Spinal entry route for ventral root afferent fibers in the cat

Hong Kee Shin, Jun Kim, Sang Chae Nam, Kwang Se Paik, Jin Chung

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Twelve anesthetized and paralyzed cats were used to study the spinal entry routes of ventral root afferent fibers. In all animals, the spinal cord was transected at two different levels, L5 and S2. The L5 through S2 dorsal roots were cut bilaterally, making spinal cord segments L5-S2 neurally isolated from the body except for the L5-S2 ventral roots. From this preparation, a powerful excitation of the discharge rate of motor neurons and dorsal horn cells within the isolated spinal segments was observed after intraarterial injection of bradykinin (50 μg in 0.5 ml saline). This excitation of the spinal neurons can be considered the most convincing evidence of the potential physiologic role of the ventral root afferent fibers entering the spinal cord directly through the ventral root, because the apparent route of neuronal input from the periphery is through the ventral roots. However, additional control experiments conducted in the present study showed that the excitation persisted even after cutting all ventral roots within the isolated spinal segments, indicating that excitation was not mediated by the ventral roots. Furthermore, direct application of bradykinin on the dorsal surface of the spinal cord also increased the motoneuronal discharge rate, suggesting that excitation of spinal neurons produced by intraarterial injection of bradykinin is due to a direct action of bradykinin on the spinal cord. Thus, we provided an alternate explanation for the most convincing evidence indicating that physiologically important ventral root afferent fibers enter the spinal cord directly through the ventral root. Based on existing experimental evidence, it is likely that the majority of physiologically active ventral root afferent fibers travel distally toward the dorsal root ganglion and then enter the spinal cord through the dorsal root.

Original languageEnglish (US)
Pages (from-to)714-725
Number of pages12
JournalExperimental Neurology
Volume94
Issue number3
DOIs
StatePublished - 1986

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Spinal Nerve Roots
Cats
Spinal Cord
Bradykinin
Intra-Arterial Injections
Posterior Horn Cells
Neurons
Spinal Ganglia
Motor Neurons

ASJC Scopus subject areas

  • Neuroscience(all)
  • Neurology

Cite this

Spinal entry route for ventral root afferent fibers in the cat. / Shin, Hong Kee; Kim, Jun; Nam, Sang Chae; Paik, Kwang Se; Chung, Jin.

In: Experimental Neurology, Vol. 94, No. 3, 1986, p. 714-725.

Research output: Contribution to journalArticle

Shin, Hong Kee ; Kim, Jun ; Nam, Sang Chae ; Paik, Kwang Se ; Chung, Jin. / Spinal entry route for ventral root afferent fibers in the cat. In: Experimental Neurology. 1986 ; Vol. 94, No. 3. pp. 714-725.
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