Ultrastructural studies on catecholaminergic terminals and GABAergic neurons in nucleus tractus solitarius of the rat medulla oblongata

1984 ◽  
Vol 302 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Bang H. Hwang ◽  
Jang-Yen Wu
Keyword(s):  
Medulla Oblongata ◽  
Nucleus Tractus Solitarius ◽  
Gabaergic Neurons ◽  
Ultrastructural Studies

Inhibitory Vasomotor Neurons in the Caudal Ventrolateral Medulla Oblongata

Physiology ◽  
1991 ◽  
Vol 6 (3) ◽  
pp. 139-141 ◽  
Author(s):  
WW Blessing
Keyword(s):  
Medulla Oblongata ◽  
Gabaergic Neurons ◽  
Ventrolateral Medulla ◽  
Vasomotor Tone ◽  
Caudal Ventrolateral Medulla ◽  
Premotor Neurons ◽  
Sympathetic Vasomotor Tone

Tonically active, probably GABAergic, neurons in the caudal ventrolateral medulla oblongata decrease sympathetic vasomotor tone by directly inhibiting sympathoexcitatory premotor neurons in the rostral medulla. These caudal inhibitory vasomotor neurons may constitute the inhibitory link in the central baroreceptor-vasomotor pathway.

Quantitative and immunohistochemical analysis of neuronal types in the mouse caudal nucleus tractus solitarius: Focus on GABAergic neurons

2008 ◽  
Vol 35 (3) ◽  
pp. 275-284 ◽  
Author(s):  
Tomoaki Okada ◽  
Yasura Tashiro ◽  
Fusao Kato ◽  
Yuchio Yanagawa ◽  
Kunihiko Obata ◽  
...  
Keyword(s):  
Nucleus Tractus Solitarius ◽  
Immunohistochemical Analysis ◽  
Gabaergic Neurons ◽  
Neuronal Types

Substance P in the ventrolateral medulla oblongata regulates ventilatory responses

1990 ◽  
Vol 68 (6) ◽  
pp. 2631-2639 ◽  
Author(s):  
Z. Chen ◽  
J. Hedner ◽  
T. Hedner
Keyword(s):  
Substance P ◽  
Medulla Oblongata ◽  
Nucleus Tractus Solitarius ◽  
Minute Ventilation ◽  
Ventrolateral Medulla ◽  
Cervical Cord ◽  
Co2 Response ◽  
Caudal Region ◽  
Ventilatory Responses ◽  
Cervical Segment

Local injection of substance P (SP) into the ventral portion of the nucleus gigantocellularis, nucleus reticularis lateralis, and nucleus retrofacialis of the ventrolateral medulla oblongata (VLM) or direct application on the ventral surface of the medulla oblongata caused marked stimulation of tidal volume (VT) and/or minute ventilation (VE). The ventilatory response to hypoxia was significantly blunted after SP in the VLM but not in the dorsal medulla oblongata (DM) (nucleus tractus solitarius). The SP antagonist [D-Pro2,D-Trp7,9]SP almost completely inhibited this response when applied locally to a wide area of the superficial layer of the VLM but not of the DM. Unilateral or bilateral application of 0.3-1.5 nmol of the SP antagonist in the VLM (corpus trapezoideum and the caudal region extending from the rootlets of the nucleus hypoglossus to the first cervical segment) markedly attenuated the response to a 5% CO2 inhalation. The inhibition of the CO2 response was seen after [D-Pro2,D-Trp7,9]SP in the rostral areas of the medulla oblongata corresponding to the corpus trapezoideum and the caudal region extending from the rootlets of the nucleus hypoglossus to the first cervical segment of the cervical cord. Electric somatosensory-induced ventilatory stimulation could be depressed by approximately 70% by [D-Pro2,D-Trp7,9]SP locally applied on the surface of the VLM. We conclude that SP is involved in the hypoxic, hypercapnic, and somatosensory ventilatory responses in the rat. However, these respiratory reflexes are mediated via different neuronal pools in the medulla oblongata, mainly the VLM.

Local effects of substance P on respiratory regulation in the rat medulla oblongata

1990 ◽  
Vol 68 (2) ◽  
pp. 693-699 ◽  
Author(s):  
Z. B. Chen ◽  
J. Hedner ◽  
T. Hedner
Keyword(s):  
Substance P ◽  
Medulla Oblongata ◽  
Nucleus Tractus Solitarius ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Ventrolateral Medulla ◽  
Response Patterns ◽  
Respiratory Response ◽  
Inspiratory Time ◽  
Ventral Medullary Surface

The effect of substance P (SP) and the SP antagonist [D-Pro2,D-Trp7,9]-SP on basal ventilation was investigated in halothane-anesthetized rats. Microinjections of SP (0.4-1.5 nmol) into the ventrolateral medulla oblongata (VLM), (nuclei gigantocellularis, facialis, ambiguus, and reticularis lateralis) or into the dorsomedial medulla oblongata (DM, nucleus tractus solitarius) and its ventral surroundings dose dependently increased tidal volume (VT) and/or minute ventilation. In sensitive areas, the ventilatory stimulation was initiated within minutes, peaked around 8-10 min, and slowly returned to normal over 30-45 min after the injection. In the VLM sites, the increase in VT was generally accompanied by a decrease in respiratory frequency (f), whereas in the DM, f increased in parallel with VT. Furthermore, within the VLM, the respiratory response patterns differed with the definite location of the SP injection. A shortening of inspiratory time was observed in the ventromedial part, the ventrolateral portion of the nucleus paragigantocellularis and ventral to the nucleus facialis. In contrast, a lengthening of expiratory time was seen when SP was injected or applied more laterally along the ventral portion of nucleus facialis and near or directly on the ventral medullary surface. Application of [D-Pro2, D-Trp7,9]SP before or after SP completely antagonized the excitatory effects of SP on ventilation. The SP antagonist administered into the VLM decreased the ventilatory response to hypoxic breathing but caused no change during hyperoxic conditions.

scholarly journals Somatostatin-immunoreactive nerve cell bodies and fibers in the medulla oblongata et spinalis.

1979 ◽  
Vol 27 (10) ◽  
pp. 1391-1393 ◽  
Author(s):  
W G Forssmann ◽  
C Burnweit ◽  
T Shehab ◽  
J Triepel
Keyword(s):  
Medulla Oblongata ◽  
Nucleus Tractus Solitarius ◽  
Nerve Fibers ◽  
Dense Networks ◽  
Nucleus Reticularis ◽  
Raphe Magnus ◽  
Upper Cervical ◽  
Lower Lumbar ◽  
Nucleus Vestibularis ◽  
Nucleus Cuneatus

Complete serial sectioning of the medulla oblongata in monkey, cat, guinea pig, and japanese dancing mouse and incubation for somatostatin-immunoreaction was carried out. Numerous regions of the medulla oblongata such as the nucleus reticularis gigantocellularis, nucleus cuneatus et gracillis, nucleus raphe magnus, nucleus tractus solitarius, nucleus vestibularis, and parts of the oliva contain dense networks of somatostatin-immunoreactive nerve fibers. Cell bodies were seen in the nucleus reticularis medullae oblongatae. In the spinal cord the sections from each segment were analyzed, showing the highest concentrations of somatostatinergic fibers in the substantia gelantinosa of the columna dorsalis. Cell bodies were seen in the zona intermedia centralis, especially in the upper cervical segments. Many positive fibers were also seen in the entire zona intermedia and the columna ventralis. Especially prominent was the immunoreactivity in the zona intermediolateralis of the thoracic segments and the columna ventralis of the lower lumbar and sacral segments.

scholarly journals In Vitro Research of the Alteration of Neurons in Vagal Core in Medulla Oblongata at Asphyxic Deaths

2010 ◽  
Vol 10 (3) ◽  
pp. 251-259
Author(s):  
Naim Haliti ◽  
Hilmi Islami ◽  
Nevzat Elezi ◽  
Ragip Shabani ◽  
Bedri Abdullahu ◽  
...  
Keyword(s):  
Vagus Nerve ◽  
Medulla Oblongata ◽  
Nucleus Tractus Solitarius ◽  
Morphological Changes ◽  
Testing System ◽  
Autopsy Material ◽  
Universal Testing ◽  
Cytoplasmic Vacuolization ◽  
Death Cases

The aim of this study was to research the morphological changes of neurons in the vagus nerve nuclei in medulla oblongata in asphyxia related death cases. Morphological changes that were investigated were mainly in the dorsal motor respiratory center (DMRC), nucleus tractus solitarius (nTS) and nucleus ambigus (nA) in the medulla oblongata. In our research, the autopsy material from asphyxia related death cases was used from various etiologies: monoxide carbon (CO), liquid drowning, strangulation, electricity, clinical-pathological death, firing weapon, explosive weapon, sharp and blunt objects and death cases due to accident. The material selected for research was taken from medulla oblongata and lungs from all lobes. The material from the medulla oblongata and lungs was fixed in a 10% solution of buffered formalin. Special histochemical methods for central nervous system (CNS) were employed like: Cresyl echt violet, toluidin blue, Sevier-Munger modification and Grimelius. For stereometrical analysis of the quantitative density of the neurons the universal testing system Weibel M42 was used. The acquired results show that in sudden asphyxia related death cases, there are alterations in the nuclei of vagal nerve in form of: central chromatolysis, axonal retraction, axonal fragmentation, intranuclear vacuolization, cytoplasmic vacuolization, edema, condensation and dispersion of substance of Nissl, proliferation of oligodendrocytes, astrocytes and microglia. The altered population of vagus nerve neurons does not show an important statistica! significarne compared to the overall quantity of the neurons in the nuclei of the vagus nerve (p<0,05).

scholarly journals Glutamatergic inputs to the CVLM independent of the NTS promote tonic inhibition of sympathetic vasomotor tone in rats

2008 ◽  
Vol 295 (4) ◽  
pp. H1772-H1779 ◽  
Author(s):  
Daniel A. Mandel ◽  
Ann M. Schreihofer
Keyword(s):  
Sympathetic Nerve Activity ◽  
Nucleus Tractus Solitarius ◽  
Excitatory Input ◽  
Gabaergic Neurons ◽  
Tonic Inhibition ◽  
Ventrolateral Medulla ◽  
Respiratory Drive ◽  
Vasomotor Tone ◽  
Nerve Activity ◽  
Sympathetic Vasomotor Tone

GABAergic neurons in the caudal ventrolateral medulla (CVLM) are driven by baroreceptor inputs relayed via the nucleus tractus solitarius (NTS), and they inhibit neurons in rostral ventrolateral medulla to reduce sympathetic nerve activity (SNA) and arterial pressure (AP). After arterial baroreceptor denervation or lesions of the NTS, inhibition of the CVLM continues to increase AP, suggesting additional inputs also tonically activate the CVLM. This study examined whether the NTS contributes to baroreceptor-independent drive to the CVLM and whether glutamate promotes baroreceptor- and NTS-independent activation of the CVLM to tonically reduce SNA. In addition, we evaluated whether altering central respiratory drive, a baroreceptor-independent regulator of CVLM neurons, influences glutamatergic inputs to the CVLM. Splanchnic SNA and AP were measured in chloralose-anesthetized, ventilated, paralyzed rats. The infusion of nitroprusside decreased AP below threshold for baroreceptor afferent firing (<50 mmHg) and increased SNA to 209 ± 22% ( P < 0.05), but the subsequent inhibition of the NTS by microinjection of the GABAA agonist muscimol did not further increase SNA. In contrast, after inhibition of the NTS, blockade of glutamatergic inputs to CVLM by microinjection of kynurenate increased SNA (274 ± 54%; P < 0.05; n = 7). In vagotomized rats with baroreceptors unloaded, inhibition of glutamatergic inputs to CVLM evoked a larger rise in SNA when central respiratory drive was increased (219 ± 16% vs. 271 ± 17%; n = 5; P < 0.05). These data suggest that baroreceptor inputs provide the major drive for the NTS-mediated excitation of the CVLM. Furthermore, glutamate tonically activates the CVLM to reduce SNA independent of the NTS, and this excitatory input appears to be affected by the strength of central respiratory drive.

Microvascular specializations promoting rapid interstitial solute dispersion in nucleus tractus solitarius

1990 ◽  
Vol 259 (6) ◽  
pp. R1131-R1138 ◽  
Author(s):  
P. M. Gross ◽  
K. M. Wall ◽  
J. J. Pang ◽  
S. W. Shaver ◽  
D. S. Wainman
Keyword(s):  
Medulla Oblongata ◽  
Nucleus Tractus Solitarius ◽  
Area Postrema ◽  
Morphological Evidence ◽  
Perivascular Spaces ◽  
Autonomic Functions ◽  
Luminal Diameter ◽  
Small Vessels ◽  
Brain Barrier Permeability ◽  
The Rich

Nucleus tractus solitarius (NTS), an aggregate of several individual nuclear groups in the dorsal medulla oblongata, is involved in virtually all autonomic functions as the first synaptic site in the brain for many peripheral viscerosomatic inputs. We found morphological evidence that dorsocaudal subregions of rat NTS (approximately 800 microns caudal from obex) had fenestrated capillaries and enlarged Virchow-Robin (perivascular) spaces that were similar to those in area postrema but unlike capillaries elsewhere in the medulla oblongata. Complexes of microvessels, consisting of up to 10 small vessels with smooth muscle layers (luminal diameters of 10-45 microns) and several capillaries (average luminal diameter of 4.5 microns), were located in the dorsal midline of NTS within large Virchow-Robin spaces measuring some 2,000 microns 2 in area. In physiological studies, we determined that most of NTS had a definable blood-brain barrier [permeability-surface area (PS) products for a neutral amino acid near 0], but medial and lateral aspects of the commissural subnucleus of NTS had PS products of 16-63 microliters.g-1.min-1 for alpha-[14C]aminoisobutyric acid 12 s after intravenous injection. Microvascular differentiations permitting such brisk tracer influx from blood resemble those of area postrema and appear to afford the rich neuropil of commissural NTS with a constant stream of blood-borne information for expediting its regulation of viscerosensory and autonomic functions.

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