Morphology of sympathetic preganglionic neurons in the neonatal rat spinal cord: An intracellular horseradish peroxidase study

Forehand, Cynthia J.

doi:10.1002/cne.902980306

Cited by 49 publications

(23 citation statements)

References 33 publications

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“…Consistent with NK-1 binding studies (Buck et al, 1986;Charlton and Helke, 1985;Helke et al, 1986;Shults et al, 1984;Yashpal et al, 19901, we found SPR-immunoreactive neurons in each of the three major regions of the rat spinal cord that contain sympathetic preganglionic neurons (SPN), the intermediolateral cell column, the intercalated nucleus, and the central autonomic nucleus. The immunohistochemical analysis revealed that many of the SPR-immunoreactive neurons had dendrites that coursed mediolaterally from the IML to the central canal, which is consistent with a morphological analysis of antidromically activated SPNs in the IML (Forehand, 1990). Heavily labeled dendrites in the and dendritic surfaces of labeled neurons and that most of the labeled membrane is not apposed by SP-immunoreactive terminals (Liu et al, 1994).…”

Section: Laminar Distribution Of Spr-immunoreactive Neuronsmentioning

confidence: 56%

Morphological characterization of substance P receptor‐immunoreactive neurons in the rat spinal cord and trigeminal nucleus caudalis

Brown

Liu

Maggio

et al. 1995

J of Comparative Neurology

232

125

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Although there is considerable evidence that primary afferent-derived substance P contributes to the transmission of nociceptive messages at the spinal cord level, the population of neurons that expresses the substance P receptor, and thus are likely to respond to substance P, has not been completely characterized. To address this question, we used an antibody directed against the C-terminal portion of the rat substance P receptor to examine the cellular distribution of the receptor in spinal cord neurons. In a previous study, we reported that the substance P receptor decorates almost the entire dendritic and somatic surface of a subpopulation of spinal cord neurons. In the present study we have taken advantage of this labeling pattern to identify morphologically distinct subpopulations of substance P receptor-immunoreactive neurons throughout the rostral-caudal extent of the spinal cord. We observed a dense population of fusiform substance P receptor-immunoreactive neurons in lamina I at all segmental levels. Despite having the highest concentration of substance P terminals, the substantia gelatinosa (lamina II) contained almost no substance P receptor-immunoreactive neurons. Several distinct populations of substance P receptor-immunoreactive neurons were located in laminae III-V; many of these had a large, dorsally directed dendritic arbor that traversed the substantia gelatinosa to reach the marginal layer. Extensive labeling was also found in neurons of the intermediolateral cell column. In the ventral horn, we found that labeling was associated with clusters of motoneurons, notably those in Onuf's nucleus in the sacral spinal cord. Finally, we found no evidence that primary afferent fibers express the substance P receptor. These results indicate that relatively few, but morphologically distinct, subclasses of spinal cord neurons express the substance P receptor. The majority, but not all, of these neurons are located in regions that contain neurons that respond to noxious stimulation.

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Section: Laminar Distribution Of Spr-immunoreactive Neuronsmentioning

confidence: 56%

Morphological characterization of substance P receptor‐immunoreactive neurons in the rat spinal cord and trigeminal nucleus caudalis

Brown

Liu

Maggio

et al. 1995

J of Comparative Neurology

232

125

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“…The described morphology was shown to be typical for SPNs in the lateral horn (Forehand, 1990;Shen & Dun, 1990) and has already been used as a criterion for positive identification of these neurones by other authors (Pickering, Spanswick & Logan, 1991). In addition, we have been able to label SPNs retrogradely (Y. Larmet, J. Krupp & P. Feltz, unpublished observations) after injection of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbo-cyanine perchlorate (DiI) into the adrenal medulla.…”

Section: Morphology Of Recorded Cellsmentioning

confidence: 72%

“…Since the dendritic processes of SPNs extend several hundred micrometres away from the cell soma (Bacon & Smith, 1988;Forehand, 1990), errors may arise from inadequate voltage control in these distal regions. If the synaptic currents we recorded originated in these regions, the time course and amplitude of these currents would probably be distorted by the filtering of the RC network of the distal dendrites.…”

Section: Site Of Origin Of Synaptic Currentsmentioning

confidence: 99%

Synaptic‐ and agonist‐induced chloride currents in neonatal rat sympathetic preganglionic neurones in vitro.

Krupp

Feltz

1993

The Journal of Physiology

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SUMMARY1. By using the whole-cell recording configuration of the patch-clamp technique in a spinal cord slice preparation, we have made recordings from visually identified neurones in the lateral horn of the thoracic and lumbar spinal cord of neonatal rats (newborn to 14 days postnatal).2. Some of the recorded neurones were labelled with the fluorescent dye Lucifer Yellow (n = 27). Their morphology was typical for sympathetic preganglionic neurones (SPNs). Based on the size of the cell soma and the electrophysiological properties, unlabelled neurones were also regarded as SPNs.3. Spontaneous synaptic activity of different patterns could be observed in 73 % of the recorded neurones (n = 106). It reversed at the chloride equilibrium potential (EC1) and could be reversibly blocked by strychnine (1-10 ,UM), but not by bicuculline (1O/tM) or SR95531 (5-10 sM).4. Synaptic activity could be elicited by focal electrical stimulation in the vicinity of the recorded neurone. These evokld synaptic events exhibited features similar to the spontaneous synaptic activity.5. Application of glycine (100 /,M-1 mM) by a fast microperfusion system induced a chloride current in twenty-seven out of thirty cells tested. The currents were reversibly blocked by strychnine (1-10 /M), but were only weakly sensitive to bicuculline (10 ,UM). Stability of current responses to glycine was increased by inclusion of ATP (4 mM) in the intracellular medium.6. Application of y-aminobutyric acid (GABA; 100 gM-1 mM) by the fast microperfusion system induced a chloride current in all twenty neurones tested.These currents were reversibly blocked by bicuculline (10 /tM).

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“…Other investigators using Golgi staining or intracellular labeling with HRP to study sympathetic preganglionic neurons in the cat have found no evidence of axon collaterals (13,21). Similarly, previous experiments on the sympathetic system in other species, including the neonatal rat (22,23) and the pigeon (24), would indicate collaterals on sympathetic preganglionic neurons are rare and are limited in structure and extent. But, in view of the current results, it might be worthwhile to explore these regions again by using intracellular labeling with neurobiotin.…”

Section: Discussionmentioning

confidence: 91%

Axon collaterals indicate broad intraspinal role for sacral preganglionic neurons.

Morgan

Groat

Felkins

et al. 1991

Proc. Natl. Acad. Sci. U.S.A.

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The classic view of preganglionic neurons in spinal autonomic nuclei is that they convey information exclusively from the central nervous system to autonomic neurons in peripheral ganglia. The present morphological study in the cat sacral spinal cord demonstrates that these neurons may also make abundant synaptic connections within the spinal cord.Neurons labeled intracellularly with neurobiotin or horseradish peroxidase exhibited an expansive distribution of axon collaterals in spinal cord laminae I, V, VII, Vm, IX, X, and the ventrolateral funiculi. This broad-ranging axon-collateral system, which has the potential for multiple neuronal contacts, indicates widespread integrative functions for sacral preganglionic neurons within the spinal cord, in addition to functions currently known in the periphery.The preganglionic neuron of the autonomic nervous system represents the first component of a two-neuron efferent pathway that carries information from the central nervous system to the visceral organs. These neurons, which are located in the spinal cord-many of them in the intermediolateral cell column-and in visceral motor nuclei in the brainstem, integrate afferent inputs from various central and peripheral sources and then convey efferent signals to ganglion cells in the peripheral nervous system.According to traditional concepts, preganglionic neurons have purely peripheral functions and do not make efferent connections with other neurons in the central nervous system. However, in the sacral parasympathetic preganglionic pathways to the urinary bladder of the cat, a bilateral and intersegmental recurrent inhibitory mechanism has been identified using electrophysiological techniques (1-3). These findings raise the possibility that sacral preganglionic neurons have an axon-collateral system that makes synaptic contacts with inhibitory interneurons within the spinal cord similar to axon-collateral pathways that have been identified for somatic motoneurons (4). Numerous morphological studies have failed to confirm the existence of sacral preganglionic axon collaterals (5-9). However, in the present experiments extensive axon-collateral systems have been revealed by using intracellular labeling techniques. MATERIALS AND METHODSIn these experiments, 20 male cats were anesthetized with diallylbarbituric acid (0.3 mg/kg) and urethane (2.4 mg/kg i.p.) supplemented with sodium pentobarbital (30 mg/kg i.v.), as needed. After a laminectomy, neurons in the sacral spinal cord were activated antidromically by electrical stimulation of the S2 ventral root and identified as preganglionic neurons by having stimulus thresholds two to three times higher than those of motoneurons and by their slow conduction velocities of 4-12 m/sec. These neurons were located in lateral lamina VII in an area of the sacral parasympathetic nucleus known to contain bladder preganglionic neurons (6, 8) and had conduction velocities typical of these cells (1, 10). Electrodes were judged to be intracellular when resting membrane potentials dro...

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Morphology of sympathetic preganglionic neurons in the neonatal rat spinal cord: An intracellular horseradish peroxidase study

Cited by 49 publications

References 33 publications

Morphological characterization of substance P receptor‐immunoreactive neurons in the rat spinal cord and trigeminal nucleus caudalis

Morphological characterization of substance P receptor‐immunoreactive neurons in the rat spinal cord and trigeminal nucleus caudalis

Synaptic‐ and agonist‐induced chloride currents in neonatal rat sympathetic preganglionic neurones in vitro.

Axon collaterals indicate broad intraspinal role for sacral preganglionic neurons.

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