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

Davies, W. I. R.; Scott, Donald M.; Vesterstrøm, K.; Vyklicky, Ladislav

doi:10.1113/jphysiol.1971.sp009631

Cited by 66 publications

(4 citation statements)

References 16 publications

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“…Although the present findings of the tooth pulp afferent projection patterns in the trigeminal sensory nucleus are consistent with previous anatomic (see references in the introductory section) and electrophysiological studies (Davies et al, 1971;Yokota, 1975;Greenwood and Sessle, 1976;Sessle and Greenwood, 1976;Shigenaga et al, 1976;Vyklicky et al, 1977;Woda et al, 1977;Dawson et al, 1980;Azerad et al, 1982;Dostrovski, 1984), we have documented that their synaptic organization differs among the nuclei. It is well known that the tooth pulp is innervated by A-delta fibers that form a nerve plexus beneath the predentin and by unmyelinated (C-fiber) primary afferents that distribute around the center of tooth pulp (Sessle, 1987;Narhi, 1990;Narhi et al, 1994).…”

Section: Synaptic Organization Of Tooth Pulp Afferent Terminals In Trsupporting

confidence: 89%

Synaptic organization of tooth pulp afferent terminals in the rat trigeminal sensory nuclei

Bae

Kim

Choi

et al. 2003

J of Comparative Neurology

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Previous studies provide evidence that a structure/function correlation exists in the distinct zones of the trigeminal sensory nuclei. To evaluate this relationship, we examined the ultrastructure of afferent terminals from the tooth pulp in the rat trigeminal sensory nuclei: the principalis (Vp), the dorsomedial part of oral nucleus (Vdm), and the superficial layers of caudalis (Vc), by using transganglionic transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). A total of 93 labeled boutons were serially sectioned, in which some sections were incubated with gamma-aminobutyric acid (GABA) antiserum. Almost all labeled boutons formed asymmetric contact with nonprimary dendrites, in which more than half of labeled boutons in the Vc made synapses with their spines. The labeled boutons could be divided into two types on the basis of numbers of dense-cored vesicles (DCVs) in a boutons: S-type and DCV-type. Almost all labeled boutons in the Vp and Vdm were S-type, whereas two types were distributed evenly in the Vc. In contrast to DCV-type boutons, the S-type was frequently postsynaptic to unlabeled axon terminals containing a mixture of round, oval, and flattened vesicles (p-endings) and forming symmetrical synapses. Most p-endings examined were immunoreactive to GABA. The frequency of axoaxonic contacts was higher for labeled boutons in the Vp than in the Vdm and Vc. These results suggest that the three structures of trigeminal sensory nuclei serve distinct functions in nociceptive processing.

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Section: Synaptic Organization Of Tooth Pulp Afferent Terminals In Trsupporting

confidence: 89%

Synaptic organization of tooth pulp afferent terminals in the rat trigeminal sensory nuclei

Bae

Kim

Choi

et al. 2003

J of Comparative Neurology

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“…The conduction velocity of tooth pulp afferents lies primarily within the A␦ range (Davies et al, 1971;Lisney, 1979;Dostrovsky et al, 1981;Cairns et al, 1996). The present results indicate that the magnitude of TGT neuronal responses to tooth pulp stimulation is suppressed during AS.…”

Section: State-dependent Changes In Peripherally Evoked Responsessupporting

confidence: 48%

Spontaneous Discharge and Peripherally Evoked Orofacial Responses of Trigemino–Thalamic Tract Neurons during Wakefulness and Sleep

et al. 1996

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In the present study, ongoing and evoked activity of antidromically identified trigemino-thalamic tract (TGT) neurons was examined over the sleep-wake cycle in cats. There was no difference in the mean spike discharge rate of TGT neurons when quiet sleep (QS) and active sleep (AS) were compared with wakefulness (W). However, tooth pulp-evoked responses of TGT neurons were decreased during AS when compared to W. Conversely, the responses of TGT neurons to air puff activation of facial hair mechanoreceptors reciprocally increased during AS when compared to W. The present data demonstrate that ascending sensory information emanating from distinct orofacial areas is differentially modified during the behavioral state of AS. Specifically, the results obtained suggest that during AS, sensory information arising from hair mechanoreceptors is enhanced, whereas information arising from tooth pulp afferents is suppressed. These data may provide functional evidence for an AS-related gate control mechanism of sensory outflow to higher brain centers. Key words: behavioral state; brainstem; hair mechanoreceptor; main sensory nucleus; nucleus oralis; sensory; sleep; tooth pulp; trigeminothalamicThe trigemino-thalamic tract (TGT) is a major somatosensory pathway that conveys sensory information from orofacial regions rostrally to the thalamus and on to the cerebral cortex. Both electrophysiological (Sessle and Greenwood, 1976;Sessle and Hu, 1981;Azerad et al., 1982;Sunada et al., 1990;Ro and Capra, 1994) and anatomical labeling (Mizuno, 1970;Woda et al., 1977;Burton and Craig, 1979;Matsushita et al., 1982;Shigenaga et al., 1986;Matthews et al., 1987Matthews et al., , 1989) studies performed in acute anesthetized cats have demonstrated that the rostral trigeminal sensory nuclear complex (TSNC) comprising, respectively, the nucleus oralis and the main sensory nucleus, contains a high density of TGT neurons. Recently, we have shown that the tooth pulp-evoked activity of rostral TSNC neurons is suppressed specifically during the behavioral state of active (AS) or REM sleep . However, the axonal projection of the recorded cells was not determined.Given the high density of TGT neurons located in the rostral TSNC in concert with our recent findings of AS-related suppression of these neurons, we hypothesize that synaptic transmission via the TGT is suppressed during the behavioral state of AS. To test this hypothesis, the present study was performed to identify TGT neurons and measure their ongoing and peripherally evoked activity recorded during sleep and wakefulness in chronically instrumented behaving cats. The results obtained via stimuli applied to tooth pulp afferents versus facial hair mechanoreceptors suggest that the source of the peripheral input used to activate the recorded neurons is critical in determining the active sleep-related changes that occur in synaptic transmission through the TGT.

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“…The orthodromic response, recorded bipolarly, was largest in amplitude in, or in the vicinity of, the subnucleus oralis of the spinal tract nucleus. In agreement with Davies et al (1971), the latency and duration of the response were about 2.0 and 5.0 msec, respectively.…”

Section: Resultssupporting

confidence: 83%

Presynaptic Inhibition of Tooth Pulp Afferents in the Trigeminal Nucleus During REM Sleep

Satoh

Harada

Watabe

et al. 1980

Sleep

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In order to find whether presynaptic inhibition of tooth pulp afferents is enhanced in any phase of sleep or wakefulness, the orthodromic mass response of the trigeminal nucleus to electrical stimulation of the ipsilateral tooth pulp and the antidromic mass response of the tooth pulp to stimulation of the trigeminal nucleus were recorded in the cat. Both responses were stable in amplitude during different phases of sleep and wakefulness, However, attenuation of the orthodromic response and augmentation of the antidromic one were sometimes observed during the burst of rapid eye movements during paradoxical sleep, suggesting that presynaptic inhibition is massively enhanced only on those occasions,

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

Cited by 66 publications

References 16 publications

Synaptic organization of tooth pulp afferent terminals in the rat trigeminal sensory nuclei

Synaptic organization of tooth pulp afferent terminals in the rat trigeminal sensory nuclei

Spontaneous Discharge and Peripherally Evoked Orofacial Responses of Trigemino–Thalamic Tract Neurons during Wakefulness and Sleep

Presynaptic Inhibition of Tooth Pulp Afferents in the Trigeminal Nucleus During REM Sleep

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