Functional subdivisions of the nucleus tractus solitarii of the rat as determined by circulatory and respiratory responses to electrical stimulation of the nucleus

Onai, Takeshi; Saji, Makoto; Miura, Mitsuhiko

doi:10.1016/0165-1838(87)90022-1

Cited by 55 publications

(12 citation statements)

References 15 publications

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“…In addition, the distribution region of the TH-IR neurons projecting to the Ce is also that where vagal afferents terminate (Kalia and Sullivan, 1982;Onai et al, 1987). These data suggest that GABAergic axon terminals probably regulate visceral transmission from the NTS to the Ce.…”

Section: Light Microscopic Distributions Of Medullary Catecholaminergmentioning

confidence: 92%

Evidence of ?-aminobutyric acidergic control over the catecholaminergic projection from the medulla oblongata to the central nucleus of the amygdala

1997

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It is known that the nucleus of the solitary tract (NTS) and the ventrolateral medulla (VLM) project to the central nucleus of the amygdala (Ce), conveying visceral information. Conversely, the Ce sends projections to the NTS and the VLM. To understand better the role of catecholamine and gamma-aminobutyric acid (GABA) in these reciprocal connections, experiments were performed by combining lectin-conjugated horseradish peroxidase (WGA-HRP) anterograde and retrograde transport with preembedding immunocytochemistry to detect tyrosine hydroxylase (TH), and postembedding immunocytochemistry to detect GABA. The light microscopic study suggested that the majority of neurons in the NTS and the VLM projecting to the Ce were TH immunoreactive (TH-IR). Most of them were located at the level of the obex. Under the electron microscope, the GABAergic and non-GABAergic terminals were found to form synaptic contacts with the TH-(IR) or Ce-projecting or TH-IR/Ce-projecting double-labelled neurons of the NTS and VLM. The GABAergic terminals mostly formed symmetrical synaptic contacts with the postsynaptic structure in which perikarya (14-19%), dendrites (79-84%), and spines (2%) were observed. Approximately 94% of the axon terminals in the NTS and 90% of those in the VLM arising from the Ce were GABAergic and appeared not to form synaptic contacts with the TH-IR or Ce-projecting neurons in these regions. The present results demonstrated that the catecholaminergic neurons of the NTS and VLM projecting to the Ce receive an extensive GABAergic innervation and that the amygdala projection to the medulla is mostly GABAergic.

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Section: Light Microscopic Distributions Of Medullary Catecholaminergmentioning

confidence: 92%

Evidence of ?-aminobutyric acidergic control over the catecholaminergic projection from the medulla oblongata to the central nucleus of the amygdala

1997

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“…Action potentials of SPNs were recorded extracellularly through one barrel containing 4 M NaCl (2 MIQ) of either a five-or seven-barrel glass micropipette assembly as previously described (Lewis & Coote, 1990 Having located such a suitable site, the effect of NTS stimulation on SPN firing frequency was determined using single-pulse stimulation (0-1 ms, 1 Hz, 10-100 V, < 100 1uA; Lewis & Coote, 1993b). Stimulation in adjacent regions of the NTS, sometimes < 0 5 mm away (Onai, Saji & Miura, 1987) evoked vasopressor responses which were not investigated further. Single identified SPNs were located as previously described (Gilbey et al 1982;Lewis & Coote, 1990) 80-90 min-'; tidal volume 1P8 ml) so as to produce an alkalosis (arterial Pco2, 33 + 5 mmHg; Po2 > 100 mmHg; arterial blood sample measured once during each experiment using a Stat Profile 3 analyser (Nova, MA, USA)).…”

Section: Methods Animals and Surgerymentioning

confidence: 99%

Chemical mediators of spinal inhibition of rat sympathetic neurones on stimulation in the nucleus tractus solitarii.

Lewis

Coote

1995

The Journal of Physiology

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1. This study was undertaken to gain more direct evidence of the pathways and neurochemical mediators of a spinally mediated baroreceptor inhibition of sympathetic preganglionic neurones (SPNs). 2. For this purpose, single-pulse electrical stimulation within identified vasodepressor regions of the nucleus tractus solitarii (NTS) was used together with extracellular recordings of single antidromically identified SPNs in the T2 segment of the spinal cord of anaesthetized rats. 3. The actions of agonists and antagonists of inhibitory amino acids on the NTS-induced inhibitions were determined, when they were iontophoretically applied in the vicinity of SPNs via a multibarrel micropipette assembly. 4. Extracellular recordings were made from sixty-nine SPNs. In forty-four SPNs, NTS stimulation elicited a period of inhibition of activity in both spontaneous and 'D,L-homocysteic acid-driven' SPNs with a latency to onset of 60 + 6 ms and a magnitude of 80 + 3%. 5. In six out of eight neurones, the NTS-induced inhibition was reduced by 74 + 16% during the application of the glycine antagonist strychnine (0-10 nA, 5-10 min) with doses that selectively blocked the inhibitory effect of iontophoretically applied glycine. 6. In nine out of nine neurones, the NTS-induced inhibition was reduced by 38 + 6 % during the application of the GABAA antagonist bicuculline (5-15 nA, 4-14 min) with doses that selectively blocked the inhibitory effect of iontophoretically applied GABA. 7. In two SPNs, the actions of strychnine and bicuculline were shown to be additive in blocking the NTS inhibition. 8. The selective GABAB antagonists,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and CGP 55845A

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“…The role of the intermediate, interstitial, ventrolateral, and commissural subnuclei of the solitary tract (the dorsal respiratory group) in respiratory control includes the relaying of visceral sensory information such as chemoreception and pulmonary stretch to the ventral respiratory group. Furthermore, stimulation of the caudal commissural or intermediate nucleus of the solitary tract in the rat with excitatory amino acids (Bonham and McCrimmon, 1990) or electrical current (Onai et al, 1987) causes hypopnea. However, a parabrachial input to the nucleus of the solitary tract might participate in apneustic responses by disturbing the feedback signals from lung inflation, thus diminishing exhalation time and advancing the timing of the next breath.…”

Section: Respiratory Responses To Pb Microstimulationmentioning

confidence: 99%

Topographic organization of respiratory responses to glutamate microstimulation of the parabrachial nucleus in the rat

1994

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The parabrachial complex, also known as the pneumotaxic center or pontine respiratory group, has long been recognized as an important participant in respiratory control. One line of evidence supporting this idea is the demonstration of changes in breathing pattern following injection of neuroactive substances into or near the parabrachial complex. However, it is not yet known exactly which cell groups and projections mediate those responses. In order to address this issue, we explored the topographic organization of respiratory responses to chemical stimulation of the parabrachial complex of the rat and examined the descending projections of the most sensitive sites. Injection of glutamate (5–100 pmol) at specific sites in or near the parabrachial nucleus produced three distinct site-specific response patterns. First, hyperpnea followed glutamate injection into far rostral and midcaudal areas of the Kolliker-Fuse nucleus and most of the lateral parabrachial nucleus, including the external lateral, central lateral, dorsal lateral, and superior lateral subnuclei. Threshold hyperpneic effects were manifested as single, deepened breaths of premature onset. Suprathreshold doses of glutamate at these locations produced tachypnea. Neurons in these sites projected to the ventral respiratory group in the ventrolateral medulla. Second, the most intense inspiratory facilitatory responses were seen at mid to rostral levels of the Kolliker-Fuse nucleus, near the ventrolateral tip of the superior cerebellar peduncle. Even at threshold doses of glutamate, exhalation was incomplete, resulting in a breathing pattern that resembled apneusis (an inspiratory cramp). This site contained an especially dense cluster of neurons that projected either to the ventrolateral medulla or to the dorsal respiratory group in the nucleus of the solitary tract, but not to both areas. The third type of response, decreases in respiratory rate, occurred following glutamate injection at the most lateral and ventral boundaries of the Kolliker- Fuse nucleus. The most sensitive apneic sites were not found in the parabrachial nucleus but along the dorsal and medial edge of the principal sensory trigeminal nucleus and extending ventrally between the sensory and motor trigeminal nuclei. Scattered neurons in these sites were retrogradely labeled from the ventral but not the dorsal respiratory group. These results indicate that there are anatomically and functionally distinct cell populations in and near the parabrachial complex that, when chemically stimulated, can produce specific and sometimes opposing effects on respiration. The predominant effect of lateral parabrachial stimulation is respiratory facilitation, while inhibitory effects are elicited by trigeminal injections of glutamate.

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Functional subdivisions of the nucleus tractus solitarii of the rat as determined by circulatory and respiratory responses to electrical stimulation of the nucleus

Cited by 55 publications

References 15 publications

Evidence of ?-aminobutyric acidergic control over the catecholaminergic projection from the medulla oblongata to the central nucleus of the amygdala

Evidence of ?-aminobutyric acidergic control over the catecholaminergic projection from the medulla oblongata to the central nucleus of the amygdala

Chemical mediators of spinal inhibition of rat sympathetic neurones on stimulation in the nucleus tractus solitarii.

Topographic organization of respiratory responses to glutamate microstimulation of the parabrachial nucleus in the rat

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