Multisegmental spinal sympathetic reflexes originating from the heart

Weaver, Lynne C.; Fry, Hildburg; Meckler, R. L.; Oehl, R. S.

doi:10.1152/ajpregu.1983.245.3.r345

Cited by 13 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although supraspinal neural pathways may participate in these viscerosympathetic reflexes, these reflexes are still differential after spinal cord transection. Previous investigations of the role of supraspinal neural circuitry in the nonuniformity of viscero-sympathetic reflexes have been difficult to interpret, due to the changes in baseline activity of sympathetic nerves produced by spinal cord transection (Weaver et al 1983;Meckler & Weaver, 1985). These baseline problems were avoided in the present study, because the renal and splenic fibres that were still active following spinal cord transection had similar ongoing discharge rates.…”

Section: Discussionmentioning

confidence: 81%

“…For example, stimulation of splenic or cardiac spinal afferent nerves by algogenic chemicals, such as capsaicin and bradykinin, causes greater increases in firing of multifibre splenic nerves than of renal sympathetic nerves (Weaver, Fry, Meckler & Oehl, 1983;Calaresu, Tobey, Heidemann & Weaver, 1984). Cardiovascular pressoreceptor stimulation also causes unequal responses of multifibre splenic and renal nerves (Tobey & Weaver, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…Much of our current understanding of fractionated sympathetic control of the circulation is based on experiments in which electrical discharge has been recorded R. L. MECKLER AND L. C. WEA VER from whole nerves innervating different organs (Karim, Kidd, Malpus & Penna, 1972;Weaver, Fry & Meckler, 1984). For example, stimulation of splenic or cardiac spinal afferent nerves by algogenic chemicals, such as capsaicin and bradykinin, causes greater increases in firing of multifibre splenic nerves than of renal sympathetic nerves (Weaver, Fry, Meckler & Oehl, 1983;Calaresu, Tobey, Heidemann & Weaver, 1984). Cardiovascular pressoreceptor stimulation also causes unequal responses of multifibre splenic and renal nerves (Tobey & Weaver, 1987).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characteristics of ongoing and reflex discharge of single splenic and renal sympathetic postganglionic fibres in cats.

Meckler

Weaver

1988

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Electrical discharge of thirty-nine single splenic and renal postganglionic nerve fibres was recorded in artificially respired, chloralose-anaesthetized cats.2. Ongoing discharge rates, averaged over 10 s periods, did not differ between renal and splenic fibres. All neurones of both groups had irregular discharge frequencies.3. Half of the splenic population and all renal fibres had cardiac-related discharge patterns. Of those tested for respiratory-related firing, 30 % of the splenic fibres and 69% of the renal fibres exhibited this pattern.4. Firing of splenic fibres was less inhibited than that of renal fibres by stimulation of pressoreceptors with phenylephrine-induced increases in blood pressure. Firing of splenic fibres also was less excited than that of renal fibres by unloading pressoreceptors with depressor doses of sodium nitroprusside.5. Chemical stimulation of splenic afferent nerves with bradykinin consistently elicited greater increases in splenic than renal nerve discharge by causing large increases in firing of all splenic fibres and smaller excitatory responses in 75 % of the renal fibres.6. Application of bradykinin to the intestinal serosa produced greater increases in renal than splenic nerve discharge by consistently causing increased firing of renal fibres and by causing excitation, inhibition, or no change in splenic fibre discharge.7. Responses of splenic and renal fibres to stimulation of splenic and intestinal afferent nerves after spinal cord transection were similar to those responses elicited when the neuraxis was intact.8. In conclusion, the differerntial reflex responses of splenic and renal neuronal populations can be due to the heterogeneity or to the intensity of responses within a neuronal population.

show abstract

Section: Discussionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characteristics of ongoing and reflex discharge of single splenic and renal sympathetic postganglionic fibres in cats.

Meckler

Weaver

1988

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…Considering the first of these possible mechanisms, many studies have shown that activation of cardiac "sympathetic afferents", by electrical stimulation of these afferent fibers (26,31,46) or by chemical stimuli such as bradykinin (45,46), or coronary occlusion (13), has sympathoexcitatory effects. Those excitatory effects may be enhanced or unmasked by vagotomy (14,31).…”

Section: Discussionmentioning

confidence: 99%

Nonuniformity in the von Bezold-Jarisch reflex

Salo¹,

Woods²,

Anderson³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

The von Bezold-Jarisch reflex (BJR) is a vagally mediated chemoreflex from the heart and lungs, causing hypopnea, bradycardia, and inhibition of sympathetic vasomotor tone. However, cardiac sympathetic nerve activity (CSNA) has not been systematically compared with vasomotor activity during the BJR. In 11 urethane-anesthetized (1-1.5 g/kg iv), artificially ventilated rats, we measured CSNA simultaneously with lumbar sympathetic activity (LSNA) while the BJR was evoked by right atrial bolus injections of phenylbiguanide (0.5, 1.0, 1.5, and 2 microg). Nerve and heartbeat responses were analyzed by calculating normalized cumulative sums. LSNA and heartbeats were always reduced by the BJR. An excitatory "rebound" component often followed the inhibition of LSNA but never outweighed it. For CSNA, however, excitation usually (in 7 of 11 rats) outweighed any initial inhibition, such that the net response to phenylbiguanide was excitatory. The differences in net response between LSNA, CSNA, and heartbeats were all significant (P < 0.01). A second experimental series on seven rats showed that methyl atropine (1 mg/kg iv) abolished the bradycardia of the BJR, whereas subsequent bilateral vagotomy substantially reduced LSNA and CSNA responses, both excitatory and inhibitory. These findings show that, during the BJR, 1) CSNA is often excited, 2) there may be coactivation of sympathetic and parasympathetic drives to the heart, 3) divergent responses may be evoked simultaneously in cardiac vagal, cardiac sympathetic, and vasomotor nervous pathways, and 4) those divergent responses are mediated primarily by the vagi.

show abstract

“…A previous investigation in this laboratory demonstrated that sympathoexcitatory responses to chemical stimulation of cardiac afferent nerves can be mediated by exclusively spinal neural circuits (Weaver, Fry, Meckler & Oehl, 1983). A third objective of this investigation was to determine the extent to which the responses to intestinal receptor stimulation depend upon supraspinal pathways, by administering bradykinin prior to, and 1 h following, a cervical spinal cord transection.…”

Section: Introductionmentioning

confidence: 99%

Multi‐ and single‐fibre mesenteric and renal sympathetic responses to chemical stimulation of intestinal receptors in cats.

Stein

Weaver

1988

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. In cats anaesthetized with a-chloralose and artificially respired, stimulation of intestinal receptors with bradykinin caused greater reflex excitation of mesenteric than of renal efferent multifibre nerve activity and significant pressor responses.2. Activity of all nerve bundles used in this study was inhibited by stimulation of pressoreceptors. Increases in systemic arterial pressure caused inhibition of activity of renal nerves which was significantly greater than that of mesenteric nerves.3. Spinal transection caused significant decreases in tonic renal nerve activity without altering the ongoing discharge rate of mesenteric nerves. Stimulation of intestinal receptors in spinal cats still caused significant increases in discharge of mesenteric and renal nerves, indicating that this reflex contains a spinal component.4. Recordings of activity of individual fibres within mesenteric (21) and renal (23) nerves provided information regarding the basis for the multifibre responses to stimulation of intestinal receptors. The same proportion of fibres from both nerves was excited, but the increase in activity of mesenteric fibres was significantly greater than that of renal fibres.5. Mesenteric fibres could be classified into two groups, based on their sensitivity to pressoreceptor influences. Fibres that exhibited pressoreceptor-independent discharge had the greatest responses to stimulation of intestinal receptors.6. Following spinal transection the majority of mesenteric fibres continued to fire, whereas most renal fibres became quiescent.7. The non-uniform pattern of neuronal excitation to chemical stimulation of intestinal receptors was manifest after spinal transection, demonstrating that exclusively spinal pathways can mediate this differential response pattern.8. These results support the hypothesis that viscero-sympathetic reflexes may be organized to cause preferential excitation of neural activity directed to the organ from which the reflex originates.

show abstract

Multisegmental spinal sympathetic reflexes originating from the heart

Cited by 13 publications

References 0 publications

Characteristics of ongoing and reflex discharge of single splenic and renal sympathetic postganglionic fibres in cats.

Characteristics of ongoing and reflex discharge of single splenic and renal sympathetic postganglionic fibres in cats.

Nonuniformity in the von Bezold-Jarisch reflex

Multi‐ and single‐fibre mesenteric and renal sympathetic responses to chemical stimulation of intestinal receptors in cats.

Contact Info

Product

Resources

About