Studies on intra-arterial cushions. IV. Perivascular nerve plexuses of ramifying arteries with intraluminal cushions at the branching points

Periarterial nerve plexuses were studied at branching points of arteries with intraluminal cushions. Serial sections were prepared from mouse kidney, pancreas and tongue, and studied by means of catecholamine fluorescence and staining for acetylcholinesterase. The periarterial nerve plexuses did not show any peculiarities at the branching points. The intraluminal cushions, as well as the tunica media of both the parent trunk and the collateral branches, were found to be free of vegetative nerves. It is concluded that the shape of intra-arterial cushions is passively altered, following the alterations of vascular geometry, and not in response to direct nervous stimulation.     

The intermediate nerve and its place in the system of cranial nerves

The intermediate nerve (IN) in embryogenesis of man, cat and white rat is formed similarly. From the common with the VIII cranial nerve anlage the geniculum node, the vestibular and cochlear ganglia are emerged. A separated root of the IN connects the geniculum node with the nuclei, situating in the CNS. From the geniculum node main branches of the IN get off: the greater petrosal nerve and the cord of the tympanum, its fibers in the temporal bone canal run in the facial nerve trunk. In the periphery the IN branches unite with other cranial nerves, make connections with branches of vegetative (parasympathetic) ganglia and plexuses. They spread along a large territory, forming a system of parasympathetic innervation in the area of the head and ensuring with specific nervous apparatuses the gustatory organ. It is expedient to select the IN into an independent cranial nerve and confirm it the number of the regular pair.     

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.     

Articular cartilage in the knee joint of the African elephant, Loxodonta africana, Blumenbach 1797

Knee joints of one adult and three juvenile African elephants were dissected. The specific features of the articular cartilage with particular reference to matrix components were studied by light and electron microscopy and immunohistochemistry. The elephant knee joint cartilage contains an unusually low concentration of proteoglycans resulting in rather eosinophilic staining properties of the matrix. The very thick collagen fibers of the cartilage possibly represent collagen I. Except for the different thickness of cartilage at the weight-bearing surfaces of femur (approximately 6.7 mm) and tibia (approximately 11.2 mm) in juvenile elephants, light and electron microscopy did not reveal distinct topographical differences in cartilage structure, perhaps because of the high congruency of the articulating surfaces and resulting uniform load distribution in the knee. The number of cell profiles per section area of both femoral (approximately 950 cell profiles/mm(2)) and tibial cartilage (approximately 898 cell profiles/mm(2)) was low, indicating excessive matrix production by the chondrocytes during cartilage development. These unique properties could be a result of the enormous compressive load resting on the elephant knee. Maintenance of the equilibrium between biological function and resistance to compression seems to be crucial in the elephant knee joint cartilage. Any disturbance that interferes with this equilibrium appears to lead to arthrotic alterations, as particularly seen in captive elephants.     

Characteristic pattern of monoaminergic nerve fibers in the pineal organ of the monkey,Macaca fuscata

Summary Monoaminergic nerve fibers were studied in the pineal organ of the monkey, Macaca fuscata, by use of fluorescence and immunohistochemical procedures. Abundant formations of noradrenergic nerve fibers were observed in the pineal organ. They entered the parenchyma in the form of several coarse bundles via the capsule in the distal portion of the organ and spread throughout the organ after branching into smaller units. The density of the autonomic innervation decreased gradually toward the proximal portion of the organ. In the distal portion, numerous nerve fibers formed perivascular plexuses around the blood vessels and some fibers ran as bundles unrelated to the blood vessels in the stroma. Fine varicose fibers and bundles derived from these plexuses penetrated among the pinealocytes. However, only a few intraparenchymal fluorescent fibers were detected in the proximal third of the gland. With the use of serotonin antiserum serotonin-immunoreactive nerve fibers were clearly restricted to the ventroproximal part of the pineal organ. Although the somata of the pinealocytes showed intense immunoreactivity, their processes were not stained. In one exceptional case, clusters of pinealocytes displaying very intense immunoreactivity were found in an area extending from the distal margin of the ventral portion of the pineal stalk to the proximal portion of the pineal organ proper; these cells were bipolar or multipolar and endowed with well-stained processes.     

Structure and function of spiny lobster ligamental nerve plexuses: Evidence for synthesis,storage, and secretion of biogenic amines

Three pairs of ligaments support not only the heart of spiny lobsters but also ligamental nerve plexuses, the complex terminal aborizations of segmental nerves. Segmental nerves 1–4 project from the thoracic ganglia into the pericardial cavity and ultimately ramify along the strands of the anterior, medial, and posterior ligaments. In each branch, a core of large axons sends fibers to terminate in a surrounding cortex of fine and varicose secretory processes. Electron micrographs reveal at least five distinct populations of granule-filled neuronal profiles, many with vesicles clustered at membrane thickenings adjacent to the epineural sheath. The ligamental nerve plexuses synthesize and accumulate octopamine, dopamine, 5-HT, and acetylcholine. Octopamine and 5-HT are predominant, comprising 33% and 65%, respectively, of the synthetic activity devoted to the four amines. Thus, the anatomy, ultrastructure, and neurochemistry of the ligamental nerve plexuses establishes their homology with the pericardial organs of other Crustacea. Octopamine and 5-HT are released by a Ca⁺⁺-dependent mechanism upon electrical stimulation of preterminal nerve trunks, and, in vivo, would be swept immediately through ostia into the heart. These observations, when considered with known effects of octopamine and 5-HT on crustacean cardiac activity, neuromuscular transmission, muscle tension, and cyclic AMP metabolism provide a strong case for hormonal actions at target sites throughout the animal. Segmental nerve processes in the dorsal nerve trunk ramify into a plexus around the dorsal nerve apparatus, a small muscular bulb that lies recessed in the cardiac surface. The dorsal nerve, carrying excitatory and inhibitory input to the cardiac ganglion directly through the bulb's hollow interior. The apparatus synthesizes and contains acetylcholine and the three amines mentioned above. In situ, it may beat rhythmically out of phase with the heart.     

Autonomic nerves terminating on smooth muscle cells of vessels in the pineal organ of various mammals

The significance of autonomic nerves reaching the pincal organ was already investigated in connection to the innervation of pinealocytes and mediating light information from the retina for periodic melatonin secretion. In earlier works we found that some autonomic nerve fibers are not secretomotor but terminate on arteriolar smooth muscle cells in the pineal organ of the mink (Mustela vison). Studying in serial sections the pineal organ of the mink and 15 other mammalian species in the present work, we investigated whether similar axons of vasomotor-type are generally present in the wall of pineal vessels, further, whether they reach the organ via the conarian nerves or via periarterial plexuses. In all species investigated, axons of perivasal nerve bundles were found to form terminal enlargements on the smooth muscle layer of pineal arterioles. The neuromuscular endings contain several synaptic and some granular vesicles. Axon terminals are also present around pineal veins. In serial sections, we found that the so-called conarian autonomic nerves reach the pineal organ alongside pineal veins draining into the great internal cerebral vein. Similar nerves present near arteries of the arachnoid enter the pineal meningeal capsule and septa by arterioles, both perivenous and periarterial nerves form terminals of vasomotor-type. The arteriomotor and venomotor regulation of the tone of the vessels of the pineal organ may serve the vascular support for circadian and circannual periodic changes in metabolic activity of the pineal tissue.     

Cholinesterase activity in quail primary lymphoid organs

The present histochemical study was carried out to analyze the distribution and topography of acetylcholinepositive nerve fibers in the thymus and bursa of Fabricius of quails. The AChE-positive nerve fibers were demonstrated by direct thiocholine histochemical method. Nerve fibers present in the thymuses form periarterial nerve plexuses located mostly in the interlobular septa and on the cortico-medullary junction. Vessels-independent nerve fibers occur also in the parenchyma of thymic medulla, but rarely in parenchyma of the cortex. Within the connective tissue between the bursa of Fabricius and the wall of proctodeum we observed conspicuous AChE-positive ganglia, often in close relationship to greater arteries. Within the wall of bursa of Fabricius, AChE-positive nerve fibers create nerve plexuses around arteries. We observed a close relationship between lymphoid follicules in bursal submucosa and mucosa and AChE-positive nerve fibers. Nerve fibers create a ring around lymphoid follicles, but do not penetrate into the germinal center of the follicle. Arteries inside quail thymuses and bursae of Fabricius contain rich AChE-positive nerve plexuses, when compared to the veins, which have a very poor presence of AChE-positive nerves. According to lesser presence and decreased density of AChE-positive nerve fibers in older animals, we described age-dependent changes in both quail primary lymphoid organs.     

Distribution and origin of vasoactive intestinal polypeptide (VIP)-immunoreactive,acetylcholinesterase-positive and adrenergic nerves of the cerebral arteries in the bent-winged bat (Mammalia: Chiroptera)

Summary The overall distribution and origins of vasoactive intestinal polypeptide (VIP)-immunoreactive (IR), acetylcholinesterase (AChE)-positive and adrenergic nerves in the walls of the cerebral arteries were investigated in the bent-winged bat. VIP-IR and AChE-positive nerves innervating the bat cerebral vasculature appear to arise mainly from VIP-IR and AChE-positive cell bodies within microganglia found in the nerve bundle accompanying the sympathetic nerve bundle within the tympanic cavity. These microganglia, as well as the nerve bundle containing them, do not emit catecholamine fluorescence, suggesting that they are of the cranial parasympathetic outflow, probably the facial or glossopharyngeal one. The axons from VIP-IR and AChE-positive microganglia run intermingled with sympathetic adrenergic nerves in the same thick fiber bundles, and reach the cranial cavity through the carotid canal. In addition, some of the VIP-IR fibers innervating the vertebro-basilar system, at least the basilar artery, originate from VIP-IR nerve cells located in the wall of this artery.The supply of VIP-IR fibers to the bat major cerebral arteries is the richest among mammals that have been studied, and differs from other mammals in that it is much greater in the vertebro-basilar system than in the internal carotid system: plexuses of VIP-IR nerves are particularly dense along the walls from the posterior ramus to posterior cerebral and basilar arteries. Small pial and intracerebral arteries of the vertebro-basilar system, especially those of the posterior cerebral artery which supply most parts of the diencephalon and cerebrum, are also richly innervated by peripheral VIP-IR fibers. This pattern corresponds well with the innervation pattern of adrenergic and AChE-positive nerves.     

大鼠食管胸段，腹段乙酰胆碱酯酶阳性神经的配布

大鼠食管胸段和腹段壁内乙酰胆碱酯酶（ＡＣｈＥ）阳性神经存在于神经束和分支的粗细神经纤维内,也见于外膜丛,肌间丛,粘膜下丛和粘膜肌内。食管肌层内ＡＣｈＥ阳性神经纤维多而密集,而食管腹段肌内尤为丰富,肌间神经纤维末梢分布于肌束表面,可能与控制肌纤维活动有关;分布于肌内,粘膜下层和上皮基部的ＡＣｈＥ阳性神经中,尚含有内脏感觉神经纤维。食管壁的肌间丛和粘膜下丛内散在有多极形和卵园形的ＡＣｈＥ阳性神经元,在食管腹段内数多,而以中小型神经元为主。     

Study on the innervation of the pancreas of the rat.

The pancreas of the adult rat is examined by the silver impregnation method. The intrapancreatic nerves form the following three plexuses: periacinous, periinsular and perivascular; anastomosing fibers are presented between the three plexuses. Sympathetic ganglia as well as parasympathetic nerve cells are met with in association and in close proximity to the islet tissue. The significance of the double innervation of the islet tissue is discussed.     

人十二指肠血管活性肠肽能P物质能神经分布的研究

本文采用免疫组织化学ＡＢＣ法研究血管活性肠肽（ＶＩＰ） 能神经和Ｐ物质（ＳＰ） 能神经在人十二指肠壁内的分布。结果显示： ＶＩＰ能和ＳＰ能神经纤维和神经元均呈棕褐色; ＶＩＰ能神经纤维遍布肠壁各层,ＳＰ能神经纤维主要分布于肌层和神经丛; ＶＩＰ能和ＳＰ能神经元见于肌间和粘膜下神经, 尤以后者为多, 但形态特点不同; 在肌间神经丛, ＳＰ能神经元比ＶＩＰ能神经元多。粘膜内可见ＶＩＰ能和ＳＰ能神经元, 多单个分布在粘膜肌层内。结果表明： １ＶＩＰ能和ＳＰ能神经在人十二指肠壁内分布有差异。２粘膜内存在ＶＩＰ能和ＳＰ能神经元     

Presence and distribution of serotonin immunoreactivity in the cyprids of the barnacle Balanus amphitrite

In this work, the presence and distribution of serotonin in the cyprid of the barnacle Balanus amphitrite were investigated by immunohistochemical methods. Serotonin-like immuno-reactive neuronal cell bodies were detected in the central nervous system only. Various clusters of immunoreactive neuronal cell bodies are distributed in the brain (protocerebrum, deutocerebrum, optical lobes), and at least, four pairs of neuronal cell bodies were detected in the centrally positioned neuropil of the posterior ganglion. Rich plexuses of immunoreactive nerve fibers in the neuropil area were also observed. Furthermore, bundles of strongly immunoreactive nerve fibers surrounding the gut wall were localized, and immunoreactive nerve terminals in the antennules and compound eyes were observed. These data demonstrate the presence of a serotonin-like immunoreactive substance in the barnacle cyprids; furthermore, its immunolocalization in the cephalic nerve terminals allows us to postulate the involvement of this bioactive molecule in substrate recognition during the settlement process.     

Peptide-containing neurons intrinsic to the gut wall

Summary Nerve fibers containing substance P, VIP, enkephalin or somatostatin are numerous in the porcine gut wall. They are particularly numerous in the submucosal and myenteric plexuses where peptide-containing cell bodies are also observed. Peptide-containing nerve fibers occur also in the vagus nerves, suggesting that the gut receives an extrinsic supply of peptidergic nerves. The extrinsic contribution to the peptide-containing nerve supply of the gut wall has not yet been quantitatively assessed. In an attempt to clarify this question pigs were subjected to bilateral subdiaphragmatic vagotomy. Another group of animals was subjected to complete extrinsic denervation by autotransplantation of a jejunal segment. The pigs were killed at various time intervals after the operations; the longest time interval studied was four months. Following vagotomy the innervation pattern of the jejunum appeared completely unaffected. Following complete extrinsic denervation the adrenergic nerve fibers disappeared, while peptide-containing and acetylcholinesterase-positive nerve fibers remained apparently unaltered. This was confirmed chemically in the case of substance P.The motor activity of smooth muscle from the jejunum was studied in vitro. At low stimulation frequencies the smooth muscle from control jejunum responded by relaxation; upon cessation of stimulation a contraction occurred. With increasing stimulation frequencies the duration of the relaxation decreased; at high frequency stimulation only a contraction was recorded. In the autotransplant low frequency stimulation induced no or only a weak relaxation; high frequency stimulation induced contraction. After cholinergic and adrenergic blockade, the muscle responded with relaxation at all frequencies; the response was similar in innervated and denervated specimens. On the whole, the effects of extrinsic denervation on the motor activity of smooth muscle from porcine jejunum were minor, possibly reflecting the high degree of autonomy of the gut.     

Cutaneous and subcutaneous sensory receptors of the hagfish Myxine glutinosa with special respect to the trigeminal system

The integument of the hagfish Myxine glutinosa is described with respect to the topography and the fine structural organization of the dermal and hypodermal nerve fiber plexus. Both nerve fiber plexuses contain small ganglion cells with axodendritic and axosomatic synapscs. The six barbels of the head (4 nasal and 2 oral barbels) are supplied with about 5600 afferent trigeminal nerve fibers via the right and left ophthalmic nerve. With respect to the topography of the sensory nerve terminals in the barbels different types of receptors are termed the external cuff receptor, internal cuff receptor, and perichondrial receptor. Free nerve terminals occur within the epidermal layer, especially at the tip region of the barbels and in the glassy membrane of the dermis. The hypodermal edge receptor organ extends from the ventral nasal barbel to the oral barbel. A mechanoreceptive function of the different receptor types is discussed. The innervation pattern of the barbel is similar to the innervation of the mammalian sinus hair. In this context, the barbel is a highly differentiated receptor organ able to explore the nearest surroundings with high stereognostic perception. The ganglion cells of the skin seem to represent a part of the peripheral autonomic nervous system, which is involved in the control of secretion mechanisms.     

A continuum model of elephant trunks

A continuum model is presented that relates the trunk parameters of loading, geometry, and muscle structure to the necessary conditions of static equilibrium. Linear theory for stress-strain behavior is used to describe an elephant trunk for an incremental displacement as the animal slowly lifts a weight at the trunk tip. With this analysis and experimental values for the trunk parameters, the apparent trunk stiffness Ea is estimated for the living animal. For an Asian elephant with a maximum compression strain of 33 percent, Ea is of the order of 10(6) N/m2. The continuum model is quite general and may be applied to similar nonskeletal appendages and bodies of other animals.     

The nervous system in planarians: Peripheral and gastrodermal plexuses,pharynx innervation,and the relationship between central nervous system structure and the acoelomate organization

The Champy-Maillet osmium tetroxide-zinc iodide technique and a new method using azur B-sodium thioglycolate were used to study the general nervous tissue structure in planarians. A subepidermal and a submuscular nerve plexus, partially reported by earlier authors, are described, and a gastrodermal plexus is reported for the first time in triclads. The possible functions for each one of these plexuses are discussed. By the Champy-Maillet method, the innervation within the parenchyma appears as an array of numerous single nerve fibers that course between the parenchyma cells making apparent synaptic contacts. The pharynx has outer and inner nerve nets similar in structure to the submuscular nerve plexus. Both nerve nets are connected to each other by radial nerves. The central nervous system has a sponge-like structure with many lacunae filled with cell bodies, dorso-ventral muscle fibers, parenchymal cell processes and excretory ducts. The existence of this sponge-like nervous tissue structure is discussed in relation to the still incomplete centralization of the nervous tissue in these organisms, to the lack of a true vascular system and to the acoelomate level of organization. A comparison with the nervous tissue structure of more advanced groups like polyclads and nemertines is suggested.     

Neuronal distribution and subcellular localization of HCNP-like immunoreactivity in rat small intestine

A novel peptide, hippocampal cholinergic neurostimulating peptide (HCNP), originally purified from young rat hippocampus, affects the development of specific cholinergic neurons of the central nervous system in vitro. In this study, HCNP-like-immunoreactive nerve processes and nerve cell bodies were identified by electron microscopic immunocytochemistry in the rat small intestine. Labeled nerve processes were numerous in the circular muscle layer and around the submucosal blood vessels. In the submucosal and myenteric plexuses, some HCNP-like-immunopositive nerve cell bodies and nerve fibers were present. The reaction product was deposited on the membranes of various subcellular organelles, including the rough endoplasmic reticulum, Golgi saccules, ovoid electron-lucent synaptic vesicles in axon terminals associated with submucosal and myenteric plexuses, and the outer membranes of a few mitochondria. The synaptic vesicles of HCNP-like-positive terminals were 60–85 nm in diameter. The present data provide direct immunocytochemical evidence that HCNP-like-positive nerve cell bodies and nerve fibers are present in the submucosal and myenteric plexuses of the rat small intestine. An immunohistochemical light microscopic study using mirror-image sections revealed that in both the submucosal and myenteric ganglia, almost all choline acetyltransferase (ChAT)-immunoreactive neurons were also immunoreactive for HCNP. These observations suggest (i) that HCNP proper and/or HCNP precursor protein is a membrane-associated protein with a widespread subcellular distribution, (ii) that HCNP precursor protein may be biosynthesized within neurons localized in the rat enteric nervous system, and (iii) that HCNP proper and/or HCNP precursor protein are probably stored in axon terminals.