A morphological and biochemical study of subcellular fractions of the guinea pig spinal cord

Ross, Leonard L.; Andreoli, V. M.; Marchbanks, R. M.

doi:10.1016/0006-8993(71)90570-1

Cited by 26 publications

(5 citation statements)

References 46 publications

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“…These latter synaptosomes were found in two subfractions of P1 (PIC and P1D) but were not distinguished on morphological grounds. Similar synaptosomes had previously been described by Ross, Andreoli, and Marchbanks (1971) in three subfractions of their PZ fraction of the guinea pig spinal cord.…”

Section: Introductionsupporting

confidence: 85%

Further observations of the ultrastructure of synaptosomes separated from spinal cord and medulla, with especial emphasis on the postsynaptic membrane

Jones

1976

J. Neurobiol.

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Synaptosomes from rat medulla and spinal cord have been examined in an attempt to formulate morphological criteria for distinguishing between those found in two subfractions of P1 (nuclear fraction). The mean diameter of those in the lighter of the subfractions (P1C) is 0.6 mum, with a preponderance in the range 0.4-0.6 mum and a minor peak at 0.7-0.8 mum. Subjunctional bodies are associated with 60.2% of the junctional regions in this subfraction. By contrast, those in the heavy subfraction (P1D) have a larger overall diameter (0.7 mum), a greater percentage of them have visible junctional regions (68.1% opposed to 51.6%), but of the junctional regions a lower percentage have associated subjunctional bodies (36.2%). The subjunctional bodies consist of a central core with five spokes radiating from it. The tips of the spokes are connected by fine strands which connect individual bodies to neighboring ones, as well as to the postsynaptic thickening. The persistence of subjunctional bodies in synaptosomes highlights the strength of the attachment between them and the postsynaptic thickening, and suggests that these bodies may be integral components of the "postsynaptic thickening complex." They may also help in the formulation of criteria by which different populations of these synaptosomes may be separated from each other.

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Section: Introductionsupporting

confidence: 85%

Further observations of the ultrastructure of synaptosomes separated from spinal cord and medulla, with especial emphasis on the postsynaptic membrane

Jones

1976

J. Neurobiol.

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“…These terminals can be found at a higher density than those assumed to belong to primary afferents. Ross et al (1971) showed that there is a difference in density between 5-HT-and NE-containing nerve endings prepared from guinea pig whole spinal cord. The results presented here are difficult to compare with theirs due to considerable methodological differences, to differences in the tissue used, and to the fact that 5-HT was not measured in gradient fractions from dorsal spinal cord.…”

Section: Discussionmentioning

confidence: 99%

“…Iversen and Johnston (1971) have shown that synaptosomes prepared from spinal cord that take up [3H]y-aminobutyric acid ([3H]GABA) were distributed around a maximum at a lower density than those capable of accumulating [14C]glycine. Ross et al (1971), in a study of guinea pig spinal cord synaptosomes, achieved a partial separation of nerve endings containing 5-hydroxytryptamine (5-HT) from those containing norepinephrine (NE) as transmitter on a discontinuous sucrose density gradient. There is considerable diversity even among neurons that all contain the peptide substance P (SP) as a transmitter in the spinal cord.…”

mentioning

confidence: 99%

“…It was also thought useful to investigate the position of SPcontaining nerve endings with regard to the density distribution of synaptosomes capable of accumulating [3H]GABA and [ 14C]glycine, especially as a new method of generating linear density gradients with very small slopes was developed for the present study. The distribution of nerve endings with the capacity to accumulate [3H]NE was measured because this transmitter has been shown to be present in nerve terminals within the spinal cord (Dahlstrom and Fuxe, 1965;Ross et al, 1971). Spinal cord tissue from rats treated with capsaicin as neonates were used in an effort to identify nerve endings belonging to capsaicin-sensitive primary afferents, such as those containing SPI.…”

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confidence: 99%

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Distribution of Spinal Cord Nerve Endings Containing Various Neurotransmitters on a Continuous Density Gradient

Bucsics

Mayer

Pabst

et al. 1984

Journal of Neurochemistry

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Homogenates of rat dorsal or ventral spinal cord were subjected to centrifugation on a continuous density gradient. The gradient was generated according to a new method with the aid of a microprocessor-controlled HPLC pump. The distribution of substance P-like immunoreactivity (SPI) and somatostatin-like immunoreactivity (SRIFI) across the gradient showed two peaks. The SPI peak seen at lower density was found only in dorsal spinal cord tissue. No peak of SPI was seen at this position in homogenates prepared from the spinal cords of capsaicin-pretreated rats. The second peak of SPI, found at a higher density, was accompanied by peaks in the levels of endogenous 5-hydroxytryptamine (5-HT), [14C]glycine, and [3H]norepinephrine uptake. This peak was seen at the same density in the dorsal and the ventral spinal cord. Tissue derived from capsaicin-pretreated rats exhibited one peak of SPI, accompanied by a maximum of [14C]glycine uptake. The uptake of [3H]gamma-aminobutyric acid ( [3H]GABA) was found to have a maximum at a somewhat lower density than that of [14C]glycine. It is concluded that the peak of SPI found at lower density in the dorsal spinal cord is associated with nerve endings belonging to capsaicin-sensitive primary afferents, while other endings, including those also containing 5-HT, are probably associated with the peak of SPI found at higher density.

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“…), and the medulla oblongata from 10 rats (1.10 g tissue wet wt.). The spinal cords were removed from the carcass and separated from the meninges within 3-5 min (Ross et al, 1970).…”

Section: Methodsmentioning

confidence: 99%

Interconversion of glycine and serine in a synaptosome fraction isolated from the spinal cord, medulla oblongata, telencephalon, and cerebellum of the rat

1973

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SUMMARYThe metabolism of glycine was studied in vitro using preparations of synaptosomes (P2) isolated from the spinal cord, medulla oblongata, telencephalon, and cerebellum of the rat. The content of aspartate, glutamate, glutamine, serine, threonine, glycine, and alanine was determined in the crude synaptosomal fraction (P2) from the four regions of the CNS. I n general, the content of the amino acids in the subcellular fraction from the medulla oblongata and spinal cord resembled one another whereas the same was true for the telencephalon and cerebellum. Significantly greater amounts of glutamate, aspartate, glutamine, and serine were found in the synaptosomal fraction of the telencephalon and cerebellum than in similar P2 fractions from the medulla oblongata and spinal cord. On the other hand, glycine had a higher content in the latter two preparations than in the P2 fractions from the telencephalon and cerebellum. [U-lCl-serine and [U-14C]-glycine were readily taken up by the crude synaptosomal fractions. The rate of conversion of serine to glycine appeared to be 18.5, 3.9, 2.9, and 2.7 times greater than the conversion.of glycine to serine in the incubated synaptosomal fractions from the cerebellum, spinal cord, medulla oblongata, and telencephalon, respectively. The conversion of serine carbons into glycine appeared to be 2.5, 1.9 and 1.6 times greater in the synaptosomal fraction from the cerebellum, spinal cord, and medulla oblongata than in similar preparations from the telencephalon. The data are discussed in terms of the possible synthesis pathway for the pool of glycine used as a transmitter.

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A morphological and biochemical study of subcellular fractions of the guinea pig spinal cord

Cited by 26 publications

References 46 publications

Further observations of the ultrastructure of synaptosomes separated from spinal cord and medulla, with especial emphasis on the postsynaptic membrane

Further observations of the ultrastructure of synaptosomes separated from spinal cord and medulla, with especial emphasis on the postsynaptic membrane

Distribution of Spinal Cord Nerve Endings Containing Various Neurotransmitters on a Continuous Density Gradient

Interconversion of glycine and serine in a synaptosome fraction isolated from the spinal cord, medulla oblongata, telencephalon, and cerebellum of the rat

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