Summary
The development of synaptic interconnections between co-cultured explants of central and peripheral nervous tissue from chick embryos has been investigated by light and electron microscopy. Two sets of co-cultured explants were used: (a) dorsal root ganglion (DRG) and spinal cord and (b) retina and tectum. Both sets of co-cultured explants became linked by bundles of fibres but the most consistent results were obtained with the DRG-spinal cord explants. Thus axons from the DRG extended large distances across the culture substrate to reach and enter mainly the dorsal horn region of the spinal cord explants. In contrast retina-tectum links were less frequently established and were less extensive, possibly because there are fewer cells in retinal explants capable of establishing contacts in tectal explants than there are cells in DRG explants capable of establishing contacts in the spinal cord. In order to distinguish between synapses involving only neuronal elements within an expiant and those involving ingrowing fibres, fibre bundles linking adjacent explants were transected and the preparations fixed two to six hours later. Electron microscope study of such cultures revealed degenerating neurites and terminals in the spinal cord explants receiving DRG fibres but none in the corresponding DRG explants. Retinal explants contain numerous synapses of many types but degenerating terminals could not be found within the retinal explants after nerve fibre transections. Degenerating neurites and terminals were found within tectal explants but they were fewer and more difficult to locate than those found within spinal cord explants. The reasons for such differences are discussed.
Similar content being viewed by others
References
Bird MM, James DW (1974) An ultrastructural and electrophysiological study of the development of neuromuscular junctions between previously dissociated fetal rat cells in vitro. Cell Tissue Res 155: 269–282
Blank NK, Seil FJ, Leiman AL (1983) Climbing fibres in mouse cerebellum co-cultured with inferior olive. Brain Res 271: 135–140
Bunge MB, Bunge RP, Peterson ER (1967) The onset of synapse formation in spinal cord cultures as studied by electron microscopy. Brain Res 6: 725–749
Crain SM (1983) In: Pfeiffer SE (ed) Neuroscience approached through cell culture. CRC Press, pp 1–33
Crain SM, Peterson ER (1967) Onset and development of functional interneuronal connections in explants of rat spinal cord ganglia during maturation in culture. Brain Res 6: 750–762
Crain SM, Alfei L, Peterson ER (1970) Neuromuscular transmission in cultures of adult human and rodent skeletal muscle after innervation in vitro by fetal rodent spinal cord. J Neurobiol 1: 471–489
Crain SM, Peterson ER (1974) Enhanced afferents synaptic functions in fetal mouse cord-sensory ganglion explants following NGF-induced ganglion hypertrophy. Brain Res 79: 145–152
Crain SM, Peterson ER (1975) Development of specific sensory-evoked synaptic networks in fetal mouse cord-brain stem cultures. Science 188: 275–278
Fischbach GD (1972) Synapse formation between dissociated nerve and muscle cells in low density cell cultures. Dev Biol 28: 407–429
Gähwiler BH (1975) Mixed cultured of cerebellum and inferior olive: generation of complex spikes in purkinje cells. Brain Res 145: 168–172
Nakajima Y, Kidokoro Y, Klier F (1980) The development of functional neuromuscular junctions in vitro: an ultrastructural and physiological study. Dev Biol 77: 52–72
Peterson ER, Crain SM (1982) Preferential growth of neurites from fetal mouse dorsal root ganglia in relation to specific regions of co-cultured spinal cord explants. Dev Brain Res 2: 363–383
Smalheiser NR (1981) Positional specificity tests in co-cultures of retinal and tectal explants. Brain Res 213: 493–499
Smalheiser NR, Crain SM (1978) Formation of functional retino tectal connections in co-cultures of fetal mouse explants. Brain Res 148: 484–492
Smalheiser NR, Crain SM, Bornstein MB (1981) Development of ganglion cells and their axons in organized cultures of fetal retinal explants. Brain Res 204: 159–178
Smalheiser NR, Peterson ER, Crain SM (1982) Specific neuritic pathways and arborizations formed by fetal mouse dorsal root ganglion cells within organized spinal cord explants in culture: a peroxidase labeling study. Dev Brain Res 2: 383–395
Varon S (1979) In vitro studies of developing neural tissues and cells: past and prospective contributions. In: Schmitt FO (ed) The Neurosciences Second Study Program. Rockefeller University Press, New York
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bird, M.M. Establishment of synaptic connections between explants of embryonic neural tissue in culture: experimental ultrastructural studies. Exp Brain Res 57, 337–347 (1985). https://doi.org/10.1007/BF00236539
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00236539