Spinal Factors in Sympathetic Regulation

Schramm, Lawrence P.

doi:10.1007/978-1-4615-9471-0_11

Cited by 11 publications

(5 citation statements)

References 156 publications

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“…This observation has a bearing on the much debated issue of whether or not axon collaterals emanate from SPNs (see, for example, Schramm, 1986). Morphological evidence as to the existence of axon collaterals is inconsistent.…”

Section: Discussionmentioning

confidence: 99%

“…The most interesting aspect of this study relates to the findings that the IPSPs could be evoked by ventral root stimulation and that these IPSPs could be blocked not only by strychnine but also by the nicotinic antagonists, hexamethonium and d-tubocurarine. This observation has a bearing on the much debated issue of whether or not axon collaterals emanate from SPNs (see, for example, Schramm, 1986). Morphological evidence as to the existence of axon collaterals is inconsistent.…”

Section: Discussionmentioning

confidence: 99%

“…Sympathetic preganglionic neurones (SPNs) constitute the final common pathway site in the spinal cord whereby descending and segmental information related to cardiovascular activity is received, processed and transmitted to the peripheral sympathetic ganglia (Barman, 1984;Schramm, 1986;Coote, 1988). Viewed in this context, the available information concerning the electrical behaviour and synaptic transmission which underlie the transfer of information from central and peripheral neurones to SPNs is limited.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, IPSPs evoked by ventral root stimulation appear to represent a disynaptic event whereby nicotinic activation of a glycine-releasing interneurone results in a release of the inhibitory transmitter; this is then analogous to the Renshaw cell circuitry of the spinal motoneurones. INTRODUCTION Sympathetic preganglionic neurones (SPNs) constitute the final common pathway site in the spinal cord whereby descending and segmental information related to cardiovascular activity is received, processed and transmitted to the peripheral sympathetic ganglia (Barman, 1984;Schramm, 1986;Coote, 1988). Viewed in this context, the available information concerning the electrical behaviour and synaptic transmission which underlie the transfer of information from central and peripheral neurones to SPNs is limited.…”

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confidence: 99%

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Inhibitory postsynaptic potentials in neonatal rat sympathetic preganglionic neurones in vitro.

Dun

1989

The Journal of Physiology

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Inhibitory postsynaptic potentials in neonatal rat sympathetic preganglionic neurones in vitro.

Dun

1989

The Journal of Physiology

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“…Whether this is a property of cardiovascular SPN is unclear (Spanswick & Logan, 1990; Pickering et al 1994; Shen et al 1994; Logan et al 1996). Studies in spinal animals, including man, certainly indicate that some degree of sympathetic vasoconstrictor activity is present but that it is poorly regulated and unco‐ordinated (Schramm, 1986).…”

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confidence: 99%

Landmarks in understanding the central nervous control of the cardiovascular system

Coote

2007

Experimental Physiology

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In this Paton Lecture I have tried to trace the key experiments that have developed ideas on how the brain regulates the cardiovascular system. It is a personal view and inevitably, owing to constraints on space and time, I have not been able to cover areas such as the nucleus tractus solitarius and cardiac vagal neurones, although I acknowledge that some may consider the story is incomplete without them. Starting with the crucial discovery of vasomotor nerves and 'vasomotor tone', the patterns of activity in sympathetic nerves which led to the important idea of central oscillating networks of neurones are described. I discuss how this knowledge has informed current controversies on the origin of vasomotor activity in presympathetic neurones in the ventral medulla, which identify intrinsic pacemaker activity or synaptic input from multiple oscillators as prime mechanisms. I present an emerging view that the role of other regions of the brain, in particular supramedullary sites, has been underplayed. These regions are pivotal for the non-uniform distribution of cardiac output that is unique to each reflex and behavioural state. I discuss the most recent evidence for 'central command' neurones that offers a plausible explanation for how these patterns of sympathetic activity are achieved. Finally, I stress the importance of these current ideas to the understanding of pathological changes in sympathetic activity in cardiovascular diseases such as hypertension or congestive heart failure.

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Spinal cord lamina V and lamina VII interneuronal projections to sympathetic preganglionic neurons

Cabot

Alessi

Carroll

et al. 1994

J of Comparative Neurology

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This light and electron microscopic study sought to localize spinal cord interneurons that contribute to the normal and abnormal physiological regulation of spinal sympathetic preganglionic function. Sympathetic preganglionic neurons in caudal C8 through T4 of rat spinal cord were retrogradely labeled with wheat germ agglutinin (WGA) and/or cholera beta subunit (CT beta) following injections into the superior cervical ganglion (SCG). With two exceptions, the observed locations of retrogradely WGA- and CT beta-labeled sympathetic preganglionic neurons were as expected from previous studies. The exceptions were restricted populations of cells in caudal C8 and rostral T1 spinal segments. These neurons were classified as ventrolateral (vlSPN) and ventromedial (vmSPN) sympathetic preganglionic neurons; their somata and dendrites encircled dorsolateral lamina IX motoneurons. Only WGA was transported transneuronally following the retrograde labeling of sympathetic preganglionic neurons. Transneuronally WGA-labeled spinal interneurons were located principally in the reticulated division of lamina V and dorsolateral lamina VII. A strict segmental organization was observed. All transneuronally labeled interneurons were ipsilateral to, and coextensive with, retrogradely WGA-labeled sympathetic preganglionic neurons. Electron microscopic observations suggested that retrograde transsynaptic passage of WGA occurred within the sympathetic preganglionic neuropil and showed further that similar classes of organelles were WGA immunoreactive in retrogradely labeled sympathetic preganglionic neurons and in transneuronally labeled lamina V and lamina VII neurons: 1) cisternae and vesicles at the trans face of the Golgi apparatus, 2) large endosomes/dense bodies, and 3) multivesicular bodies. The data are consistent with two hypotheses: 1) Somatic and visceral primary afferent inputs to thoracic spinal cord modify segmental sympathetic preganglionic function through activation of a disynaptic pathway involving lamina V and/or lamina VII interneurons, and 2) long-loop propriospinal pathways access sympathetic preganglionic neurons through symmetrical, segmental interneuronal circuitry.

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Spinal Factors in Sympathetic Regulation

Cited by 11 publications

References 156 publications

Inhibitory postsynaptic potentials in neonatal rat sympathetic preganglionic neurones in vitro.

Inhibitory postsynaptic potentials in neonatal rat sympathetic preganglionic neurones in vitro.

Landmarks in understanding the central nervous control of the cardiovascular system

Spinal cord lamina V and lamina VII interneuronal projections to sympathetic preganglionic neurons

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