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.     

Comparative histochemical distribution of nerve fibres storing noradrenaline and neuropeptide Y (NPY) in human ovary, fallopian tube, and uterus

Nerves containing noradrenaline were studied by formaldehyde-induced fluorescence and neuropeptide Y (NPY) was visualised by immunohistochemistry in the human ovary, Fallopian tube and uterus. All structures were richly supplied with noradrenergic fibres closely associated with the vascular and non-vascular smooth musculature. NPY-containing nerve terminals were consistently fewer, particularly in the ovary. The best developed nerve supply was found in the tubal isthmus and uterine cervix. Vessels were usually innervated by plexuses of nerves, containing NPY as well as noradrenaline. The discrepancy between the number of the two types of histochemically distinguishable nerves suggests that, if noradrenaline and NPY are co-localised in one and the same nerve, this is not a constant phenomenon in the human female reproductive tract.     

Quantitative analysis of the density and pattern of adrenergic innervation of blood vessels

Summary Automated quantitative image analysis (QIAF) was used to measure and compare the adrenergic nerve plexuses of 4 blood vessels from the guinea pig, demonstrated by glyoxylic acid fluorescence (GAF). The results showed considerable quantitative variation of plexus density, size of bundles, and numbers of varicosities. A range of alternative procedural and anatomical sources of variability were investigated and assessed. The carotid artery was found to have a dense plexus with more nerves than that of the mesenteric artery; the mesenteric vein and abdominal aorta had sparse plexuses. The carotid artery plexus, despite the density of its nerves, possessed only half the number of varicosities of the mesenteric artery plexus. This sparse varicosity population was shown to have a similar density to the varicosities demonstrated by QIAF in the scattered nerves of the mesenteric vein and abdominal aorta. QIAF confirmed visual estimates of adrenergic plexus density, and was able to demonstrate less obvious differences of nerve density and size, and varicosity populations, between the different plexuses studied. The method is applicable to stretch preparations and transverse sections of many adrenergically innervated tissues.     

Angiosomes of the brachial plexus: an anatomical study

This anatomical study analyzed the neurovascular relationships of the brachial plexus. Ten fresh cadaveric brachial plexuses were examined after injection of the arterial system. The vascular anatomical features of the brachial plexus were documented with microdissection after lead oxide/gelatin injection. The specimens were analyzed by using radiography (including digital subtraction techniques) and light-microscopic, macroscopic, and digital photography. Four angiosomes, based on the subclavian, axillary, vertebral, and dorsal scapular arteries, were observed. As noted in previous angiosome studies, connections between angiosome territories lay within tissues, in this case, nerve trunks. Nutrient vessels penetrated nerve trunks at points of branching within the brachial plexus, with a Y-shaped mode of division on entry. The vascular supply was markedly rich, often with true anastomotic connections occurring within the nerves. There was much variation in supply, depending on the vascular anatomical features of the subclavian artery.     

Avian enteric nerve plexuses

Summary The enteric nerve plexuses of the domestic fowl (Gallus domesticus) were investigated in sections and stretch preparations by means of the cholinesterase and glyoxylic acid fluorescence histochemical techniques. Cholinesterase-positive and varicose and non-varicose fluorescent nerve fibres were distributed at all levels of the gut in myenteric, submucosal, muscle and mucosal plexuses, and in a perivascular plexus. The density of the innervation and the detailed distribution of the nerves varied in different parts of the intestinal tract. All nerve plexuses appeared to be best developed in the rectum. Whereas the circular muscle coat contained a substantial number of nerves at all levels of the gut, the longitudinal coat was well innervated only in the rectum. The major portion of the mucosal plexus appeared to be associated with the intestinal glands. The nerve cell bodies were restricted to the myenteric and submucosal plexuses and were mainly cholinesterase-positive. Fluorescent ganglion cells were not observed. Pretreatment of stretch preparations with NADH: Nitro BT to stain ganglion cells showed that the majority of the cells were surrounded by a meshwork of fluorescent varicose fibres, although none of the fibres appeared to be associated with individual cells. The perivascular plexus was mainly associated with the arteries. The functional significance of the innervation is discussed.We would like to thank the British Council for financial support for Mr. H.A. Ali     

Potentiation by cocaine of relaxations of the guinea-pig colon caused by noradrenaline and by stimulation of adrenergic nerves.

The distal colon of the guinea-pig is relaxed by noradrenaline, by isoprenaline and by the stimulation of fibres running with the colonic nerves or intramurally. The relaxations in response to stimulation of the colonic nerves have a guanethidine-sensitive (adrenergic) and a guanethidine-insensitive (non-adrenergic) component. Cocaine causes a three-fold sensitization of the muscle to noradrenaline but no sensitization to isoprenaline. Cocaine increases the duration, but does not affect the amplitude, of the relaxation observed when adrenergic nerves are stimulated, and affects neither duration nor amplitude of the non-adrenergic response. The adrenergic nerve terminals lie in Auerbach's plexus, not in the longitudinal muscle. It is concluded that the sensitization to noradrenaline and the increases in durations of responses to adrenergic nerve stimulation are due to inhibition of catecholamine uptake into adrenergic nerves by cocaine. It appears that, even where the neuromuscular separation is large as it is in the colon, the concentration of exogenous noradrenaline at the receptors can be decreased by neuronal uptake, and the uptake mechanism can modify responses to nerve stimulation in vitro.     

Structural organization and neuropeptide distributions in the equine enteric nervous system: an immunohistochemical study using whole-mount preparations from the small intestine

The architecture and neurochemistry of the enteric nervous system was studied by use of whole-mount preparations obtained by microdissection of the horse jejunum. A myenteric plexus and two plexuses within the submucosa were identified. The external submucosal plexus lying in the outermost region of the submucosa had both neural and vascular connections with the inner submucosal plexus situated closer to the mucosa. Counts of neurones stained for NADH-diaphorase demonstrated the wide variation in size, shape and neurone content of individual ganglia in both the external and internal submucosal plexuses. The average number of cells/ganglion was similar in each plexus (about 25 cells). Immunoreactivities for galanin, vasoactive intestinal peptide and neuropeptide Y were observed in nerve cell bodies and fibres of each of the plexuses. Immunoreactivity for substance P was extensive and strong in nerve fibres of all plexuses but was weaker in cell bodies of the submucosal neurones and absent in the cell bodies of the myenteric plexus. Comparative quantitative analysis of immunoreactive cell populations with total cell numbers (enzyme staining) was indicative of neuropeptide colocalization in the external submucosal plexus.     

The brachial plexus of a capuchin monkey (Cebus capucinus)

Brachial plexuses of an adult female capuchin monkey (Cebus capucinus) were observed macroscopically. The main characteristic features of the organization of the plexus were as follows:Substantially the same organization was observed in the plexuses on both sides. The plexuses were formed by the union of the 5th–8th cervical nerves and the 1st thoracic nerve. The component from C5 contributed only to the superior posterior division; consequently the superior trunk in the strict sense was lacking. The medial cord was a peripheral extension of the inferior anterior division and formed a common trunk with the lateral root of the median nerve. Therefore, the medial root of the median nerve in the strict sense was absent, and the median nerve arose from the common trunk with the ulnar nerve. In the plexus on the right side, a long aberrant branch was found, which arose as an extra anterior divison of the middle trunk and joined peripherally the medial cord at a point where the cord formed the common trunk with the lateral root of the median nerve.These findings were compared with previous data obtained from other primates.     

The source of the nerve fibres forming the deep muscular and circular muscle plexuses in the small intestine of the guinea-pig

Summary A quantitative ultrastructural study was made of the neuntes forming the deep muscular and circular muscle plexuses of the guinea-pig small intestine following microsurgical lesions designed to interrupt intrinsic and extrinsic nerve pathways within the intestinal wall. Removal of a collar of longitudinal muscle with attached myenteric plexus from the circumference of a segment of small intestine resulted in the subsequent disappearance of 99.3% of neurites in the underlying circular muscle. The few surviving neurites in the deep muscular plexus and circular muscle disappeared completely from lesioned segments that were, in addition, extrinsically denervated surgically. These results indicate that the majority of nerve fibres in the deep muscular and circular muscle plexuses of the guinea-pig small intestine is intrinsic to the intestine and originates from nerve cell bodies located in the overlying myenteric plexus. At the light-microscopic level, nerve bundles were traced from the myenteric plexus to the circular muscle.     

TRANSPORT OF NORADRENALINE IN SYMPATHETIC NERVES AND THE EFFECT OF NERVE IMPULSES ON ITS CONTRIBUTION TO TRANSMITTER STORES

Abstract— —A study has been made of the contribution of noradrenaline transport along sympathetic nerves to their terminal stores of transmitter by ligating the splenic nerves of the cat, and measuring both the noradrenaline that accumulates above the constriction, and the noradrenaline content of the spleen. The biochemical estimations were supplemented by fluorescence histochemistry. The effect of abolishing efferent impulses in the splenic nerves was examined by cutting their preganglionic nerve supply.
The proximo-distal flow rate for noradrenaline was calculated as 1.4-3.3 mm/hr assuming that all the noradrenaline that accumulates is derived from the cell bodies in the ganglion without net addition or loss in the axons. The process was not dependent on impulse traffic in the nerves, since decentralization did not significantly effect the accumulation. The amount of noradrenaline arrested by the constriction in 24 hr was only 1 per cent of the stores in the terminals of those nerves, and consequently no change was detected in the spleen's noradrenaline content as a result of constricting its nerve supply.
In the presence of an intact reflex pathway to the spleen, the stress of the operative procedure produced a marked constriction of the spleen, and depletion of its noradrenaline content. These changes could be prevented either by section of the preganglionic splanchnic nerves, or by ligation of the splenic nerves, thereby blocking the conduction of efferent nerve impulses.
The evidence favours a proximo-distal flow of noradrenaline in sympathetic nerves, independent of nerve impulses, which makes, however, a negligible quantitative contribution to the terminal stores of transmitter.     

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     

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.     

Somatostatin in human enteric nerves

Summary Somatostatin-immunoreactive nerves and endocrine cells were localized by use of immunohistochemistry in human stomach, small and large intestine. The nature of the immunoreactivity in acid extracts of separated layers of intestine was determined with separation by high pressure liquid chromatography followed by detection with radioimmunoassay; authentic somatostatin-14 was found in the external musculature, which contains nerves, and in the submucosa and mucosa, which contain both nerve fibres and endocrine cells.The distribution of somatostatin nerves in the gastric antrum, duodenum, jejunum, ileum, ascending and sigmoid colon, and rectum is described. In the intestine many positive perikarya and fine varicose fibres were seen. Mucosal fibres formed a sub-epithelial plexus and a looser network in the lamina propria; this nerve supply was less dense in the large intestine. Submucous ganglia contained positive perikarya and terminals; many terminals formed pericellular baskets, mainly around non-reactive cells. A small number of nerve fibres were associated with submucosal blood vessels. The innervation of the circular and longitudinal muscle was sparse. Positive nerve terminals were seen in the myenteric plexus, although fewer than in the submucous ganglia; positive perikarya were scarce in myenteric ganglia. Somatostatin-immunoreactive nerves were found in the muscle layers and myenteric plexus of the gastric antrum, but were not detected in the antral mucosa and all layers of the gastric body.The distribution of human enteric somatostatin nerves is compared to that in small laboratory animals, and possible roles for these nerves are discussed.     

Selective uptake of noradrenaline,dopa, and 5-Hydroxytryptamine by the nervous system of Phocanema decipiens (Nematoda): A light autoradiographic and ultrastructural study

As determined by light microscopic autoradiography, parts of the nervous system of Phocanema decipiens have selective and high affinity mechanisms for the uptake of tritiated noradrenaline, dihydroxyphenylalanine (dopa) and 5-hydroxytryptamine. In the nervous system, noradrenaline is accumulated only by the four papillary nerves and two fibers in the nerve ring. The precursor dopa is also taken up by these neurons and, in addition, by the lateral nerves. 5-Hydroxytryptamine is accumulated by the three pharyngeal nerves, two cells in each lateral ganglion, and two other fibers in the nerve ring. With adjacent ultrathin sections, the labelled papillary nerve and lateral ganglion were examined ultrastructurally and found to contain various dense core vesicles which are similar to those in other aminergic neurons. The adjoining unlabelled cells of the same neurons are found, on the other hand, to contain dense agranular vesicles. With these results, the noradrenaline accumulating neurons are suggested to be noradrenergic and to contain the amine synthesizing enzymes. The lateral nerves are regarded, for the present, as dopaminergic neurons. These suggestions are in agreement with the previous demonstration of catecholaminergic neurons in this nematode. The 5-hydroxytryptamine accumulating neurons are tentatively identified as tryptaminergic.     

NEUROCHEMICAL PROPERTIES OF ADRENERGIC NERVES REGENERATED AFTER 6-HYDROXYDOPAMINE

Abstract— The uptake-storage properties and synthesis of noradrenaline, and fluorescence morphology of adrenergic nerves which have been allowed to regenerate for 4 weeks after a chemical sympathectomy produced by 6-hydroxydopamine have been investigated in mouse iris and atrium. The regenerated nerve terminals displayed a lower formaldehyde-induced fluorescence intensity whereas the non-terminal axons exhibited a stronger fluorescence intensity and a more beaded appearance compared with mature nerves. The endogenous noradrenaline concentration after 6-hydroxydopamine was 30% in iris and 45% in atrium compared to control values. Recovery of [³H]noradrenaline uptake was found to be more rapid than that of endogenous noradrenaline concentration after the 6-hydroxydopamine treatment. [³H]Noradrenaline uptake in regenerating and adult mature nerves both obeyed Michaelis-Menten kinetics having identical K_m values. There was a close correlation between [³H]noradrenaline uptake and nerve density of adrenergic nerves regenerated after 6-hydroxydopamine. These results show that [³H]noradrenaline uptake is a better index for the number of regenerated nerve terminals than is the endogenous noradrenaline concentration. The retention of [³H]noradrenaline taken up and accumulated in vitro was about the same in regenerated and mature nerves, although a slight tendency to less effective retention was observed in the regenerated nerves. Subcellular distribution studies showed that relatively less [³H]noradrenaline was recovered in the microsomal fraction after 6-hydroxydopamine treatment. The formation of ¹⁴C-labelled catecholamines from [¹⁴C]DOPA was higher in regenerating nerves than indicated by the endogenous noradrenaline concentration but lower than that indicated by the [³H]noradrenaline. It is concluded that the regenerating nerves contain less endogenous noradrenaline than adult mature nerves and that the uptake mechanism develops promptly, whereas the development of the storage mechanism lags behind.     

Distribution of intrinsic nerve cell bodies and axons which take up aromatic amines and their precursors in the small intestine of the guinea-pig

Summary The sites of uptake, decarboxylation and retention of 1-dopa and the uptake and retention of dopamine and 6-hydroxytryptamine in the small intestine of the guinea-pig have been localised histochemically with a fluorescence technique for arylethylamines. In segments of ileum from untreated guinea-pigs only noradrenergic axons are fluorescent; these axons were eliminated by surgical denervation (crushing nerves running to the intestine through the mesentery) or by chemical denervation with 6-hydroxydopamine. In denervated segments of ileum, cell bodies and processes of intrinsic neurons become fluorescent after the injection of 1-dopa, dopamine or 6-hydroxytryptamine and the inhibition of monoamine oxidase, as do cells of Brunner's glands and Paneth cells. About 11% of the nerve cell bodies in the submucous plexus and 0.4% of those in the myenteric plexus become fluorescent. Varicose intrinsic axons which take up amines are found amongst the nerve cell bodies of the myenteric and submucous plexuses. They also ramify in the principal connections of the plexuses, in the tertiary strands of the myenteric plexus, in the deep muscular plexus and contribute sparse supplies of axons to arterioles in the submucosa and to the lamina propria of the mucosa. The axons are resistant to the degenerative actions of 6-hydroxydopamine.It is suggested that the intrinsic amine handling axons are more likely to utilise an indolamine related to 5-hydroxytryptamine than they are to utilise a catecholamine as a neurotransmitter.     

An anomalous muscle (accessory subscapularis-teres-latissimus muscle) in the axilla penetrating the brachial plexus in man.

An anomalous muscle passing through the brachial plexus was found in 10 cases out of 380 sides of 190 human cadavers in the dissection course. The muscle was designated as 'accessory subscapularis-teres-latissimus muscle'. This muscle arose near the lateral margin of the scapula, either from the surface of the subscapularis muscle or from the border of the quadrangular terminal tendon of the latissimus dorsi or from both of those sources when the muscle was divided into two heads. It ran obliquely upward to fuse with the insertion of the subscapularis. The largest anomaly was 2.5 cm in width and 7 cm in length. This muscle could be classified into three types on the basis of its nerve supply and its relation to the brachial plexus. The type I muscle crossed over the axillary and lower subscapular nerves, behind the radial nerve and was innervated by the lower subscapular nerves. The type II musclepenetrated the brachial plexus separating the radial nerve into two roots; the upper from the posterior division of the upper trunk and the lower from the posterior divisions of the middle and lower trunks. The type II muscle was supplied by a branch of the radial nerve, which originated always at the same level as the origin of the thoracodorsal nerve. The type III muscle passed through the further more ventrocaudal level of the plexus; in one case it divided the radial nerve into an upper root from the posterior divisions of the upper and middle trunks and a lower root from the lower trunk, and, in another case, into an upper main root from all the three trunks and a lower slender root from the lower trunk. The type III muscle was supplied by branches from the radial and in addition from the thoracodorsal nerve in one case. In four out of ten cases, the subscapular or thoracodorsal artery also passed posterior to the anomalous muscle. A discussion was made on the nature of the anomalous muscle.     

Monoaminergic nerves in the skin of plaice Pleuronectes platessa (L.)

1. The fluorescent histochemical technique of Falck and Hillarp was applied to plaice skin. The presence of monoaminergic nerve terminals, containing predominantly stores of adrenaline, forming a plexus in and around the melanophore layer was demonstrated. 2. Such stores were enriched by noradrenaline in the presence of monoamine oxidase inhibitor, unaffected by spinal section, depleted by spinal nerve section or ligatures and abolished by reserpine. 3. The observations support the view that teleost sympathetic melanophore aggregating nerves are truly adrenergic.