Functional Characteristics of Afferent Fibers From Tooth Pulp of Cat

Brookhart, John M.; Livingston, W. K.; Haugen, Frederick P.

doi:10.1152/jn.1953.16.6.634

Cited by 135 publications

(18 citation statements)

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“…These results are con sistent with the observations that the reflex jaw opening in the cat was induced not only from the lowest threshold fibers in the trigeminal nerve (Aa fibers) (1, 3, 4), but also from Ad fibers (6, 7) containing the tooth pulp (2, 5) which consists exclusively of the small my elinated fibers of 1-7 ,u in diameter (Ay-d fibers) (8).…”

Section: Two Components Of the Jaw Opening Reflexsupporting

confidence: 87%

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Effect of Fentanyl, A Narcotic Analgesic, on Two Components of the Jaw Opening Reflex

Nishijima

Sakai

1975

Japanese Journal of Pharmacology

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Abstract--An action of fentanyl, a short-acting narcotic, on the reflex discharge in the digastric nerve induced by the inferior alveolar nerve stimulation was investigated in a-chloralose anesthetized cats. In the ipsilateral digastric reflex discharge, there were an early phase induced by stimulus exciting Aa fibers and a late phase appearing when A5 fibers were also stimulated. Following dorso-lateral cordotomy at the obex level, an isolation of the spinal trigeminal nucleus caudalis, a total area in the digastric reflex discharge decreased, while its first peak amplitude was little affected, indicating a disappearance of the late phase and a preservation of the early phase. Fentanyl depressed both the total discharge area and the first peak amplitude. After dorso lateral cordotomy, the depression of the area decreased considerably, whereas that of the amplitude decreased slightly. Results indicate that fentanyl depressed both the early phase which is activated by the Aa fiber stimulation, not via the subnucleus caudalis and the late phase which is activated by the Ab fiber stimulation via the sub nucleus caudalis or its surroundings.The latter action would be related to the anal gesic action of fentanyl.It is known that the jaw opening in the cat, as seen by digastric muscle con traction, can be reflexly elicited by the excitation of the second or third branches of the trigeminal nerve (1-7). Responsible afferent limbs are low threshold afferents of Group II range size (Ad.) (l, 3, 4, 7) and those of Group Ill (Ad) (2, 5-7). Analgesics such as morphine increased the threshold for this reflex to the stimulation of tooth pulp, which consists exclusively of Ay-o fibers in cats (8), and this action was implicated in drug ac tion to alleviate the pain, though direct proof on an analgesic effect has not been demon strated (2). Following unilateral hemisection at C, level, which is known to cause ipsilateral facial analgesia in man (Sjdgvist operation) (9), Riblet and Mitchell (10) found that the tooth pulp threshold on the ipsilateral side for eliciting the jaw opening reflex in the cat elevated and concurrently, morphine became less effective, and suggested that morphine may exert its depressant effect through actions on the subnucleus caudalis of the spinal trigeminal nucleus. However, the digastric reflex discharge induced by the inferior alveolar nerve stimulation was not totally affected by the transection of the spinal tract and the spinal tract nucleus at the level of the obex (11). Therefore, it is likely that the digastric reflexes induced by volleys in different afferent fiber components pass through different pathways and have different drug sensibilities within the brain stem and upper spinal cord.In the present investigation, we studied an action of a narcotic on the trigeminal sys

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Section: Two Components Of the Jaw Opening Reflexsupporting

confidence: 87%

“…(l, 3, 4, 7) and those of Group Ill (Ad) (2,(5)(6)(7). Analgesics such as morphine increased the threshold for this reflex to the stimulation of tooth pulp, which consists exclusively of Ay-o fibers in cats (8), and this action was implicated in drug ac tion to alleviate the pain, though direct proof on an analgesic effect has not been demon strated (2).…”

mentioning

confidence: 99%

Effect of Fentanyl, A Narcotic Analgesic, on Two Components of the Jaw Opening Reflex

Nishijima

Sakai

1975

Japanese Journal of Pharmacology

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“…4A), while action potentials of longer latency contributing to the formation of the latter parts of the complex antidromic potentials did not appear until higher intensity of the stimulus was used (Fig. 4B, C Brookhart et al (1953). We are uncertain about the conduction velocity of the slowest afferent fibres, but from latencies of individual components of the antidromic potential, it seems likely to be less than half that obtained for the fastest fibres.…”

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confidence: 87%

Depolarization of the tooth pulp afferent terminals in the brain stem of the cat

Davies¹,

Scott²,

Vesterstrøm³

et al. 1971

The Journal of Physiology

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SUMMARY1. Tooth pulp afferent fibres belonging exclusively to the AA group were stimulated bi-polarly with electrical pulses applied to the dentine and the central effects of the stimulation were examined in the nucleus of the spinal trigeminal complex of anaesthetized cats.2. Field potentials evoked by single pulses to the upper or lower canine tooth pulp were explored over the nucleus of the spinal trigeminal tract in the region 5 mm caudally to the obex up to 8-5 mm rostrally to the obex. They were found to be restricted to a region of 5-5-8-5 mm rostrally to the obex, 4-5 mm laterally from the mid line, with a maximum amplitude at a depth of 5+ 0-5 mm.3. Antidromic action potentials were recorded from the tooth pulp afferents. The stimulating micro-electrode was inserted in the region of the medulla from which distinct field potentials could be recorded by orthodromic stimulation.4. Excitability of the central terminals of the tooth pulp primary afferents was increased when the test stimulus was preceded either by a conditioning volley in low threshold afferent fibres of the infraorbital nerve or in Ad fibres of another tooth.5. Single pulses applied to the afferent fibres of the tooth pulp produced changes in the excitability of central terminals of the fast conducting afferent fibres of the infraorbital nerve.6. The greatly increased excitability of central terminals of tooth pulp primary afferent fibres was accompanied by a small decrease in their

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“…The trigeminal sensory system differs from spinal somatic afferents in several ways. Amongst these are the exceptionally high density of innervation of the face area (Darian-Smith, Mutton & Proctor, 1965), which is reflected in the large representation of the face in the sensory cortex (Darian-Smith, Ibister, Mok & Yokota, 1966); the unique sensory properties of the vibrissae (Zucker & Welcker, 1969;Pubols, Donovick & Pubols, 1973) and the dental pulp (Brookhart, Livingston & Haugen, 1953;Anderson, Hannam & Matthews, 1970); and the unique anatomical and physiological properties of the trigeminal sensory nuclei in the brainstem and spinal cord (Olzewski, 1950;Wall & Taub, 1962). In the preceding study, the general localization and overall pattern of CF projection from trigeminal cutaneous afferents and the SI cortex was described, using electrical stimulation of nerve trunks and laminar field potential analysis (Miles & Wiesendanger, 1975).…”

mentioning

confidence: 99%

Climbing fibre inputs to cerebellar Purkinje cells from trigeminal cutaneous afferents and the SI face area of the cerebral cortex in the cat.

Miles¹,

Wiesendanger²

1975

The Journal of Physiology

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Functional Characteristics of Afferent Fibers From Tooth Pulp of Cat

Cited by 135 publications

References 0 publications

Effect of Fentanyl, A Narcotic Analgesic, on Two Components of the Jaw Opening Reflex

Effect of Fentanyl, A Narcotic Analgesic, on Two Components of the Jaw Opening Reflex

Depolarization of the tooth pulp afferent terminals in the brain stem of the cat

Climbing fibre inputs to cerebellar Purkinje cells from trigeminal cutaneous afferents and the SI face area of the cerebral cortex in the cat.

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