Adrenergic innervation of the gills, pulmonary arterial plexus, and dorsal aorta in the neotenic salamander, Ambystoma tigrinum

The presence of adrenergic innervation was investigated in four different vascular segments of the neotenic tiger salamander, Ambystoma tigrinum, by histofluorescent staining for catecholamines. The segments were the respiratory section of the gill, the branchial shunt vessels, a vascular plexus in the pulmonary artery, and the dorsal aorta. No adrenergic fibers were detected in the respiratory section of the gill or the pulmonary arterial plexus. In contrast, the branchial shunt vessels contained both adrenergic varicosities and catecholamine-containing cell bodies. These cells resemble Type I cells of the mammalian carotid body and amphibian carotid labyrinth. Adrenergic innervation of the dorsal aorta was sparse and restricted to the adventitia. The results suggest that adrenergic nerves may directly regulate blood flow in the gill, and thus gas exchange, by controlling vascular resistance of the branchial shunts. The contractile state of the dorsal aorta may also be under adrenergic control. In addition, it is suggested that the adrenergic cells of the branchial shunts may serve a receptor function in being sensitive to arterial blood gases.     

A histochemical study of the innervation of the cerebral blood vessels in the domestic fowl

Summary Adrenergic and cholinergic nerves innervating the cerebral arteries of the domestic fowl were examined by specific histochemical techniques.The adrenergic nerve plexuses of the cerebral carotid system are markedly denser than those of other vertebrates observed by similar techniques. They form longitudinally elongated meshworks of fine fibres in the vascular wall of the arterial branches. Those innervating the vertebro-basilar system are less dense and more elongated, and, as the size of the artery diminishes, the fibres of the plexus become coarser. In the small pial and parenchymal arteries they are reduced to a few fibres running parallel to, or spiralling around the vascular axis.The cholinergic nerve plexuses are not as dense as the adrenergic system. The acetylcholinesterase activity is very weak, except in the plexuses innervating the cerebral carotid artery and the proximal portion of the anterior and posterior rami. In the vertebro-basilar system, a few thick nerve bundles run alongside the blood vessels of the vertebral and basilar arteries. Cholinergic nerves enter the cranial cavity along the internal carotid, the vertebral and possibly the cerebro-ethmoidal arteries.Intracerebral capillaries and some arterioles are not innervated with cholinergic and adrenergic fibres of peripheral origin, but with ones arising from parenchymal nerve cells.     

The origin and distribution of adrenergic nerve fibres in the guinea-pig colon

Summary A detailed study of the origin and distribution of sympathetic fibres in the distal colon of the guinea-pig has been made using the fluorescent histochemical method for localizing catecholamines. The extrinsic adrenergic fibres of the colonie sympathetic nerves follow the inferior mesenteric artery and its branches to the colon. Some of the extrinsic adrenergic fibres are associated with the parasympathetic fibres of the pelvic nerves near the colon. Complete adrenergic denervation follows the removal of the inferior mesenteric ganglion or the destruction of the nerves running with the inferior mesenteric artery.No fluorescent fibres, other than those associated with blood vessels, were observed in air-dried stretch preparations of the isolated longitudinal muscle. However, a substantial number of varicose, terminal fibres, not associated with blood vessels, were observed in the circular muscle. Some varicose fibres, apart from those associated with ganglion cells, were observed in the myenteric plexus. These fibres were seen in the bundles of nerves running between the nodes of the plexus and also as single fibres which branched from the plexus to end in areas free of ganglion cells.Three plexuses of adrenergic nerve fibres have been distinguished in the submucosa: a dense plexus of terminal fibres innervating both the veins and arteries; a plexus consisting of innervated nodes of ganglion cells, connected by bundles of fluorescent and non-fluorescent nerves; and a plexus of varicose and non-varicose fibres, which is not associated with ganglion cells. Some groups of ganglion cells in the submucosa were without adrenergic innervation.A plexus of varicose fibres forms a meshwork in the lamina propria of the mucosa. The muscularis mucosae is sparsely innervated. Most of the blood vessels in the mucosa are not associated with adrenergic fibres.     

Fluorescence histochemical study on regional differences in the sympathetic nerve supply of the choroid plexus from various laboratory animals

Summary The adrenergic nerve supply of the choroid plexus in all four ventricles was studied by the Falck-Hillarp histofluorescence technique in nine different species, and the noradrenaline concentration in whole plexus tissue was determined by a radioenzymatic method. The nerve density was usually in the order: third > lateral > fourth ventricular plexuses. Plexuses of the pig and cat possessed the largest number of nerves; the innervation was intermediary in the baboon, guinea-pig, rat, rabbit and hamster, whereas only few fluorescent nerves were found in the cow and mouse plexuses. Sympathetic denervation showed an ipsilateral supply from the superior cervical ganglia to the lateral plexuses and a mixed contribution to the midline plexuses. The total noradrenaline concentration varied between 0.10 and 0.73 ng per mg protein.     

Ultrastructural immunocytochemical distribution of VIP-like immunoreactivity in dog ileum

The electron-immunocytochemical protein A-gold technique was employed to study the subcellular localization of vasoactive intestinal polypeptide-like material in dog ileum. The vasoactive intestinal polypeptide-like immunoreactivity was found within a population of large granular vesicles similar in structure in nerve varicosities of the myenteric plexus, the deep muscular plexus, the submucous plexus, the longitudinal muscular layer and the mucosa; none was found in nerve cell bodies. In the myenteric plexus, submucous plexus, the mucosa and the longitudinal muscular layer, varicosities containing similar large granular vesicles consistently remained unstained suggesting that within these plexuses morphologically indistinguishable by our technique large granular vesicles are not necessarily biochemically identical. In the deep muscular plexus, nearly all varicosities with large granular vesicles contained immunoreactivity for vasoactive intestinal polypeptide, but these varicosities often contained a few unstained large granular vesicles. This suggests that vasoactive intestinal polypeptide may share the same varicosity or the same vesicle with other neuropeptides present in this plexus (e.g., substance P or enkephalins) and that this plexus is a site where vasoactive intestinal polypeptide exerts its control over motility.     

Sources of the innervation of the carotid reflexogenic zone in representative reptiles

The investigation is dedicated to study sources of the carotid reflexogenic zone innervation in 43 tortoises (Testudo horsfieldi and Emys orbicularis). In 7 tortoises fine preparation of the vessels and nerves of the cervical area after V. P. Vorob'ev has been performed. In 13 animals descending branch of the glossopharyngeal nerve has been resected. In 4--the caudal ganglion of this nerve and in 9 tortoises the caudal ganglion of the vagus nerve have been resected. In 10 tortoises adrenergic nervous plexuses are studied after Falck-Govyrin method, and cholinergic ones--after Karnovsky-Roots. As demonstrate anatomical investigations, to the carotid reflexogenic zone of the tortoises, situating in the area of the common carotid artery base, the branches of the glossopharyngeal and of the vagus nerve approach. The experiments with resection of these nervous conductors demonstrate that by the end of 3 days after the operation myelin nervous fibers of various thickness are at the stage of granular decay. Cholinergic and adrenergic nervous fibers and plexuses are revealed histochemically in the carotid zone.     

Fluorescence microscopical and chemical characterization of the adrenergic innervation in mammalian liver tissue

Liver tissue from 12 different mammalian species was studied with a fluorescence histochemical technique for the cellular localization of amines (Falck-Hillarp technique) and with a chemical method for the determination of norepinephrine (HPLC-technique). Adrenergic nerve plexus were found in interlobular blood vessels derived from the portal vein and hepatic artery. Varicose adrenergic nerve fibres were, generally, seen to branch from the fibres around the blood vessels and to enter the liver parenchyma, where they formed a randomly distributed intralobular network. The density of these intralobular fibres showed marked species variation. Human liver and liver from the rhesus monkey, baboon, cynomolgus monkey and guinea pig showed a high density of parenchymal adrenergic nerves. Rabbit, cat, pig, cow and horse liver formed an intermediate group, having fewer varicose adrenergic nerve fibres but an unequivocal distribution of these nerves to the liver parenchyma. In rat and mouse liver no parenchymal innervation could be demonstrated. The density of the parenchymal innervation generally correlated with the concentration of norepinephrine in the liver tissue.     

Development of the blood-brain barrier to horseradish peroxidase in the chick embryo

Summary The development of the adrenergic sympathetic innervation of the rabbit choroid plexus system was studied prenatally and up to two months after birth by a combination of fluorescence histochemistry (formaldehyde and glyoxylic acid methods) and quantitative enzymatic determinations of noradrenaline. The first signs of adrenergic nerves are found in the plexus of the third ventricle within the first day after birth. Fluorescent fibres subsequently appear in the choroid plexuses of the lateral ventricles (five days post partum) and the fourth ventricle (two weeks post partum). During the following development nerve fibres grow along blood vessels to form a plexus located between small vessels and the overlying epithelium. The nerve plexus, with varicose axon terminals, is fully developed at three weeks post partum, and maturation is then established by an increase in the number of terminals within the network of axons. There is a good agreement between (a) the development of the fluorescent nerves and histochemically visible adrenergic innervation, and (b) the tissue level of noradrenaline in the various choroid plexuses. Against the background of available information on the development of the secretory functions in choroid plexus, it is concluded that possibilities for a sympathetic neurogenic influence on the formation of cerebrospinal fluid exist already a few weeks after birth.     

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.     

Adrenergic pattern of aorta and superior mesenteric arteries in young and senescent rats

The noradrenergic innervation of two portions of the aorta (thoracic and abdominal) was studied by the fluorescence method in rats belonging to two different age groups (3 and 28 months). Adrenergic fibres were clearly visible only in the abdominal tract of the aorta, and appeared to be more distinct and more numerous in young rats compared with the older ones. By contrast, the superior mesenteric artery was regularly found to possess a rich adrenergic plexus, even if catecholamines were more densely present in younger animals.     

Adrenergic and cholinergic components of the innervation of the arteries of the base of the bird brain

By means of Falck's and Koelle's methods adrenergic and cholinergic structures were studied in the arteries in the cerebral basis of blue rock pigeons and of hens, white leghorn stock. The number of nerve transmitters was estimated per 1 mm2 of the vessel surface. The arteries of the basis in pigeon brain are surrounded with developed adrenergic and cholinergic nerve plexuses, their density decreasing in the following order: nasal branch of the internal carotid artery, middle, nasal cerebral and basilar arteries. A little more cholinergic transmitters occur on the middle cerebral artery, while on the other vessels, concentration of cholinergic and adrenergic fibers is equal. In hens, the density in the arrangement of adrenergic nerve transmitters is higher in the nasal branch of the internal carotid and in the nasal cerebral arteries than in the basilar artery. At the same time, chromaffin cells forming numerous conglomerations in some places are found on the latter. In pigeons, the density of adrenergic fibers arrangement on the arteries of the cerebral basis is higher than in hens.     

Adrenergic innervation of the arteries of different diameters in the human and animal pia mater

The adrenergic nervous plexuses of the pial arteries from 450- to 50 micron in diameter have been studied in dogs, cats and humans from 4 age groups (22-44 years, 55-64 years, 65-74 years and 75-86 years old). It has been found that the decrease in the vessel diameter was accompanied by a marked decline in the absolute number of nervous fibers in the nervous plexuses, however the concentration of the nerve fibers has not revealed any significant differences between human arteries from 450 to 100 micron in diameter and animal arteries from 300 to 80 micron in diameter. The number of varicosities-thickness along the nerve fiber--was the greatest in 200-100 micron human arteries and in 80-60 micron animal arteries. With ageing, the number of varicosities in the adrenergic nervous plexus of human pial vessels decreased faster than in the nerve fibers.     

Morphofunctional changes in the adrenergic innervation of the major cerebral arteries during bilateral electrostimulation of the locus coeruleus

The intramural adrenergic nervous apparatus of cerebral arteries was studied in adult rabbits after 3-10 sessions of electrical stimulation of locus coeruleus. The activity of nerve structures was determined by estimating the density of adrenergic perivascular plexuses and by semi-quantitative cytophotometry of changes in the catecholamine content of nerve varicosities. The stimulation was followed by a 28.2 +/- 1.5% increase in adrenergic innervation density. while catecholamine content in perivascular nerve structures displayed a tendency to decrease. The problem of central effects on cerebral blood flow autoregulation is discussed.     

Blood collection from the tail of a rat

Techniques for blood collection from the rat include puncture of the heart, retro-orbital plexus, jugular vein, saphenous vein, tail blood vessels, carotid artery, abdominal aorta, and vena cava. Most techniques (except saphenous vein and tail blood vessel puncture) require anesthesia. The following discussion focuses on two methods of blood collection - ventral tail artery puncture and dorsal or lateral tail vein puncture.     

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.     

A histochemical study of the innervation of cerebral blood vessels in the snake

Summary Dual innervation of snake cerebral blood vessels by adrenergic and cholinergic fibres was demonstrated with the use of histochemical methods. Although the nerve plexuses are somewhat less dense, the essential features of innervation of the blood vessels are similar to those of mammals with the exception that the adrenergic plexuses are more prominent than the cholinergic plexuses. The major arteries of the cerebral carotid system have a rich nerve supply. However, the innervation is less rich in the basilar and poor in the spinal (vertebral) arteries. Although the arteries supplying the right side of head are poorly developed, three pairs of arteries, cerebral carotids, ophthalmics and spinals, supply the snake brain. The carotids and ophthalmics are densely innervated and are accompanied by thick nerve bundles, suggesting that the nerves preferentially enter the skull along those arteries. Some parenchymal arterioles are also dually innervated. Connection between the brain parenchyma and intracerebral capillaries via both cholinergic and adrenergic fibres was observed. In addition cholinergic nerve fibres, connecting capillaries and the intramedullary nerve fibre bundles, were noticed. Capillary blood flow may be influenced by both adrenergic and cholinergic central neurons. The walls of capillaries also exhibit heavy acetylcholinesterase activity. This may indicate an important role for the capillary in the regulation of intracerebral blood flow.     

Fluorescence microscopic study of the architecture and structure of an adrenergic network in the plexus myentericus (Auerbach), plexus submucosus externus (Schabadasch) and plexus submucosus internus (Meissner) of the porcine small intestine

The distribution of adrenergic fibres in the ganglionated plexuses of the porcine small intestine has been made on air-dried stretch preparations using the glyoxylic acid fluorescence method. Adrenergic fluorescent fibres occur in the ganglia and internodal strands of the three fundamental ganglionated plexuses: the myenteric plexus (Auerbach) and the two superimposed meshworks of the plexus submucosus , i.e. the plexus submucosus externus ( Schabadasch ) and the plexus submucosus internus (Meissner). The plexus Auerbach consists of densely glyoxylic acid induced fluorescent (GIF) elongated ganglia with in general a longitudinal axis running parallel to the circular muscle layer and large dense interconnecting fibre tracts with primary, secondary and tertiary subdivisions. In the ganglia, the fibres are varicose, forming large fluorescent 'baskets' which might be related to the occurrence of well defined enteric neurones. The plexus Schabadasch can be distinguished from the plexus Meissner by its size, strongly fluorescent ganglia and broad densely fluorescent internodal strands. The pattern of fluorescing ring-like formations at the margin and out of the nodes, clearly present in the Auerbach and Schabadasch plexuses, completely lack in the plexus Meissner, the latter being narrow-meshed with smaller fluorescent 'baskets', indicating that the corresponding neurones are smaller in size. In the ganglionic nodes of all three plexuses the axons display comparatively more varicosities than in the fibre tracts. Each of the three main ganglionated enteric plexuses are quite different with regard to the pattern of the adrenergic network both in the ganglia and in the strands.     

Canine myenteric, deep muscular, and submucosal plexus preparations of purified nerve varicosities: content and chromatographic forms of certain neuropeptides

Partially purified nerve varicosities prepared from canine small intestinal myenteric, deep muscular and submucosal plexuses were found to contain, by radioimmunoassay, gastrin-releasing polypeptide (GRP), substance P, Leu-enkephalin, Met-enkephalin, vasoactive intestinal polypeptide (VIP) and neurokinin A, but did not contain detectable amounts of neurokinin B. In all three plexus preparations, VIP was present in the highest concentration. In contrast to other species, GRP and the enkephalins were found to be present in relatively high concentrations in the submucosal plexus and GRP was present in low concentrations in the deep muscular plexus. Equal concentrations of substance P and neurokinin A were found in the myenteric and deep muscular plexus preparations but greater concentrations of substance P relative to neurokinin A were found in the submucosal plexus preparations. On reverse phase HPLC, a major peak of immunoreactivity occurred at the retention times of standard preparations for all six neuropeptides measured. Significant heterogeneity was found for GRP- and VIP-like immunoreactivity, especially in the submucosal plexus preparations. These partially purified canine small intestine nerve varicosity preparations may prove of value in studying release mechanisms for, and the posttranslational processing of, neuropeptides.     

Postnatal ontogenic development of the adrenergic innervation pattern in the rat portal vein

Summary The postnatal development of the adrenergic innervation pattern in the rat portal vein has been studied with the histochemical fluorescence method of Hillarp and Falck.Stretch preparations and transverse freeze-dried sections of intact portal veins were studied from rats during the first 5 weeks of life and from adult rats. Orientation of undifferentiated smooth muscle cells into two layers was observed at 4 days of age. Dominance of the thick outer longitudinal muscle layer was apparent at two weeks of age. A terminal adrenergic nerve plexus with some varicosities was restricted outside the media at the end of the first week. Ingrowth of penetrating non-terminal adrenergic nerve fibers through the longitudinal muscle layer occurred during the second week of age when the main terminal nerve plexus was developing between the two muscle layers. After 3 weeks of age the adult pattern of a two-dimensional adrenergic plexus between the muscle was established. In the adult rat pharmacological treatment with nialamide and noradrenaline revealed the thin, penetrating non-terminal adrenergic nerve fibers in the longitudinal muscle layer which were poorly visible otherwise.The present observations strongly indicate that the main adrenergic plexus between the two muscle layers emanates directly from the outer axonal plexus. These findings are discussed regarding possible trophic interactions between ingrowing sympathetic adrenergic vasomotor nerves and maturing vascular smooth muscle.Supported by grants from the Swedish Medical Research Council (grants No. 14X-2207, O4P-4173, 3884), Magn. Bergwall's Foundation, G. & M. Lindgren's Foundation, the Medical Faculty of University of Göteborg. The technical assistance of Miss Serney Bööj, Mr. Pär-Anders Larsson and Miss Ann Kjellstedt is gratefully acknowledged