Synaptic structures and quantification of catecholaminergic axons in the nucleus tractus solitarius of the rat: Possible modulatory roles of catecholamines in baroreceptor reflexes

Chiba, Tetsuhiro; Kato, Makoto

doi:10.1016/0006-8993(78)90888-0

Cited by 43 publications

(13 citation statements)

References 36 publications

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“…Most of the published ultrastructural descriptions of the caudal NTS concern its medial, dorsomedial, and commissural subdivisions Doba, 1975,1976;Chiba and &to, 1978;Takahashi et al, 1980;Leslie et al, 1982;Rinaman et al, 19891, regions implicated in cardiovascular and gastrointestinal processing. Recent reports have also dealt with the morphology of the ventral and ventrolateral subdivisions relceivingpulmonary afferents .…”

Section: Indexing Terms: Dorsal Vagal Complex Vagus Nerve Electron mentioning

confidence: 98%

Synaptic organization of the interstitial subdivision of the nucleus tractus solitarii and of its laryngeal afferents in the rat

Mrini¹,

Jean²

1995

J of Comparative Neurology

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The nucleus tractus solitarii, the first central relay for gustatory and a variety of visceral afferents, is also an integrative center for numerous functions. Its interstitial subdivision is involved in swallowing and respiratory reflexes. The ultrastructural characteristics of this subdivision and of its laryngeal afferents were investigated in adult rat by a serial-section study and by application of wheat germ agglutinin-horseradish peroxidase conjugate to the peripheral afferent fibers. The interstitial subnucleus contained scattered small neuronal cell bodies with such ultrastructural features as a large nucleus with deep indentations and an organelle-poor cytoplasm. On the basis of their size and vesicular content, the axon terminals were classified into three categories. Group I and group II terminals were small or large, respectively, and contained mainly small, round, and clear synaptic vesicles. Group III terminals were also small but contained small, pleomorphic, and clear vesicles. Axodendritic synapses were the most numerous. They were either asymmetrical, comprised of group I and II terminals, or symmetrical, comprised of group III terminals. More than 50% were part of complex synaptic arrangements in the form of rosettes or glomeruli. Axosomatic contacts involved both group I and group III terminals and were always symmetrical. A high frequency of axoaxonic synapses was found. They were symmetrical, comprised of group III terminals on group I or II terminals. Different types of symmetrical synaptic contacts made by dendrites were also found. This study indicates also that the ipsilateral interstitial subdivision constitutes the preferential site of termination for superior laryngeal afferents. The labeled axon terminals belonged exclusively to groups I and II and were involved in both axodendritic and axoaxonic synapses. Some of the axodendritic synapses were part of rosettes or glomeruli. All these synaptic arrangements may be considered a morphological substrate for important processing of afferent information in the nucleus tractus solitarii. They may account for some of the integrative functions of the interstitial subnucleus such as physiological processes triggered from the superior laryngeal nerve.

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Section: Indexing Terms: Dorsal Vagal Complex Vagus Nerve Electron mentioning

confidence: 98%

Synaptic organization of the interstitial subdivision of the nucleus tractus solitarii and of its laryngeal afferents in the rat

Mrini¹,

Jean²

1995

J of Comparative Neurology

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“…type have widely arborizing, spiny dendritic trees, and since it has been shown by several authors (Rall et al 1967;Jack, Redman & Wong, 1981) (Curtis, Hdsli, Johnston & Johnston, 1968;Krnjevic, Puil & Werman, 1977) (Champagnat et al 1985b;Miles, 1985), possibly that of presynaptic inhibition of some visceral afferents by others via axo-axonic synapses existing in the n.t.s. (Chiba & Kato, 1978).…”

Section: Organization Of the Solitary Complex Discussionmentioning

confidence: 99%

Organization of synaptic transmission in the mammalian solitary complex, studied in vitro.

Champagnat¹,

Denavit-Saubié²,

Grant³

et al. 1986

The Journal of Physiology

101

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SUMMARY1. Synaptic transmission and neuronal morphology were studied in the nucleus tractus solitarius and in the dorsal vagal motor nucleus (solitary complex), in coronal brain-stem slices of rat or cat, superfused in vitro.2. Electrical stimulation of afferent fibres of the solitary tract evoked two different types of post-synaptic response recorded intracellularly in different solitary complex neurones. Labelling with horseradish peroxidase showed that these two sorts of orthodromically evoked responses were correlated with different post-synaptic neuronal morphologies.3. The majority of recorded neurones (n = 93) showed a prolonged reduction in excitability following the initial solitary-tract-evoked excitatory post-synaptic potential (e.p.s.p.). A smaller number of neurones (n = 53) showed a prolonged increase in excitability following solitary tract stimulation. In no case did the solitary tract stimulation induce a burst of action potentials at high frequency.4. The time-to-peak and the half-width of the initial solitary-tract-evoked e.p.s.p. were shorter in neurones with prolonged increased excitability than in those with prolonged reduced excitability. In neurones with prolonged reduced excitability, this e.p.s.p. was followed by a hyperpolarization lasting 60-100 ms. The latency of this inhibitory post-synaptic potential (i.p.s.p.) was 3-5 ms longer than that of the initial e.p.s.p. and its reversal potential was 10 mV more negative than the reversal potential of the response measured following application of y-aminobutyric acid or glycine. In neurones with prolonged increased excitability, at a membrane potential of -40 to -50 mV, the initial solitary tract e.p.s.p. was followed by a prolonged depolarization lasting 100-400 ms.5. Background synaptic activity was high in neurones with prolonged increased excitability, consisting of unitary e.p.s.p.s with an amplitude of more than 0-8 mV. This activity was increased for a period of 300-800 ms following solitary tract stimulation. Spontaneous excitatory potentials of more than 0-5 mV were not seen in neurones with prolonged reduced excitability. In these neurones, after intracellular injection of choride ions, reversed unitary i

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“…The location of CA neurons amid the terminal fields of visceral afferents led to a general assumption that NTS CA neurons broadly integrate afferent information and relay it to multiple brain regions via their extensive projections (Chiba and Kato, 1978;Takahashi et al, 1979;Kalia et al, 1985a,b;Mtui et al, 1995). Activation of afferents from gastrointestinal, cardiovascular, and respiratory targets supported widespread stimulation of CA NTS neurons in various behaviors including sleep and stress (Murphy et al, 1994;Chan and Sawchenko, 1998;Dayas et al, 2004;Kubin et al, 2006).…”

Section: Visceral Integration and Nts Ca Neuronsmentioning

confidence: 99%

Visceral Afferents Directly Activate Catecholamine Neurons in the Solitary Tract Nucleus

et al. 2007

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Synaptic structures and quantification of catecholaminergic axons in the nucleus tractus solitarius of the rat: Possible modulatory roles of catecholamines in baroreceptor reflexes

Cited by 43 publications

References 36 publications

Synaptic organization of the interstitial subdivision of the nucleus tractus solitarii and of its laryngeal afferents in the rat

Synaptic organization of the interstitial subdivision of the nucleus tractus solitarii and of its laryngeal afferents in the rat

Organization of synaptic transmission in the mammalian solitary complex, studied in vitro.

Visceral Afferents Directly Activate Catecholamine Neurons in the Solitary Tract Nucleus

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