RESUMEN
STUDY DESIGN: This study is to investigate the changes of vasomotion of intraradicular microvessels in vivo. OBJECTIVE: We have observed microvascular corrosion casts of the lumbar nerve root by scanning electron microscopy and used an immunohistochemical technique to investigate the presence and distribution of autonomic and sensory nerve in blood vessels of the nerve root. SUMMARY OF BACKGROUND DATA: It is generally considered that the genesis of radiculopathy associated with the degenerative conditions of the spine may result from both mechanical compression and circulatory disturbance. However, the neurogenic control of intraradicular blood flow has received little attention in the past. METHODS: For three-dimensional observation of intraradicular vessels, we used scanning electron microscopic examination of microvascular corrosion casts in ten Wister rats. To investigate the mechanism of vasomotion of the nerve root, we used immunohistochemical methods. The sections were incubated overnight with antisera to tyrosine hydroxylase, choline acetyl transferase, substance P, calcitonin-gene-related peptide, vasoactive intestinal peptide, somatostatin, neuropeptide Y, leucine-enkephalin, cholecystokinin octapeptide, brain-nitric oxide synthase, and endothelium-nitric oxide synthase. Abidin-biotin complex method was used as the immunohistochemical procedure and the sections were observed under the light microscope. RESULTS: The general view of whole vascular casts of the lumbar spinal cord and nerve roots showed a high density of vessels. Bifurcation or anastomoses of capillaries approximately took place at right angles in a T-shaped pattern and capillaries showed a lot of ring-like compressions. This ring-like compression on the cast may represent a vascular sphincter in the microvessels. This study also reveals the existence of perivascular adrenergic, cholinergic, peptidergic, and nitroxydergic innervation with a possible role in neurogenic regulation of nerve root circulation. CONCLUSION: Perivascular nerve plexuses around intraradicular microvessels suggest that the autonomic nerves play an important role in intraradicular circulation.
Asunto(s)
Vías Autónomas/ultraestructura , Vasos Sanguíneos/inervación , Vasos Sanguíneos/ultraestructura , Microcirculación/fisiología , Raíces Nerviosas Espinales/irrigación sanguínea , Sistema Vasomotor/ultraestructura , Animales , Vías Autónomas/metabolismo , Vasos Sanguíneos/metabolismo , Capilares/fisiología , Capilares/ultraestructura , Molde por Corrosión/métodos , Inmunohistoquímica , Masculino , Microscopía Electrónica de Rastreo , Músculo Liso Vascular/inervación , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/ultraestructura , Neuropéptidos/metabolismo , Neurotransmisores/metabolismo , Óxido Nítrico/metabolismo , Radiculopatía/metabolismo , Radiculopatía/fisiopatología , Ratas , Ratas Wistar , Flujo Sanguíneo Regional/fisiología , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/ultraestructura , Raíces Nerviosas Espinales/fisiología , Vasoconstricción/fisiología , Sistema Vasomotor/metabolismoAsunto(s)
Arterias/fisiología , Comunicación Celular/fisiología , Endotelio Vascular/metabolismo , Músculo Liso Vascular/metabolismo , Sistema Vasomotor/fisiología , Animales , Arterias/citología , Arterias/ultraestructura , Factores Biológicos/fisiología , Señalización del Calcio , Corteza Cerebral/irrigación sanguínea , Corteza Cerebral/ultraestructura , Conexinas/metabolismo , Conexinas/ultraestructura , Endotelio Vascular/citología , Endotelio Vascular/ultraestructura , Inhibidores Enzimáticos/farmacología , Uniones Comunicantes/ultraestructura , Masculino , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Modelos Cardiovasculares , Músculo Liso Vascular/citología , Músculo Liso Vascular/ultraestructura , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Ratas , Ratas Wistar , Sistema Vasomotor/ultraestructura , Proteína alfa-5 de Unión Comunicante , Proteína alfa-4 de Unión ComunicanteRESUMEN
Control of cerebral vasculature differs from that of systemic vessels outside the blood-brain barrier. The hypothesis that the endothelium modulates vasomotion via direct myoendothelial coupling was investigated in a small vessel of the cerebral circulation. In the primary branch of the rat basilar artery, membrane potential, diameter, and calcium dynamics associated with vasomotion were examined using selective inhibitors of endothelial function in intact and endothelium-denuded arteries. Vessel anatomy, protein, and mRNA expression were studied using conventional electron microscopy high-resolution ultrastructural and confocal immunohistochemistry and quantitative PCR. Membrane potential oscillations were present in both endothelial cells and smooth muscle cells (SMCs), and these preceded rhythmical contractions during which adjacent SMC intracellular calcium concentration ([Ca(2+)](i)) waves were synchronized. Endothelium removal abolished vasomotion and desynchronized adjacent smooth muscle cell [Ca(2+)](i) waves. N(G)-nitro-l-arginine methyl ester (10 microM) did not mimic this effect, and dibutyryl cGMP (300 muM) failed to resynchronize [Ca(2+)](i) waves in endothelium-denuded arteries. Combined charybdotoxin and apamin abolished vasomotion and depolarized and constricted vessels, even in absence of endothelium. Separately, (37,43)Gap27 and (40)Gap27 abolished vasomotion. Extensive myoendothelial gap junctions (3 per endothelial cell) composed of connexins 37 and 40 connected the endothelial cell and SMC layers. Synchronized vasomotion in rat basilar artery is endothelium dependent, with [Ca(2+)](i) waves generated within SMCs being coordinated by electrical coupling via myoendothelial gap junctions.
Asunto(s)
Corteza Cerebral/irrigación sanguínea , Conexinas/metabolismo , Endotelio Vascular/metabolismo , Uniones Comunicantes/metabolismo , Músculo Liso Vascular/metabolismo , Sistema Vasomotor/fisiología , Animales , Calcio/metabolismo , Comunicación Celular/fisiología , Corteza Cerebral/ultraestructura , Electrofisiología , Endotelio Vascular/ultraestructura , Uniones Comunicantes/ultraestructura , Inmunohistoquímica , Masculino , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Microscopía Confocal , Músculo Liso Vascular/ultraestructura , Bloqueadores de los Canales de Potasio/farmacología , Canales de Potasio/metabolismo , Ratas , Ratas Wistar , Sistema Vasomotor/ultraestructura , Proteína alfa-5 de Unión Comunicante , Proteína alfa-4 de Unión ComunicanteRESUMEN
Immunohistochemical methods for S-100 protein and neurone-specific enolase showed two types of nerve endings around the pulp microvasculature: the free endings, which comprise the major neural component and are distributed in all types of microvessel such as arterioles, venules and capillaries; and the varicose endings. The varicose ending was a less frequent, minor component observed only in the arterioles. Both immunohistochemical and ultrastructural observations confirmed that the varicose endings were the terminal axons of efferent vasomotor nerves. Further extensive ultrastructural examinations on the vasomotor nerves added the following new findings to our previous reports. Vasomotor nerves sometimes ramified into more than two terminal axons around arterioles, and most of these ramified axons ended in the adventitia-media junction of the arteriolar wall; however, nerve endings occasionally penetrated into the media. These findings suggest an intimate structural association between vasomotor nerves and arterioles in regulating the arteriolar microcirculation in human dental pulp by stimulating smooth-muscle cells not only of the outermost but also of the inner layers. Furthermore, the deep penetration of terminal axons into the arteriolar wall seems to provide effective regulation of pulpal blood flow under physiological and pathological conditions.
Asunto(s)
Pulpa Dental/irrigación sanguínea , Pulpa Dental/inervación , Sistema Vasomotor/ultraestructura , Adulto , Arteriolas/inervación , Arteriolas/ultraestructura , Axones/ultraestructura , Capilares/ultraestructura , Humanos , Técnicas para Inmunoenzimas , Microcirculación/ultraestructura , Microscopía Electrónica , Músculo Liso Vascular/inervación , Terminaciones Nerviosas/ultraestructura , Vesículas Sinápticas/ultraestructura , Vénulas/inervación , Vénulas/ultraestructuraRESUMEN
Vasomotor nerves in human dental pulp were more closely related to arterioles than to venules. Most were composed of unmyelinated fibres, which were mainly adrenergic. They appeared close to arterioles that were surrounded by a few layers of contractile smooth-muscle cells. The smaller arterioles with a diameter of 10-15 microns received a more intimate innervation by vasomotor nerves than did the larger. These vessels occasionally showed much narrower neuromuscular junctions than previously reported. Most of these nerve fibres were identified as adrenergic by the presence of chromaffin-positive synaptic vesicles detected by ultrastructural enzyme histochemistry. Their function appeared to be to regulate the blood flow and/or the blood pressure by stimulating smooth-muscle cells, resulting in contraction and a change in the calibre of the vessels. Capillaries and venules, which have a higher permeability, received weaker innervation by the vasomotor nerves than did arterioles. The intimate relation between vasomotor nerves and arterioles is related to the function of dental pulp in normal and pathological conditions.
Asunto(s)
Pulpa Dental/irrigación sanguínea , Pulpa Dental/inervación , Unión Neuromuscular/ultraestructura , Sistema Vasomotor/ultraestructura , Fibras Adrenérgicas/ultraestructura , Adulto , Arteriolas/inervación , Axones/ultraestructura , Membrana Basal/ultraestructura , Capilares/inervación , Fibras Colinérgicas/ultraestructura , Endotelio Vascular/citología , Endotelio Vascular/inervación , Humanos , Microcirculación , Microscopía Electrónica , Persona de Mediana Edad , Músculo Liso Vascular/citología , Músculo Liso Vascular/inervación , Terminaciones Nerviosas/ultraestructura , Fibras Nerviosas Mielínicas/ultraestructura , Células de Schwann/ultraestructura , Vesículas Sinápticas/ultraestructura , Vénulas/inervaciónRESUMEN
In the first stage of this study, peri- or intravascular unmyelinated nerve axon which was clearly different from that of the optic nerve was confirmed in the rabbit retina transmission electron microscopically. In the second stage, the correlation of these unmyelinated nerves and autonomic nerve was studied in rabbits and monkeys. For the purpose, wheat germ agglutinin horseradish peroxidase (WGA-HRP) was injected into the superior cervical ganglion. Electron microscopic observation of the retina 48 hrs after the injection of WGA-HRP showed deposit of its reaction product in the axon of the unmyelinated nerve located around the vascular wall and in the adventitia and smooth muscle cell in both rabbits and monkeys. This result clearly reveals the existence of an autonomic vasomotor in the retinal vessels at least in rabbits and monkeys.
Asunto(s)
Retina/ultraestructura , Sistema Vasomotor/ultraestructura , Animales , Macaca , Microscopía Electrónica , Conejos , Vasos Retinianos/ultraestructuraAsunto(s)
Vasos Sanguíneos/inervación , Sistema Vasomotor/crecimiento & desarrollo , Animales , Arterias/inervación , Axones/ultraestructura , Masculino , Músculo Liso Vascular/ultraestructura , Neurotransmisores/análisis , Ratas , Células de Schwann/ultraestructura , Cola (estructura animal)/irrigación sanguínea , Sistema Vasomotor/ultraestructuraRESUMEN
Vasomotor function in ear vessels of rabbits was tested in animals with experimental autonomic neuropathy (EAUN), experimental allergic neuritis (EAN), and controls. Reflex vasodilatation was impaired in animals with EAUN but not in EAN or control rabbits. Ultrastructural examination of paravertebral sympathetic chain, perivascular nerves, and perivascular tissue showed similar changes in all animals differing in degree only. Occasional lymphocytes were seen in paravertebral chains of controls but large numbers of lymphocytes and macrophages occurred in EAUN and EAN. No active destruction of myelinated or unmyelinated fibers could be seen. Perivascular nerves showed similar cellular infiltrates and basophils were found in perivascular spaces of ear vessels which were most abundant in animals with EAUN. Fibre-size spectra analysis of unmyelinated fibres in the paravertebral sympathetic chain showed a shift to the left suggesting regeneration of unmyelinated axons in both EAN and EAUN. No specific immunofluorescence against neuronal components could be demonstrated in sensitized animals. It is concluded that the functional disturbance of reflex vasomotion in EAUN is not accompanied by specific ultrastructural lesions nor could neuronal components be immunologically implicated in the disorder. Regeneration of unmyelinated axons and recovery of function after some weeks together with abundance of basophils in perivascular tissue of sensitized animals, suggests that a localized inflammation may have occurred, the basophils interfacing between foreign antigens, the serum cascade systems, and other inflammatory cells. The usefulness of EAUN as a model for acute pandysautonomia in man remains to be determined.
Asunto(s)
Enfermedades Autoinmunes/patología , Reflejo Anormal/patología , Sistema Nervioso Simpático/ultraestructura , Sistema Vasomotor , Animales , Enfermedades del Sistema Nervioso Autónomo/patología , Oído Externo/irrigación sanguínea , Humanos , Microscopía Electrónica , Neuritis/patología , Conejos , Sistema Vasomotor/fisiopatología , Sistema Vasomotor/ultraestructuraAsunto(s)
Cuerpo Carotídeo/ultraestructura , Animales , Cuerpo Carotídeo/irrigación sanguínea , Cuerpo Carotídeo/citología , Cuerpo Carotídeo/embriología , Células Quimiorreceptoras/ultraestructura , Gránulos Citoplasmáticos/ultraestructura , Vías Eferentes , Ganglios/ultraestructura , Uniones Intercelulares/ultraestructura , Terminaciones Nerviosas/ultraestructura , Inhibición Neural , Sistema Nervioso Parasimpático/citología , Sistema Nervioso Simpático/citología , Sinapsis/ultraestructura , Sistema Vasomotor/ultraestructuraRESUMEN
The autonomic innervation of the conus papillaris has been observed by electron microscopy in Lacerta viridis, muralis, Anguis fragilis and Zonosaurus ornatus. Bundles of nerve fibres accompanying blood vessels penetrate the conus at the level of the intraocular portion of the optic nerve. Within the conus proper, different aspects are described: bundles of fibres from which some axons can be separated, aggregates of axons with varicosities enclosed within the cytoplasm of pigmented cells, isolated preterminal axons or varicose terminals encircled by pigment cell cytoplasm or cytoplasmic processes, and naked terminals. The observed innervation is to be related to blood vessel vasomotor activity or to pigment cell motility. This problem remains unsolved.
Asunto(s)
Lagartos/anatomía & histología , Vasos Retinianos/inervación , Sistema Vasomotor/ultraestructura , Animales , Fibras Nerviosas/ultraestructura , Nervio Óptico/ultraestructura , Vasos Retinianos/ultraestructura , Vesículas Sinápticas/ultraestructuraRESUMEN
Ultrastructure of varicous dilatation of the axons composing small neuronal fasciculi in the sympathetic plexus of the rabbit coronary artery has been studied. According to the data of three dimensional reconstruction, space structure of three neuronal fasciculi has been restorted. Axons of every fasciculus form varicous dilatation at the same area along their course. A lemmocytic process, accompanying the axon as a thin cylinder at the intervaricous part flattens, in the area of varicous dilatations. and embraces all the axons, thus forming a peculiar functional unit of the neuronal fasciculus. From the data obtained and those of literature, it is possible to suggest that not only single axons situating in the nearest approximation to smooth muscle cells, but also single neuronal fasciculi having in their composition axons with varicous dilatation might effectively influence the smooth musculature of the vascular wall.
Asunto(s)
Vasos Coronarios/inervación , Sistema Vasomotor/ultraestructura , Animales , Axones/ultraestructura , ConejosRESUMEN
The fine structure of nerve plexus in the rabbit abdominal aorta, ear and coronary arteries has been studied. Four types of the nerve fibre organization corresponding to different levels of sectioning their preterminal and terminal zones have been determined. Axons form large bundles which lose Schwann sheathes and divide into smaller and even single axons as they approach the distal end. Single axons make up contacts with effector cells without forming special synaptic structures. The smalles distance found between axon membranes and smooth muscle cells is 20 nm and 50 nm for the ear and coronary arteries, respectively. In the abdominal aorta, axons lie at a distance of several microns from the muscle sheath. Such arrangement supports the hypothesis of a "distant" nervous influence on the smooth muscle and indicates that the space of nervous influence comprises the tissue surrounding the blood vessel
Asunto(s)
Arterias/inervación , Nervios Periféricos/ultraestructura , Animales , Aorta Abdominal/inervación , Vasos Coronarios/inervación , Oído/irrigación sanguínea , Microscopía Electrónica , Músculo Liso/inervación , Conejos , Sistema Vasomotor/ultraestructuraRESUMEN
The anatomy of the autonomic sympathetic vasomotor nerve supply of bone was studied in rabbits by methods of histochemistry, and fluorescent and electron microscopy. Our observations show that the intraosseous vessels are richly supplied by adrenergic nerves. The large primary nerves are located on or about the surface of the vessel; the medium sized secondary nerves spiral around the long axis of vessels lying more deeply in the tunica adventitia; and the fine tertiary nerves form a rich plexus at the outer area of the tunica media. The tertiary nerves have various structures which probably contain neurotransmitter substance--that is, noradrenaline--and function as neuro-vasomuscular synapses. The sympathetic nerve supply of bone originates from the appropriate ganglion, and in the case of the tibial diaphysis it descends through the sciatic nerve and thereafter mainly through the medial popliteal nerve and enters the bone alongside the nutrient artery.