The sacral levels contributing afferent fibers to the feline pelvic and pudendal nerves: Verifications by silver impregnation of degenerating axons after dorsal root ganglionectomy

1957 ◽  
Vol 128 (3) ◽  
pp. 401-409 ◽  
Author(s):  
R. James Seymour ◽  
James B. Campbell
Keyword(s):  
Dorsal Root ◽  
Silver Impregnation ◽  
Afferent Fibers ◽  
Degenerating Axons

Sympathetic Influence on Capsaicin-Evoked Enhancement of Dorsal Root Reflexes in Rats

2004 ◽  
Vol 92 (4) ◽  
pp. 2017-2026 ◽  
Author(s):  
Jing Wang ◽  
Yong Ren ◽  
Xiaoju Zou ◽  
Li Fang ◽  
William D. Willis ◽  
...  
Keyword(s):  
Dorsal Root ◽  
Neurogenic Inflammation ◽  
Intradermal Injection ◽  
Primary Afferent ◽  
Adrenoceptor Antagonist ◽  
Afferent Fibers ◽  
Adrenoceptor Agonist ◽  
Sympathetic Modulation ◽  
Sympathetic Influence ◽  
Series Of Experiments

A series of experiments by our group suggest that the initiation and development of neurogenic inflammation in rats are mainly mediated by dorsal root reflexes (DRRs), which are conducted centrifugally from the spinal dorsal horn in primary afferent nocieptors. In this study, DRRs were recorded in anesthetized rats from single afferent fibers in the proximal ends of cut dorsal root filaments at the L4–L6 level and tested for responses to intradermal injection of capsaicin. Sympathectomy combined with pharmacological manipulations were employed to determine if the capsaicin-evoked enhancement of DRRs was subject to sympathetic modulation. DRRs could be recorded from both myelinated (Aβ and Aδ) and unmyelinated (C) afferent fibers. After capsaicin was injected intradermally into the plantar foot, a significant enhancement of DRRs was seen in C- and Aδ-fibers but not in Aβ-fibers. This enhancement of DRRs evoked by capsaicin injection was almost completely prevented by sympathectomy. However, if peripheral α1-adrenoceptors were activated by intra-arterial injection of phenylephrine, the enhancement of DRRs evoked by capsaicin could be restored, whereas no such restoration was seen following pretreatment with an α2-adrenoceptor agonist, UK14,304. Under sympathetically intact conditions, the enhanced DRRs following capsaicin injection could be blocked by administration of terazosin, an α1-adrenoceptor antagonist, but not by administration of yohimbine, an α2-adrenoceptor antagonist. These results provide further evidence that the DRR-mediated neurogenic inflammation depends in part on intact sympathetic efferents acting on peripheral α1-adrenoceptors, which augment the sensitization of primary afferent nociceptors induced by capsaicin injection, helping trigger DRRs that produce vasodilation.

Effect of dorsal root section on the arrhythmias associated with coronary occlusion

1976 ◽  
Vol 231 (3) ◽  
pp. 923-928 ◽  
Author(s):  
PJ Schwartz ◽  
RD Foreman ◽  
HL Stone ◽  
AM Brown
Keyword(s):  
Coronary Artery ◽  
Dorsal Root ◽  
Coronary Occlusion ◽  
Absolute Number ◽  
Root Section ◽  
Dorsal Roots ◽  
Somatic Afferents ◽  
Afferent Fibers ◽  
Surgical Preparation ◽  
Ectopic Beats

In anesthetized vagotomized dogs and cats the circumflex and/or the anterior descending coronary artery were briefly occluded (5-90 s), and ectopic beats occurring during the occlusion and for 60 s following release were counted. When arrhythmias were regularly produced for a given occlusion, the dorsal roots from C8 to T5 were transected and the occlusions were repeated. Dorsal root section produced minor changes in heart rate and blood pressure. Dogs and cats did not differ in their responses. Dorsal root section was performed in eight animals and decreased the absolute number of ectopic beats by 63 +/- 19% compared to control values (P less than 0.05). In four animals the effect on ectopic beats produced by repeated occlusions without dorsal root section was investigated and found to be increased by 35 +/- 24% compared to contrl values. Most of the somatic afferents contained in the dorsal roots were damaged by the surgical preparation. Therefore, repeated occlusions and interruption of somatic afferents do not appear to have influenced our results. The arrhythmogenic interaction between the local effects of myocardial ischemia and the sympathetic activity, whose outlow contained in the ventral roots remained intact, was still possible after dorsal root section and this explains why ectopic beats were reduced but not almost suppressed as is usually the case after bilateral stellectomy. We conclude that dorsal root section reduces the number of ectopic beats associated with short-lasting coronary artery occlusions and that the most likely mechanism is the interruption of the cardiocardiac sympathetic reflex which depends upon afferent fibers running through the dorsal roots.

Microsurgical DREZ-otomy for the Treatment of Spasticity and Pain in the Lower Limbs

Neurosurgery ◽  
1989 ◽  
Vol 24 (5) ◽  
pp. 655-670 ◽  
Author(s):  
Marc Sindou ◽  
Daniel Jeanmonod
Keyword(s):  
Dorsal Root ◽  
Lower Limbs ◽  
Lateral Part ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Root Entry Zone ◽  
Afferent Fibers ◽  
Disabled Patients

ABSTRACT The authors report on a series of 53 bedridden patients suffering from harmful spasticity in one (6) or both (47) lower limbs, who were treated with microsurgical DREZ-otomy. Surgery was performed to treat fixed abnormal postures in flexion in 49 patients and hyperextension in 3, and, additionally, to treat pain in 37 patients. Microsurgical DREZ-otomy was introduced in 1972, on the basis of anatomical studies of the human dorsal root entry zone (DREZ) showing a topographical segregation of the afferent fibers according to their size and functional destinations. It consists of a 2 mm deep microsurgical lesion directed at a 45° angle in the posterolateral sulcus and penetrating the dorsal root entry zone in its ventrolateral aspect, at the level of all the rootlets considered involved in spasticity (and pain). It destroys mainly the lateral (nociceptive) and central (myotatic) afferent fibers as well as the facilitatory medial part of the Lissauer tract, while sparing most of the medial (lemniscal) fibers, the suppressor lateral part of the Lissauer tract, and more or less of the dorsal horn (DH). The postoperative results were evaluated after a mean follow-up period of 3 years and 4 months. Both spasticity and spasms were significantly decreased or suppressed in 75% and 88.2% of the patients, respectively. When present, pain was relieved without abolition of sensation in 91.6%. These benefits-combined with complementary orthopedic surgery in 23 patients-resulted in either disappearance or marked reduction of the abnormal postures in 85.3% of the patients and of articular limitations in 96.8%. Mid-to-severe complications occurred in 25 patients and precipitated or were responsible for death in 5. This is explained by the fact that the general and neurological conditions of most of the patients-especially those affected by multiple sclerosis-were precarious. MDT has, however, enabled a majority of these severely disabled patients to sit and lie comfortably, and has allowed them to reach a significantly improved quality of life.

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