Cytoarchitectonic analysis of the bullfrog (Rana catesbeiana) spinal cord by means of electron microscopy with special reference to distribution of microneurons

1977 ◽  
Vol 176 (1) ◽  
pp. 101-119 ◽  
Author(s):  
Hiroshi Sasaki
Keyword(s):  
Electron Microscopy ◽  
Spinal Cord ◽  
Special Reference ◽  
Rana Catesbeiana

Vesicular system associated with spermiogenesis of bullfrog

1987 ◽  
Vol 45 ◽  
pp. 818-819
Author(s):  
K. C. Liu ◽  
S. F. Tsay
Keyword(s):  
Electron Microscopy ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Reproductive System ◽  
Seminiferous Tubule ◽  
Rana Catesbeiana ◽  
Routine Procedure ◽  
Electron Microscopic ◽  
Twisted Tubules ◽  
Electron Lucent

In the histologic and electron microscopic study of the male reproductive system of bullfrog, Rana catesbeiana, a vesicular system associated with spermiogenesis was observed. It appeared in the lumenal space of the seminiferous tubule (Fig. 1), in the heads of spermatids (Fig. 2), associated with the chromatins of the spermatid (Fig. 4). As deduced from sections, this vesicular system consisted of vesicles of various size or a large group of waving and twisted tubules (Fig. 3), After routine procedure of treatment for electron microscopy, the lumens of both of the vesicles and tubules were electron lucent.In human, vesicles and vesicular system associated with reproductive cell and tissue were reported. In abnormal spermiogenesis, flower-like body, actually vesicles, and giant vesicle associated with the head of spermatid were observed. In both cases the number of vesicle was limited from a single one to a few.

scholarly journals Comparative Electron Microscopy of Synapses in the Vertebrate Spinal Cord

1966 ◽  
Vol 1 (1) ◽  
pp. 67-80
Author(s):  
B. T. CHARLTON ◽  
E. G. GRAY
Keyword(s):  
Electron Microscopy ◽  
Spinal Cord ◽  
Synaptic Transmission ◽  
Tight Junctions ◽  
Presynaptic Inhibition ◽  
Grey Matter ◽  
Rare Occurrence ◽  
Lower Vertebrates ◽  
Mode Of Transmission ◽  
Comparative Electron

Synapses with a cleft with ‘thickened’ membranes and presynaptic vesicles and mitochondria occur commonly throughout the grey matter of the spinal cord of goldfish, frog and various mammals studied. Such synapses are generally thought to have a chemical mode of transmission. The absence or rare occurrence of presynaptic neurofilaments in fish and frog accounts for the failure to detect boutons by silver methods, and there is no need to postulate morphologically unspecialized synaptic contacts in the lower vertebrates as some light microscopists did. Both fish and frog show axo-somatic or axo-dendritic tight junctions, which could be sites of electrical synaptic transmission. No neuronal tight junctions have yet been seen in the mammalian spinal cord. Axo-axo-dendritic synapses have been seen in the frog and mammalian cord, but not so far in the fish. Such serial synapses may be responsible for presynaptic inhibition. Neuroglia of fish, frog and mammals have tight junctions at their apposed surfaces. These differ structurally from neuronal tight junctions. Neuroglia in fish cord have, in addition, desmosomes at their apposed surfaces.

scholarly journals High-Voltage Electron Microscopy Reveals Direct Synaptic Inputs from a Spinal Gastrin-Releasing Peptide System to Neurons of the Spinal Nucleus of Bulbocavernosus

Endocrinology ◽  
2010 ◽  
Vol 151 (1) ◽  
pp. 417-421 ◽  
Author(s):  
Hirotaka Sakamoto ◽  
Tatsuo Arii ◽  
Mitsuhiro Kawata
Keyword(s):  
Electron Microscopy ◽  
Spinal Cord ◽  
High Voltage ◽  
Lumbar Spinal Cord ◽  
Sexually Dimorphic ◽  
High Voltage Electron Microscopy ◽  
Synaptic Inputs ◽  
Gastrin Releasing Peptide ◽  
Voltage Electron ◽  
Lumbar Spinal

Abstract The spinal nucleus of bulbocavernosus (SNB) is a sexually dimorphic motor nucleus located in the anterior horn of the fifth and sixth lumbar segments of the spinal cord that plays a significant role in male sexual function. We recently found that a sexually dimorphic expression of gastrin-releasing peptide (GRP) in the lumbar spinal cord regulates male copulatory reflexes. Although it is reported that these systems are both profoundly regulated by circulating androgen levels in male rats, no direct evidence has been reported regarding GRP synaptic inputs onto SNB motoneurons. The aim of the current study was to determine the axodendritic synaptic inputs of spinal GRP neurons to SNB motoneurons. Immunoelectron microscopy, combined with a retrograde tracing technique using high-voltage electron microscopy (HVEM), provided a three-dimensional visualization of synaptic contacts from the GRP system in the lumbar spinal cord onto SNB motoneurons. HVEM analysis clearly demonstrated that GRP-immunoreactive axon terminals directly contact dendrites that extend into the dorsal gray commissure from the SNB. These HVEM findings provide an ultrastructural basis for understanding how the spinal GRP system regulates male sexual behavior.

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