani central to the junction was 1322 (± 268) and in the lingual nerve central to the junction, 3227 (± 510). The counts were not significantly different distal to the junction, and there were no side-to-side differences. Mean myelinated axon circumferences were significantly smaller in the chorda tympani (12.86 ± 0.87) than in the lingual nerve (22.79 ± 1.99; p < 0.01). The mean size of axons in the chorda tympani was slightly but consistently larger on the left (13.1 ± 0.73) than on the right side (12.61 ± 1.01; p < 0.05). Distal to the junction, the average proportion of non-myelinated axons was 44% in both chorda tympani and lingual nerves.

Get full access to this article

View all access options for this article.

References

Biedenbach MA , Beurman RW , Brown AC (1975). Graphic-digitizer analysis of axon spectra in ethmoidal and lingual branches of the trigeminal nerve. Cell Tissue Res 157:341-352.

Biedenbach MA , Chan KT ( 1971). Tongue mechanoreceptors: comparison of afferent fibers in the lingual nerve and chorda tympani. Brain Res 35:584-588.

Beidler LM (1969). Innervation of rat fungiform papilla. In: Pfaffmann C , editor. Olfaction and taste III. New York: Rockefeller University Press, 352-369.

Blackburn CW , Bramley PA (1989). Lingual nerve damage associated with the removal of lower third molars. Br Dent J 167:103-107.

Blom S. ( 1960). Afferent influences on tongue muscle activity. Acta Physiol Scand 49:3-97.

Dubner R. , Sessle BJ , Storey AT (1978). The neural basis of oral and facial function. New York: Plenum Press, 241.

Eppley BL , Snyders RV (1991). Microanatomic analysis of the trigeminal nerve and potential nerve graft donor sites. J Oral Maxillofac Surg 49:612-618.

Erici I. , Folkow B. , Uvnas B. (1952). Sympathetic vasodilator nerves to the tongue of the cat. Acta Physiol Scand 25:1-9.

Erici I. , Uvnas B. (1952). Efferent and antidromic vasodilator impulses to the tongue in the chorda-lingual nerve of cat. Acta Physiol Scand 25:10-14.

10.

Farbman AI , Hellekant G. (1978). Quantitative analyses of the fiber population in rat chorda tympani nerves and fungiform papillae. Am J Anat 153:509-522.

11.

Foley JO (1945). The sensory and motor axons of the chorda tympani . Proc Soc Exp Biol Med 60:262-267.

12.

Girod SC , Neukam FW , Girod B. , Reumann K. , Semrau H. (1989). The fascicular structure of the lingual nerve and the chorda tympani: an anatomic study. J Oral Maxillofac Surg 47:607-609.

13.

Heasman PA , Beynon Adg (1986). Quantitative diameter analysis of lingual nerve axons in man. J Dent Res 65:1016-1019.

14.

Hellekant G. (1977). Vasodilator fibers to the tongue in the chorda tympani proper nerve. Acta Physiol Scand 99:292-299.

15.

Hiura A. , Ishizuka H. , Sakamoto Y. (1990). Electron microscopic study of the effect of capsaicin on the mouse chorda tympani nerves. Arch Oral Biol 35:913-916.

16.

Holland GR (1978). Fiber numbers and sizes in the inferior alveolar nerve of the cat. J Anat 327:343-352.

17.

Holland GR , Robinson PP (1987). A morphological study of the collateral reinnervation of the cat's canine tooth. Exp Neurol 98 :489-498.

18.

Holland GR , Robinson PP (1990a). Cell counts in the trigeminal ganglion of the cat after inferior alveolar nerve injuries. J Anat 171:179-186.

19.

Holland GR , Robinson PP (1990b). The number and size of axons central and peripheral to inferior alveolar nerve injuries in the cat. J Anat 173:129-137.

20.

Hughes S. , Smith ME (1988). Effect of nerve section on B-endorphin X-melanotropin immunoreactivity in motor neurons of normal and dystrophic mice. Neurosci Lett 92:1-7.

21.

Mason DA (1988). Lingual nerve damage following lower third molar surgery. Int J Maxillofac Surg 17:290-294.

22.

Matthews B. , Robinson PP (1980). The course of post-ganglionic sympathetic fibers distributed with the trigeminal nerve in the cat. J Physiol (Lond) 303:391-401.

23.

Mozsary PG , Middleton RA (1984). Microsurgical reconstruction of the lingual nerve . J Oral Maxillofac Surg 42:415-420.

24.

Robinson PP (1981). Reinnervation of teeth, mucous membrane and skin following section of the inferior alveolar nerve in the cat. Brain Res 220:240-253.

25.

Robinson PP (1988). The characteristics and regional distribution of afferent fibers in the chorda tympani of the cat. J Physiol (Lond) 406:345-357.

26.

Robinson PP (1989). The reinnervation of the tongue and salivary glands after lingual nerve injuries in cats. Brain Res 483:259-271.

27.

Rotshenker S. , Tal M. (1985). The transneuronal induction of sprouting and synapse formation in intact mouse muscles. J Physiol (Lond) 360:387-396.

28.

Smith EE , Harn SD ( 1989). Presence of nerve cell bodies in the lingual nerve in the third molar area. J Oral Maxillofac Surg 47:931-935. van Buskirk J. (1945). The seventh nerve complex . J Comp Neurol 82:303.