Summary
The nerve terminals of neuromuscular junctions in the rat diaphragm, extensor digitorum longus muscle and soleus muscle have been studied in animals between 3 weeks and 2.5 years of age using methylene blue stain and light microscopy. Dimensions, structure and organization of the nerve terminals were shown to change during life at various rates in different muscles and postnatal periods. The area and length of the terminals increase in all three muscles until young adult age. Later these dimensions continue to increase in the extensor digitorum longus and soleus muscles. In the diaphragm only the length increases, and this occurs late in adult life. The area also increases in relation to the diameter of the corresponding muscle fiber. Adult soleus terminals are more elongated than terminals in the diaphragm and extensor digitorum longus muscle. During adult life the extension of nerve terminals in relation to muscle fiber length increases in the extensor digitorum longus and soleus muscles, but is almost unchanged in the diaphragm. The nerve terminal branches are mainly coarse and irregular in young animals, but possess varying numbers of varicosities in adult animals. The number of varicosities is high in the extensor digitorum longus muscle and low in the diaphragm. In old animals the number of varicosities tends to be reduced. With increasing age the nerve terminal branches become organized in distinct groups with increasing distance between the groups. This is prominent in the soleus.
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References
Balice-Gordon RJ, Lichtman JW (1990) In vivo visualization of the growth of pre- and postsynaptic elements of neuromuscular junctions in the mouse. J Neurosci 10:894–908
Balice-Gordon RJ, Breedlove SM, Bernstein S, Lichtman JW (1990) Neuromuscular junctions shrink and expand as muscle fiber size is manipulated: in vivo observations in the androgensensitive bulbocavernosus muscle of mice. J Neurosci 10:2660–2671
Banker BQ, Kelly SS, Robbins N (1983) Neuromuscular transmission and correlative morphology in young and old mice. J Physiol 339:355–375
Cardasis CA (1983) Ultrastructural evidence of continued reorganization at the aging (11–26 months) rat soleus neuromuscular junction. Anat Rec 207:399–415
Cardasis CA, Padykula HA (1981) Ultrastructural evidence indicating reorganization at the neuromuscular junction in the normal rat soleus muscle. Anat Rec 200:41–59
Coërs C, Woolf AL (1959) The innervation of muscle. A biopsy study. Blackwell, Oxford
Fagg GE, Scheff SW, Cotman CW (1981) Axonal sprouting at the neuromuscular junction of adult and aged rats. Exp Neurol 74:847–854
Gutmann E, Hanzlíková V (1965) Age changes of motor endplates in muscle fibres of the rat. Gerontologia 11:12–24
Kelly SS, Robbins N (1983) Progression of age changes in synaptic transmission at mouse neuromuscular junctions. J Physiol 343:375–383
Kelly SS, Robbins N (1987) Statistics of neuromuscular transmitter release in young and old mouse muscle. J Physiol 385:507–516
Korneliussen H, Wærhaug O (1973) Three morphological types of motor nerve terminals in the rat diaphragm, and their possible innervation of different muscle fiber types. Z Anat Entwicklungsgesch 140:73–84
Kuno M, Turkanis SA, Weakly JN (1971) Correlation between nerve terminal size and transmitter release at the neuromuscular junction of the frog. J Physiol 213:545–556
Labovitz SS, Robbins N, Fahim MA (1984) Endplate topography of denervated and disused rat neuromuscular junctions: comparison by scanning and light microscopy. Neuroscience 11:963–971
Lichtman JW, Magrassi L, Purves D (1987) Visualization of neuromuscular junctions over periods of several months in living mice. J Neurosci 7:1215–1222
Lnenicka GA, Atwood HL, Marin L (1986) Morphological transformation of synaptic terminals of a phasic motoneuron by long-term tonic stimulation. J Neurosci 6:2252–2258
Lømo T, Wærhaug O (1985) Motor endplates in fast and slow muscles of the rat: what determines their differences? J Physiol (Paris) 80:290–297
Lømo T, Massoulié J, Vigny M (1985) Stimulation of denervated rat soleus muscle with fast and slow activity patterns induces different expression of acetylcholinesterase molecular forms. J Neurosci 5:1180–1187
Nyström B (1968) Postnatal development of motor nerve terminals in “slow-red” and “fast-white” cat muscles. Acta Neurol Scand 44:363–383
Ogata T, Yamasaki Y (1985) The three-dimensional structure of motor endplates in different fiber types of rat intercostal muscle. A scanning electron-microscopic study. Cell Tissue Res 241:465–472
Pestronk A, Drachman DB, Griffin JW (1980) Effects of aging on nerve sprouting and regeneration. Exp Neurol 70:65–82
Slater CR (1982) Postnatal maturation of nerve-muscle junctions in hindlimb muscles of the mouse. Dev Biol 94:11–22
Smith DO, Rosenheimer JL (1982) Decreased sprouting and degeneration of nerve terminals of active muscles in aged rats. J Neurophysiol 48:100–109
Swatland HJ, Cassens RG (1972) Peripheral innervation of muscle from stress-susceptible pigs. J Comp Pathol 82:229–236
Tsujimoto T, Kuno M (1988) Calcitonin gene-related peptide prevents disuse-induced sprouting of rat motor nerve terminals. J Neurosci 8:3951–3957
Tuffery AR (1971) Growth and degeneration of motor end-plates in normal cat hind limb muscles. J Anat 110:221–247
Wernig A, Carmody JJ, Anzil AP, Hansert E, Marciniak M, Zucker H (1984) Persistence of nerve sprouting with features of synapse remodelling in soleus muscles of adult mice. Neuroscience 11:241–253
Wigston DJ (1989) Remodeling of neuromuscular junctions in adult mouse soleus. J Neurosci 9:639–647
Wigston DJ (1990) Repeated in vivo visualization of neuromuscular junctions in adult mouse lateral gastrocnemius. J Neurosci 10:1753–1761
Wærhaug O (1992) Species specific morphology of mammalian motor nerve terminals. Anat Embryol 185:111–116
Wærhaug O, Korneliussen H (1974) Morphological types of motor nerve terminals in rat hindlimb muscles, possibly innervating different muscle fiber types. Z Anat Entwicklungsgesch 144:237–247
Wærhaug O, Korneliussen H, Sommerschild H (1977) Morphology of motor nerve terminals on rat soleus muscle fibers reinnervated by the original and by a “foreign” nerve. Anat Embryol 151:1–15
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Wærhaug, O. Postnatal development of rat motor nerve terminals. Anat Embryol 185, 115–123 (1992). https://doi.org/10.1007/BF00185912
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DOI: https://doi.org/10.1007/BF00185912