Structure and homodynamia of the intersegmental connection TI-TII

The reason to consider the second thoracic cerebrospinal nerve (Th2) as one of the sources of the brachial plexus is the fact of the intersegmentary connection between Th1 and Th2 by means of a neural branch situating on the internal surface of the thorax near the vertebral column (the intrathoracic or paravertebral branch). However, not all cases of the intersegmentary connection Th1-Th2 should be regarded only as participation of Th2 in the formation of the brachial plexus, this is conditioned by certain peculiarities of its structure and by the character of interconnections with the I intercostal nerve. The macro-microscopic method demonstrates that the intersegmentary connection Th1-Th2 includes somatic and vegetative components, that to the same extent participate both in formation of the brachial plexus and in the I intercostal nerve. The intersegmentary connection Th1-Th2 is considered as a vegetative neural structure, containing somatic conductors and is considered as a homologue of superficial connective branches. It is the way, by which sympathetic fibers can reach the brachial plexus from the segment situating below, without passing through the superior thoracic nodes of the sympathetic trunk.     

Connections between neurons of sympathetic ganglia and the myenteric nerve plexus of the mammalian colon

By means of retrograde transport of the fluorescent marker primulin the initial part of the sympathetic innervation of the myenteric nervous plexus of the descending colon has been characterized in cats and guinea pigs. When primulin is injected into the myenteric nervous plexus, marked neurons are revealed in the caudal mesenteric ganglion, in the celiac plexus ganglia, in the sympathetic trunk ganglia. The marked nervous populations of the extramural sympathetic ganglia differ in their form, size, number of neurons and their distribution.     

Neural apparatus of the wall of the ductus deferens in the dog

While studying the innervation sources of the deferent duct in 10 dogs, 2-3 nerves have been revealed that take their origin at the pelvic neural plexus and approach the duct together with the blood vessels at the pelvic neural plexus and approach the duct together with the blood vessels at the place where it crosses the ureter ("the vascular-neural hilus"). In the experiment performed in 65 dogs the nature of these sources has been revealed. The motor innervation is presented by the nodes of the celiac plexus, of the lumbar and sacral parts of the sympathetic trunk, of the subceliac, gonadal and splanchic pelvic nerves, and the sensitive innervation is multisegmental and is performed by the intravertebral nodes L2-S3. Quantitative investigation of the degenerated neural fibers in the dog deferent duct wall demonstrates that the innervation sources mentioned above participate te a various degree along the course of the organ. In the "hilus" the nerves of the dog deferent duct are divided into the proximal nad distal groups. The proximal group runs towards the prostate and forms a plexus with large loops connected with the neural plexuses of the urinary bladder, the ureter and the prostate. It has small neural nodes. The distally directed nerves run, together with the blood vessels, in the deferent duct towards the epididymis. In the deferent duct wall, adventitila, muscular and mucous neural plexus are found, the cholinergic component prevailing the adrenergic one. The plexuses are somewhat better developed at the beginning of the deferent duct and they are especially pronounced in the ampule. The receptors of the organ's wall are simple, poorly branching.     

Effect of spinal cord compression on cyclic 3',5'-guanosine monophosphate in the white matter columns of rabbit

Changes in the level of cyclic 3',5'-guanosine monophosphate (cGMP) were studied one day after a surgically induced spinal cord constriction performed at the Th7 segment level in the dorsal, lateral and ventral white matter columns and in the non-compartmentalized white matter of Th5-Th6 segments, i.e., above the site of the spinal cord constriction and in Th8-Th9 segments, located below the spinal cord constriction. The midthoracic spinal cord constriction caused a significant decrease in the level of cGMP in the ventral column of Th5-Th6 segments and a significant increase in the lateral column of Th8-Th9 segments. The level of cGMP in the dorsal column, located either rostrally or caudally to the site of the spinal cord injury, remained unchanged. In addition, no significant changes in the level of cGMP were found in the non-compartmentalized white matter of Th5-Th6 and Th8-Th9 segments in response to constriction of the Th7 segment.     

Projection of the celiac plexus to the afferent centers demonstrated by the horseradish peroxidase retrograde transport method

Using the horseradish peroxidase (HP) retrograde method for ascertaining connections of the celiac plexus of the white rat with various afferent centers, HP-marked neurocytes have been revealed in caudal nodes of the vagus nerves and in spinal nodes at the Th4-L2 level. Negative results have been obtained at investigation of the cervical spinal nodes and intramural nodes in the cat ileocecal part. Similar data are obtained, when connections of the celiac plexus with the same area of the cat gut are investigated. Therefore, the problem on interrelations of the celiac plexus with the proper afferent centers of the diaphragmatic+ nerve and the second type cells of Dogel in the cat intramural ganglia is still disputable.     

The intratruncal structure of the connections between the sympathetic trunk and the human brachial plexus and their individual differences]

The intratrunkal structure of 219 superficial and profound connecting branches between the sympathetic trunk and humeral plexus was studied in 18 people. Staining after Weigert--Pal was used followed by calculation of the absolute number of myelinated fibres. Individual features were revealed both in the diameter and in the intratrunkal plexus structure of connections as well as in the amount of myelinated fibres in similar connecting branches in different people. Qualitative distinctions between superficial and profound connections were noted. Intratrunkal characteristics of the reflect the general form of the structure of the sympathetic trunk. They constantly contain myelinated fibres coming not only from the thoracic part of the spinal cord but also from its jugular part. Their pathway is the more complex and diversive the more distributed are ganglionic masses of the sympathetic trunk. It goes from segments C4--C5 in the scattered form of the sympathetic trunk structure and from segments C6--C7--C8 in the concentrated form.     

Extra-organic sources of innervation of the sigmoid]

By means of horseradish peroxidase administration into the wall of the sigmoid colon central part, localization, relative amount, body forms and size of the neurons, dealing with innervation of the given part of the colon have been determined. Labelled neurons are present in the colon wall, in ganglia of the caudal mesenteric artery nervous plexus, in the caudal and cranial mesenteric ganglia in the celiac plexus ganglia, in nodes and internodal branches of the lumbar part of the sympathetic trunk (the left one predominantly) and in the spinal ganglia from TXIII up to LVII. In the grey substance of the spinal cord labelled neurons are not revealed. The main part of the postganglionar sympathetic neurons, projecting their axons to the sigmoid colon, are situated in the caudal mesenteric ganglion. In the spinal ganglia the most part of the labelled neurons are to the left at the level of LII-LVI, to the right--at the level of LII-LV. The optimal time for revealing the greatest number of the labelled neurons are the 1st-3d days after administration of the enzyme. Capture of the lable takes place later in the neurons of those ganglia, which are situated more further from the place of peroxidase administration.     

Ultrastructure of celiac plexus nodes in the dog

A normal structure of the celiac plexus nodes has been studied in 12 mature dogs. As demonstrate the results of the investigation, gangliocytes of the celiac plexus are characterized with a well developed granular cytoplasmic reticulum and a large number of Golgi complexes. In perikaryon of the gangliocytes, an essential number of mitochondria, microtubules, free ribosomes and polysomes, lysosomes, multivesicular bodies, agranular and granular vesicles and neurofilaments are found. The gangliocyte has one nucleus which occupies about 1/3 of the whole area of the cell. The nucleus is rich in chromatin. The nucleolus makes about 1/5 of the whole area of the nucleus and is intensively rich in heterochromatin. In the celiac plexus nodes amyelinated neural fibers predominate. Dendrites in the gangliocytes differ from axons by a higher electron density of their matrix and contain the same organells that does the perikaryon of the gangliocyte. Rather complex glyoneuronal interrelations are observed in the canine celiac plexus nodes. Synapses are revealed in all ganglionar zones. The axodendritic synaptic contacts predominate over the axosomatic ones.     

Information of the structuro-functional characteristics of sympathetic afferents

Visceral nerves have a lot of sensitive conductors of double nature. One of them are presented by dendrites of pseudounipolar cells of cerebrospinal nodes, others - in the form of amyelinic (or, sometimes, fine myelinic) fibres - are axons of peripheral sensitive neurons (of the IId Dogil's type). By means of experimental morphological and electrod physiological analyses performed in 36 dogs, a possible connection of intraenteric neurons of the IId Dogiel's type with the spinal cord is demonstrated, at least with in the level of 5-10 thoracic segments. The centripetal fibres from the jejunum go together with the intestinal, coeliac nerves, intranodular, white and grey connective branches of the sympathetic trunk and, further - with posterior and anterior roots of the cerebrospinal nerves. The coeliac nerves serve as an important collector of the sympathetic afferents along their way from the peritoneal cavity. A part of axons of the peripheral sensitive neurons end in presynaptic buds of a terminal type on the motoneurons in the prevertebral (coeliac plexus) and the paravertebral (thoracic sympathetic trunk) sympathetic ganglia accepting the positoin of the afferent link in the systems of extracentral reflex arcs. Owing to this sign, sensitive cells of the IId Dogiel's type are justly named "sympathetic afferent neurons". Elements of the peripheral (sympathetic) afferent system are remarkable for their diffuse localization, that is corroborated by: an extreme dispersity of trophic centers (cells of the IId Dogiel' type); their axons form synapses with motor cells of numerous and sometimes unstable, individually changeable sympathetic ganglia; transfer of the centripetal sensitive fibres into the spinal cord via posterior and anterior roots.     

Participation of alpha and beta adrenoreceptors in facilitating and inhibiting the action of the sympathetic nervous system in parasympathetic bradycardia

Electrical stimulation of the distal vagal cervical end in urethane chloralose anesthetized cats caused bradycardia that could be both enhanced and inhibited during sympathetic activation. Sympathetic activation was induced by electrical stimulation of the sympathetic outflow of the spinal cord at the level of Th 1-Th 3 in pitched cats or by an intravenous injection of tyramine. It has been proved pharmacologically that alpha-adrenoceptors are involved in potentiation. The inhibitory influences are realized via both alpha- and beta-adrenoceptors.     

Development of the thoracic duct in the prenatal period of human ontogeny

In 40 series of histological sections performed in human embryos and prefetuses from 4 up to 20 weeks of development, as well as in 20 corpses of fetuses and stillborns, it has been stated that the anlage of the thoracic duct appear in 6-7-week-old fetuses as lymphatic clefts surrounded with mesenchymal cells that are situated near large veins in the areas of the most active morphogenesis. Connecting with each other, the clefts form the jugular and retroperitoneal lymph sacs and a well branching network of canals. From the latter, on the 7th-8th week of development a plexus of lymph vessels appear, and later on (on the 8th-9th week)--bilaterally situating trunks of the thoracic duct. Further development of the thoracic duct is connected with the lymph nodes formation, their germs appear on the 9th-10th week along the course of the left trunk, as well as along the ductal branches and anastomoses. The formation of the lymph nodes results in reduction of some trunks and plexuses of the thoracic duct. Owing to this, its form in 14-15-week-old prefetuses resembles the one in newborns. Disturbances in the formation processes of the lymph nodes along the course of the reducing ductal areas, as well as their formation along the course of its main trunk can result in various structural variants of the thoracic duct in children and grown-up persons. Histogenesis of the thoracic duct wall and formation of the lymph nodes are not completed by birth.     

Changes in the blood vessels, spinal cord neurocytes, pia mater and spinal ganglia in chronic stimulation of the sympathetic trunks

Taking into account the data concerning disturbances in blood supply of the spinal cord as a response to irritation of the sympathetic trunks, the experimental morphological investigation has been performed on rabbits. By means of the injection technique and staining of neurocytes, changes in the spinal cord, in the spinal nodes and in the pia mater have been studied at chronic irritation of the lumbar nodes of the sympathetic trunk. Certain degenerative changes have been revealed in nervous cells and also phenomena of the spinal cord ischemia, decreasing contacts between the nervous cells and the capillaries surrounding them. As the authors believe, these data can be used by clinicians for revealing pathological mechanisms of the spinal cord ischemia as a result of chronic irritation of the sympathetic trunk.     

Origin and development of the catecholamine-storing cells of the human fetal carotid body

Summary The carotid bifurcation areas of 25 human fetuses aged from 8 to 22 weeks were studied using the formaldehyde-induced fluorescence method. A long process from the sympathetic trunk reached the area at the age of 8 weeks contacting with the carotid body primordium. Brightly fluorescent cells can be seen both in the carotid body and in the ganglionic process. Migration of these cells from the sympathetic trunk to the carotid body is suggested. The connection from the sympathetic trunk to the carotid body totally disappeared after the tenth week, leaving no fluorescent elements between these two. Control electron microscopy and light microscopy were performed to identify the fluorescent and nonfluorescent components of the human fetal carotid body.     

Effect of Midthoracic Spinal Cord Constriction on Catalytic Nitric Oxide Synthase Activity in the White Matter Columns of Rabbit

The distribution and changes of catalytic nitric oxid synthase (cNOS) activity in the dorsal, lateral and ventral white matter columns at midthoracic level of the rabbit's spinal cord were studied in a model of surgically-induced spinal cord constriction performed at Th7 segment level and compared with the occurrence of nicotinamide adenine dinucleotide phosphate diaphorase expressing and neuronal nitric oxide synthase immunoreactive axons in the white matter of the control thoracic segments. Segmental and white-column dependent differences of cNOS activity were found in the dorsal (141.5 ± 4.2 dpm/m protein), lateral (87.3 ± 11.5 dpm/m protein) and ventral (117.1 ± 7.6 dpm/m protein) white matter columns in the Th5-Th6 segments and in the dorsal (103.3 ± 15.5 dpm/m protein), lateral (54.9 ± 4.9 dpm/m protein), and ventral (86.1 ± 6.8 dpm/m protein) white matter columns in the Th8-Th9 segments. A surgically-induced constriction of Th7 segment caused a disproportionate response of cNOS activity in the rostrally (Th5-Th6) and caudally (Th8-Th9) located segments in both lateral and ventral white matter columns. While a statistically significant decrease of cNOS activity was detected above the constriction site in the ventral columns, a considerable, statistically significant increase of cNOS activity was noted in the white lateral columns below the site of constriction. It is reasoned that the changes of cNOS activity may have adverse effects on nitric oxide (NO) production in the white matter close to the site of constriction injury, thus broadening the scope of the secondary mechanisms that play a role in neuronal trauma.     

Morphological changes in nodes of the celiac plexus as affected by extensive abdominal surgery

Experiments on 163 dogs were made to study the time course of histological and ultrastructural changes in celiac plexus nodes after resection of the two-thirds of the stomach as well as after some other large operations on the abdominal organs (economic gastric resection, cholecystectomy, resection of the small intestine). It has been demonstrated that since the first days after operation the gangliocytes and neuroglial cells of celiac plexus nodes manifested histological changes detectable at light and electron microscopy levels. These changes were largely reversible in nature despite destructive processes eventuating in the death of some gangliocytes, pericapsular gliocytes and neurolemmocytes. The most overt changes were observed towards the first week after operation, the number of neurons with reversible changes amounting to 42% and that having the signs of destruction to 9.9%. At the later stages the intensity of the histological changes was noticeably reduced. Analogous data were obtained during studies of the time course of the histological changes after other above-indicated operations. However, the intensity of the changes was substantially less than that seen after resection of the two-thirds of the stomach. The evidence obtained allows the conclusion that the pathological structural changes that develop in the celiac plexus after resection of the two-thirds of the stomach play one of the leading parts in the pathogenesis of the post-gastroresection syndrome.     

Depletions in the cervical and thoracolumbar sympathetic system following removal of neural crest from the embryo of Chelydra serpentina

Neural crest and dorsal neural tube of cervical and thoracolumbar levels were removed from embryos of Chelydra serpentina at stages ranging from 8 to 18 somites. Extirpation extended from the levels of the last four somites posteriorly around the neurenteric canal. Deficiencies in sensory and sympathetic ganglia occurred. Motor roots of the associated spinal nerves differentiated. In the absence of postganglionic neurons, the preganglionic fibers form a neuron-free plexus in the thoracolumbar region. Some observations in the cervical region indicate that the postganglionic neurons depend on preganglionic fibers for their differentiation. The cortex of the adrenal gland formed without related medulla in appropriate experiments. The normal morphology of the sympathetic trunks is illustrated. Superficial and deep cervical sympathetic trunks are described. The latter ascends the neck in a paravertebral position. Along its course are segmental ganglia and rami communicantes; it terminates by joining the medial branch of the superficial sympathetic trunk rostral to the ninth cranial nerve.     

Increased superoxide levels in ganglia and sympathoexcitation are involved in sarafotoxin 6c-induced hypertension

Endothelin (ET) type B receptors (ET(B)R) are expressed in multiple tissues and perform different functions depending on their location. ET(B)R mediate endothelium-dependent vasodilation, clearance of circulating ET, and diuretic effects; all of these should produce a fall in arterial blood pressure. However, we recently showed that chronic activation of ET(B)R in rats with the selective agonist sarafotoxin 6c (S6c) causes sustained hypertension. We have proposed that one mechanism of this effect is constriction of capacitance vessels. The current study was performed to determine whether S6c hypertension is caused by increased generation of reactive oxygen species (ROS) and/or activation of the sympathetic nervous system. The model used was continuous 5-day infusion of S6c into male Sprague-Dawley rats. No changes in superoxide anion levels in arteries and veins were found in hypertensive S6c-treated rats. However, superoxide levels were increased in sympathetic ganglia from S6c-treated rats. In addition, superoxide levels in ganglia increased progressively the longer the animals received S6c. Treatment with the antioxidant tempol impaired S6c-induced hypertension and decreased superoxide levels in ganglia. Acute ganglion blockade lowered blood pressure more in S6c-treated rats than in vehicle-treated rats. Although plasma norepinephrine levels were not increased in S6c hypertension, surgical ablation of the celiac ganglion plexus, which provides most of the sympathetic innervation to the splanchnic organs, significantly attenuated hypertension development. The results suggest that S6c-induced hypertension is partially mediated by sympathoexcitation to the splanchnic organs driven by increased oxidative stress in prevertebral sympathetic ganglia.     

Nerves and nerve plexuses of the human vertebral column

The origin, distribution, and termination pattern of nerves supplying the vertebral column and its associated structures have been studied in the human fetus by means of an acetylcholinesterase whole-mount method. The vertebral column is surrounded by ventral and dorsal nerve plexuses which are interconnected. The ventral nerve plexus consists of the nerve plexus associated with the anterior longitudinal ligament. This longitudinally oriented nerve plexus has a bilateral supply from many small branches of the sympathetic trunk, rami communicantes, and perivascular nerve plexuses of segmental arteries. In the thoracic region, the ventral nerve plexus also is connected to the nerve plexuses of costovertebral joints. The dorsal nerve plexus is made up of the nerve plexus associated with the posterior longitudinal ligament. This nerve plexus is more irregular and receives contributions only from the sinu-vertebral nerves. The sinu-vertebral nerves originate from the rami communicantes and, in the cervical region, also from the nerve plexus of the vertebral artery. Thick and thin sinu-vertebral nerves are found. Most frequently three types of thick sinu-vertebral nerves are observed, i.e., ascending, descending, or dichotomizing ones. Finally, the distribution of the branches of the ventral and dorsal nerve plexuses and of the sinu-vertebral nerves is described.