Interaction of descending spinal sympathetic pathways and afferent nerves

Barman, Susan M.; Wurster, Robert D.

doi:10.1152/ajpheart.1978.234.3.h223

Cited by 10 publications

(6 citation statements)

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“…This long central delay suggests that multisynaptic or slowly conducting pathways mediate the inhibitory effect. In an early study of spinal sympathetic responses in the cat, there was evidence for a slowly conducting reticulospinal baroreceptor inhibitory pathway (Coote & Macleod, 1974;Barman & Wurster, 1978). However, there is also evidence that at least some SPNs can be inhibited by baroreceptors via a fast reticulospinal projection McCall, Gebber & Barman, 1977).…”

Section: Discussionmentioning

confidence: 99%

Chemical mediators of spinal inhibition of rat sympathetic neurones on stimulation in the nucleus tractus solitarii.

Lewis

Coote

1995

The Journal of Physiology

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1. This study was undertaken to gain more direct evidence of the pathways and neurochemical mediators of a spinally mediated baroreceptor inhibition of sympathetic preganglionic neurones (SPNs). 2. For this purpose, single-pulse electrical stimulation within identified vasodepressor regions of the nucleus tractus solitarii (NTS) was used together with extracellular recordings of single antidromically identified SPNs in the T2 segment of the spinal cord of anaesthetized rats. 3. The actions of agonists and antagonists of inhibitory amino acids on the NTS-induced inhibitions were determined, when they were iontophoretically applied in the vicinity of SPNs via a multibarrel micropipette assembly. 4. Extracellular recordings were made from sixty-nine SPNs. In forty-four SPNs, NTS stimulation elicited a period of inhibition of activity in both spontaneous and 'D,L-homocysteic acid-driven' SPNs with a latency to onset of 60 + 6 ms and a magnitude of 80 + 3%. 5. In six out of eight neurones, the NTS-induced inhibition was reduced by 74 + 16% during the application of the glycine antagonist strychnine (0-10 nA, 5-10 min) with doses that selectively blocked the inhibitory effect of iontophoretically applied glycine. 6. In nine out of nine neurones, the NTS-induced inhibition was reduced by 38 + 6 % during the application of the GABAA antagonist bicuculline (5-15 nA, 4-14 min) with doses that selectively blocked the inhibitory effect of iontophoretically applied GABA. 7. In two SPNs, the actions of strychnine and bicuculline were shown to be additive in blocking the NTS inhibition. 8. The selective GABAB antagonists,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and CGP 55845A

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Section: Discussionmentioning

confidence: 99%

Chemical mediators of spinal inhibition of rat sympathetic neurones on stimulation in the nucleus tractus solitarii.

Lewis

Coote

1995

The Journal of Physiology

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“…As well as the site in the rostral ventrolateral medulla, long supported as the major location for the inhibitory action of baroreceptors (Seller, 1991), the evidence reported here shows unequivocally that these receptors also activate a pathway which inhibits sympathetic activity at a spinal location. Previous experiments performed to test whether or not baroreceptor inhibition occurs at a spinal site have yielded no more than indirect evidence to suggest it does (Gebber et al 1973;Coote & MacLeod, 1974;Barman & Wurster, 1978;Coote & Westbury, 1979 b). Disfacilitation due to the removal of supraspinal tonic excitatory drive has been the favoured explanation for the reduction in size of a spinal sympathetic response reported in these studies although vigorously denied by some authors (Coote, 1988;Seller, 1991).…”

Section: Discussionmentioning

confidence: 99%

Mediation of baroreceptor inhibition of sympathetic nerve activity via both a brainstem and spinal site in rats.

Lewis

Coote

1994

The Journal of Physiology

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1. The possible involvement of a spinal site of sympatho-inhibitory action in the baroreceptor reflex pathways was investigated by determining the effect of phenylephrine-induced, baroreceptor-mediated inhibition on a spinally evoked excitatory response of renal nerve activity before, during and after removal of tonic descending excitatory drive from the rostral ventrolateral medulla (RVLM). 2. Stimulation of descending excitatory axons at the C4 vertebral level evoked a highly reproducible excitatory response (mean variance, 2'2 + 06%) in a renal sympathetic nerve with a latency of 72 + 5-7 ms and duration of 211 + 32 ms. 3. Following baroreceptor activation, the magnitude of this spinally evoked response was reduced by 33-5 + 4-2% compared with control spinal response. 4. To remove tonic descending excitatory drive, glycine was microinjected bilaterally into the RVLM (RVLM block); this briefly and reversibly abolished spontaneous sympathetic nerve activity. 5. Following RVLM block, the spinally evoked response in a renal sympathetic nerve was inhibited by 16-9 + 4'4 % during baroreceptor activation. 6. Intrathecal administration of the glycine antagonist strychnine to the lower thoracic segments of the spinal cord virtually abolished this inhibition. 7. It was concluded that baroreceptor inhibition of sympathetic activity occurs at a spinal site as well as a supraspinal one. Glycine is a likely mediator of the inhibition at the spinal site.

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“…14,25,26 Somaticnociceptive and autonomic regulatory regions in the central nervous system often respond to the same type of somatic or visceral afferent input. They receive convergent nociceptive and viscerosensory information.…”

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confidence: 99%

Immediate effects of a thoracic spine thrust manipulation on the autonomic nervous system: a randomized clinical trial

Sillevis¹,

Cleland²,

Hellman³

et al. 2010

Journal of Manual & Manipulative Therapy

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Thoracic spine manipulation has been shown to be effective for the management of neck pain. The purpose of this study was to investigate the immediate effect of a T3-T4 spinal thrust manipulation on autonomic nervous system activity in subjects with chronic cervical pain. An additional aim was to determine if the manipulation resulted in an immediate pain relief in patients with chronic neck pain when compared to a placebo intervention. One hundred subjects with chronic neck pain were randomly assigned to receive either a thoracic thrust manipulation or a placebo intervention. The Friedman's test was used to evaluate the change in pupil diameter within both groups. The Wilcoxen signed-ranks test was used to explore pupil changes over time and to make paired comparisons of the pupil change between the groups. The MannWhitney U test was used to compare the change in pain perception for the chronic cervical pain group subjects receiving either the thrust manipulation or the placebo intervention. The results demonstrated that manipulation did not result in a change in sympathetic activity. Additionally, there was no significant difference in the subject's pain perception (P50.961) when comparing the effects of the thrust manipulation to the placebo intervention within this group of subjects with chronic neck pain. The clinical impression of this study is that manipulation of the thoracic spine may not be effective in immediately reducing pain in patients with chronic neck pain.

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Interaction of descending spinal sympathetic pathways and afferent nerves

Cited by 10 publications

References 0 publications

Chemical mediators of spinal inhibition of rat sympathetic neurones on stimulation in the nucleus tractus solitarii.

Chemical mediators of spinal inhibition of rat sympathetic neurones on stimulation in the nucleus tractus solitarii.

Mediation of baroreceptor inhibition of sympathetic nerve activity via both a brainstem and spinal site in rats.

Immediate effects of a thoracic spine thrust manipulation on the autonomic nervous system: a randomized clinical trial

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