GABA‐immunoreactive neurons and terminals in the lateral cervical nucleus of the cat

Broman, Jonas; Westman, Jan

doi:10.1002/cne.902740402

Cited by 31 publications

(16 citation statements)

References 40 publications

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“…In addition, the presumably cholinergic and excitatory synaptic contacts of motoneuron recurrent collaterals on other motoneurons and interneurons contain spherical vesicles (Cullheim et al, 1977;Lagerback et al, 1981a,b). On the other hand, other studies have found that GABAergic terminals usually contain spherical vesicles (Broman and Westman, 1988;Hayes, 1990,1991), and in the present study about half of the P terminals, which are presumably inhibitory, had spherical vesicles.…”

Section: Terminal Morphology and Functional Correlatesmentioning

confidence: 53%

Synaptic terminal coverage of primate triceps surae motoneurons

Starr¹,

Wolpaw²

1994

J of Comparative Neurology

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This study examined the synaptic terminal coverage of primate triceps surae (TS) motoneurons at the electron microscopic level. In three male pigtail macaques, motoneurons were labeled by retrograde transport of cholera toxin-horseradish peroxidase that was injected into TS muscles bilaterally and visualized with tetramethylbenzidine stabilized with diaminobenzidine. Somatic, proximal dendritic, and distal dendritic synaptic terminals were classified by standard criteria and measured. Overall and type-specific synaptic terminal coverages and frequencies were determined. Labeled cells were located in caudal L5 to rostral S1 ventral horn and ranged from 40 to 74 microns in diameter (average, 54 microns). The range and unimodal distribution of diameters, the label used, and the presence of C terminals on almost all cells indicated that the 15 cell bodies and associated proximal dendrites analyzed here probably belonged to alpha-motoneurons. Synaptic terminals covered 39% of the cell body membrane, 60% of the proximal dendritic membrane, and 40% of the distal dendritic membrane. At each of these three sites, F terminals (flattened or pleomorphic vesicles, usually symmetric active zones, average contact length 1.6 microns) were most common, averaging 52%, 56%, and 58% of total coverage and 56%, 57%, and 58% of total number of cell bodies, proximal dendrites, and distal dendrites respectively. S terminals (round vesicles, usually asymmetric active zones, average contact length 1.3 microns) averaged 24%, 29%, and 33% of coverage and 33%, 35%, and 36% of number at these three sites, respectively. Thus, S terminals were slightly more prominent relative to F terminals on distal dendrites than on cell bodies. C terminals (spherical vesicles, subsynaptic cisterns associated with rough endoplasmic reticulum, average contact length 3.5 microns) constituted 24% and 11% of total terminal coverage on cell bodies and proximal dendrites, respectively, and averaged 11% and 6% of terminal number at these two locations. M terminals (spherical vesicles, postsynaptic Taxi bodies, some with presynaptic terminals, average contact length 2.7 microns) were absent on cell bodies and averaged 3% and 7% of total coverage and 2% and 5% of terminals on proximal and distal dendrites, respectively. Except for M terminals, which tended to be smaller distally, terminal contact length was not correlated with location. Total and type-specific coverages and frequencies were not correlated with cell body diameter. Primate TS motoneurons are similar to cat TS motoneurons in synaptic terminal morphology, frequency, and distribution. However, primate terminals appear to be smaller, so that the fraction of membrane covered by them is lower.

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Section: Terminal Morphology and Functional Correlatesmentioning

confidence: 53%

Synaptic terminal coverage of primate triceps surae motoneurons

Starr¹,

Wolpaw²

1994

J of Comparative Neurology

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“…reactive substances in the LCN (Blomqvist et al, 1985a; Giesler ondarv antibodies were used for evaluating the distribution of and Elde, 1985;Broman and Westman, 1988;Blomqvist, 1989a,b, 1990;Maxwell et al, 1989) including an enrichment of Glu-LI in SCT terminals ). However, the findings in these studies do not give any evidence regarding the neurotransmitter used by the CTT neurons.…”

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confidence: 99%

Cervicothalamic tract terminals are enriched in glutamate-like immunoreactivity: an electron microscopic double-labeling study in the cat

Broman

Ottersen

1992

J. Neurosci.

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The distribution of glutamate-like immunoreactivity (Glu-LI) in the thalamic ventral posterolateral nucleus (VPL) of cats was studied with the EM immunogold technique in order to identify nerve terminal populations that may use glutamate as a neurotransmitter. The investigation was focused on cervicothalamic tract (CTT) terminals, which were labeled by WGA-HRP transported anterogradely from injection sites in the lateral cervical nucleus (LCN). The amount of Glu-LI in different profiles was evaluated quantitatively by counting the number of gold particles and then calculating the areal density of gold particles over different profile types. The highest density of gold particles was found over terminals with morphologic characteristics of terminals of cortical origin (RS terminals), a finding that further supports the glutamatergic nature of these terminals suggested by previous studies. Enrichment of Glu-LI was also found in CTT terminals and in non-peroxidase-labeled terminals with the same morphologic characteristics as CTT terminals (RL terminals). The labeling density over these terminals was about twice the average tissue density of gold particles. The labeling density over large VPL neuronal cell bodies was on average 127%, and that over vesicle-containing dendritic appendages and truncs (presynaptic dendrites) about 80%, of the average tissue density of gold particles. Immunogold labeling with antiserum against glutamine (Gln) indicated low levels of Gln-like immunoreactivity in CTT terminals and a high Glu:Gln ratio as compared to astrocytes and the average Glu:Gln ratio in the VPL. The present findings provide further support for a transmitter role of glutamate in terminals of ascending somatosensory afferents to the VPL, including the CTT. Taken together with previous findings of an enrichment of Glu-LI in terminals of the spinocervical tract (Broman et al., 1990), our results suggest that synaptic transmission in the spinocervicothalamic pathway is dependent on the release of glutamate both at the levels of the LCN and the VPL.

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“…In the cat LCN, there are several lines of anatomic and physiologic evidence for the presence of local circuit neurons (Gordon and Jukes 1963;Horrobin 1966;Westman 1971;Craig and Tapper 1978;Craig and Burton 1979;Flink and Westman 1986). These putative local circuit neurons conform with respect to location, number, size and other morphologic characterstics, with the GABA-immunoreactive neurons in the cat LCN (Broman and Westman 1988). On basis of the similarities in organization of the cat and raccoon LCN, it appears likely that the GABA-positive neurons in the raccoon LCN also constitute a population of inhibitory local circuit neurons.…”

Section: Discussionmentioning

confidence: 99%

“…Second, there are differences in neuronal sizes, neurochemical organization and physiological characteristics along the mediolateral extent of the LCN in cats. Small cells are preferentially located in the medial part of the nucleus (Craig and Burton 1979), as is also a small population of GABA-immunoreactive neurons (Broman and Westman 1988). Further, substance P-immunoreactive fibers are concentrated in the medial part of the cat LCN (Blomqvist et al 1985b;Giesler and Elde 1985;Broman and Blomqvist 1989a).…”

Section: Introductionmentioning

confidence: 99%

“…These findings indicate the presence in raccoons of a functional segregation similar to that in cats along the transverse extent of the LCN, an organization different from that found in the primate LCN. However, with respect to another important constituent of the mediolateral organization in cats, that is, the medial location of GABA-immunoreactive neurons (Broman and Westman 1988), nothing is yet known concerning the raccoon LCN.…”

Section: Introductionmentioning

confidence: 99%

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The raccoon lateral cervical nucleus: mediolateral organization of GABA-positive and GABA-negative neurons and fibers

Broman

Pubols

1996

Anat Embryol

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In the lateral cervical nucleus (LCN) of the cat, GABA-immunoreactive neurons and substance P-immunoreactive fibers are concentrated in the medial part of the nucleus, whereas in the monkey LCN no preferential locations have been identified. In raccoons, substance P-immunoreactive fibers display a distribution pattern similar to that in cats. However, the presence and distribution of GABA-immunoreactive neurons in the raccoon LCN has not been examined, and it is therefore not known whether raccoons are similar to cats or primates in this respect. Thus, in the present study, the raccoon LCN was examined for the presence and distribution of GABA-immunoreactive cells with respect to their numbers, locations, and sizes. The distribution of GABA-positive fibers and varicosities within the LCN was also investigated. The results of measurements of cross-sectional areas of LCN neurons indicate a trend toward decreasing cell size along the dorsolateral to medial axis of the raccoon LCN. Compared to neurons of the centrally located ventromedial division, neurons are statistically significantly larger in the dorsolateral division and smaller in the medial division of the nucleus. Cell counts in post-embedding-stained semithin sections through the nucleus revealed an average of 8,700 neurons per LCN. Approximately 4% of LCN neurons are GABA-immunoreactive. These neurons are small and most (80%) of them are located in the medial third of the LCN. In contrast, GABA-immunoreactive fibers and varicosities are present in about equal density throughout the raccoon LCN. Thus, the distributions of GABA-immunoreactive neurons and neuron sizes in the raccoon LCN conform closely to those in cats. Together with previous observations in cats and raccoons, the present findings support the notion that these small GABA-immunoreactive neurons may be local circuit inhibitory neurons and indicate the presence of a mediolateral segregation that may be of fundamental importance for the functional organization of the carnivore LCN.

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GABA‐immunoreactive neurons and terminals in the lateral cervical nucleus of the cat

Cited by 31 publications

References 40 publications

Synaptic terminal coverage of primate triceps surae motoneurons

Synaptic terminal coverage of primate triceps surae motoneurons

Cervicothalamic tract terminals are enriched in glutamate-like immunoreactivity: an electron microscopic double-labeling study in the cat

The raccoon lateral cervical nucleus: mediolateral organization of GABA-positive and GABA-negative neurons and fibers

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