Origin of galanin in nerves of cat airways and colocalization with vasoactive intestinal peptide

Galanin is a 29 amino acid residue neuropeptide. In mammalian airways, galanin is found in nerve fibers associated with airway smooth muscle, bronchial glands, and blood vessels, and in nerve cell bodies of airway ganglia. The present study was conducted to determine if galanin-containing fibers in the walls of feline airways originate from the nerve cell bodies of airway ganglia. The colocalization of galanin with vasoactive intestinal peptide was also investigated. Organotypic cultures of cat airways were held in culture for 0 (nonculture control), 3, 5, and 7 days. After each culture period, the distribution of galanin and the colocalization of galanin with vasoactive intestinal peptide were determined by immunocytochemistry. Galanin-containing fibers were found in bronchial smooth muscle, around bronchial glands and in the walls of bronchial arteries and arterioles throughout the culture period. Nerve fibers and cell bodies containing both galanin and vasoactive intestinal peptide were observed after all culture periods. Nerve fibers and cells bodies that contained galanin frequently contained vasoactive intestinal peptide as well, but nerve fibers with only galanin or vasoactive intestinal were also observed. Galanin- and vasoactive intestinal peptide-containing nerve fibers and cell bodies were both well maintained throughout the culture period. The findings show that galanin-containing nerve fibers associated with bronchial smooth muscle, bronchial glands, and bronchial arteries, originate from nerve cell bodies of intrinsic airway ganglia, and that galanin and vasoactive intestinal peptide are frequently colocalized in these neurons.     

Nitric oxide synthase-containing nerve fibers and neurons in the genital tract of the female mouse

Nitric oxide (NO) is generated intracellularly from L-arginine by the action of the enzyme nitric oxide synthase (NOS). The present investigation demonstrates immunoreactivity against NOS and nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase activity in nerve cells and fibers of the reproductive system of the female mouse. The density of nerve fibers staining for NOS varied among different genital organs. The ovary and Fallopian tube were devoid of NOS-positive nerves. The uterine horns received sparse innervation by NOS-containing nerve fibers. The most abundant NOergic innervation was found in the uterine cervix and vagina, where the nerve fibers ran parallel to the smooth muscle bundles and beneath the epithelium; they also accompanied intramural blood vessels. The vaginal muscular wall contained single or groups of NOS-reactive nerve cells. Clusters of NOS-containing neurons were located in Frankenhäuser's ganglion at the cervico-vaginal junction. NO may therefore act as a transmitter in the nervous control of the female reproductive tract.     

Ultrastructural identification of non-adrenergic,non-cholinergic nerves in the rat anococcygeus muscle

The innervation of the rat anococcygeus muscle has been investigated ultrastructurally following fixation with a modified chromaffin reaction for the demonstration of biogenic amines (Tranzer and Richards, 1976). Three types of nerve profiles were revealed: (1) 60-70% of the profiles are adrenergic; (2) less than 5% of the profiles appear to be cholinergic; (3) up to 40% of the profiles are distinguished by the presence of a characteristically high proportion of electron-opaque, chromaffin-negative vesicles, 85-110 nm in diameter. This third type of profile was not affected by 6-OHDA, and is considered to represent the non-adrenergic, non-cholinergic inhibitory innervation of this tissue. Because of the morphological similarity of this nerve type, apart from the smaller vesicle size, to classical peptidergic nerve endings, they have been termed "small p-type" (sp-type). These results are discussed in relation to a previous report describing only two types of nerve profiles in this tissue (Gillespie and Lüllmann-Rauch, 1974).     

Morphology of enkephalin-immunoreactive myenteric neurons in the human gut

The aim of this study was the morphological and further chemical characterisation of neurons immunoreactive for leu-enkephalin (leuENK). Ten wholemounts of small and large intestinal segments from nine patients were immunohistochemically triple-stained for leuENK/neurofilament 200 (NF)/substance P (SP). Based on their simultaneous NF-reactivity and 3D reconstruction of single NF-reactive cells, 97.5% of leuENK-positive neurons displayed the appearance of stubby neurons: small somata; short, stubby dendrites and one axon. Of these leuENK-reactive stubby neurons, 91.3% did not display co-reactivity for SP whereas 8.7% were SP-co-reactive. As to their axonal projection pattern, 50.4% of the recorded leuENK stubby neurons had axons running orally whereas in 29.4% they ran anally; the directions of the remaining 20.2% could not be determined. No axons were seen to enter into secondary strands of the myenteric plexus. Somal area measurements revealed clearly smaller somata of leuENK-reactive stubby neurons (between 259±47 m² and 487±113 m²) than those of putative sensory type II neurons (between 700±217 m² and 1,164±396 m²). The ratio dendritic field area per somal area of leuENK-reactive stubby neurons was between 2.0 and 2.8 reflecting their short dendrites. Additionally, we estimated the proportion of leuENK-positive neurons in comparison to the putative whole myenteric neuron population in four leuENK/anti-Hu doublestained wholemounts. This proportion ranged between 5.9% and 8.3%. We suggest leuENK-reactive stubby neurons to be muscle motor neurons and/or ascending interneurons. Furthermore, we explain why we do not use the term Dogiel type I neurons for this population.     

鸡输卵管蛋白分泌部前后段的神经支配差异

将ＣＢ－ＨＲＰ分别注入母鸡输卵管蛋白分泌部的前半段和后半段,以研究其神经分布的差异,结果表明,支配前半段与后半段的神经元分布位置和数目均有一定差异。后半段接受来自胸２至腰荐１３（Ｔ２－ＬＳ１３）脊神经节的感觉神经,Ｔ１－ＬＳ１３交感于神经节、内脏神经节和肾上腺神经节的交感神经,盆神经节的副交感神经以及肠神经节的神经。前半段的感觉和交感神经的来源与后半段的基本相同,但前半段的副交感神经主要来自迷走神     

Quantitative electron microscopic studies on the innervation of the human thymus

Summary Quantitative electron microscopic studies have been carried out on the human thymus. According to the equation L _v =(2n)/F (Hennig, 1963) we have calculated that there is less than 0.204 mm nerve per 1 mm³ thymus tissue inside the blood-thymus-barrier (level of significance of 0.95). This result is compared to the degree of innervation in brown adipose tissue, which contains more than 160 mm nerve per 1 mm³ tissue. The biological significance of the paucity of neuronal elements in the thymus is undetermined.We are much obliged to Dipl. Ing. Dr. A. Hennig for his advice in the mathematical evaluation of our results.We are also indebted to Dr. med. A. Krug (Chir. Universitätsklinik Kiel) for human thymus material.This investigation was supported by the Deutsche Forschungsgemeinschaft.     

Composition of the medial and posterior articular nerves of the mouse knee joint

The number and the distribution of fiber size in the medial (MAN) and posterior (PAN) articular nerves of the mouse knee joint were studied by electron microscopy. The MAN contained 75 &#45 28 nerve fibers consisting of 63 &#45 24 unmyelinated and 12 &#45 6 myelinated fibers. The PAN was composed of 195 &#45 50 nerve fibers, namely 129 &#45 28 unmyelinated and 66 &#45 24 myelinated fibers. A skewed unimodal distribution of the unmyelinated nerve fiber diameters was seen in both nerves ranging from 0.1 to 1.2 &#119 m with a maximum between 0.3 and 0.6 &#119 m. The myelinated nerve fibers in the MAN ranged from 1 to 8 &#119 m with a peak between 2 and 5 &#119 m. In the PAN, their diameters ranged from 1 to 12 &#119 m with a clearly visible peak at 4-5 &#119 m and a plateau at 8-9 &#119 m that may represent a second maximum. These data show that the knee joint innervation of the mouse is comparable to those of the cat and rat concerning the types of nerve fibers and the composition of the two nerves. However, in relation to the much smaller area of tissue to be innervated the total number of primary afferents is considerable smaller in the mouse.     

Ultrastructural patterns of human dentinal tubules, odontoblasts processes and nerve fibres

The structure of the dentin, consists of the following elements: the odontoblastic processes, dentinal tubules and their periodontoblastic spaces. The odontoblasts are aligned in a single layer in the periphery of the dental pulp and secrete the organic components of dentin. The vitality of dentin is mediated too by the nerve fibres. The ultrastructure of the trigeminal sensory nerves in dentin, especially in relation to odontoblasts remains to be clarified. We studied the third molars and young premolars. The specimens were fixed in glutaraldehyde immediately after extraction. Our investigations give evidence to prove that the distribution of the dentinary tubules is homogeneous, containing a principal odontoblastic prolongation in the regions of the inner dentine, and only in special cases more than one. The area of the dentinary tubules and the odontoblastic prolongations' area were studied. The nervous fibres appeared accompanying 30-70% of the odontoblastic prolongations and their synapsis-like relation with the odontotoblastic processes was demonstrated. The existence of very few periodontoblastic spaces, and intradentinal sensory axons, as well as the intercellular connections will allow us to discover more about the mechanisms of the dentinary permeability, and its significance in maintenance and repair of the human pulpodentinal complex.     

Calcitonin gene-related peptide expression at endplates of different fibre types in muscles in rat hind limbs

Calcitonin gene-related peptide (CGRP) occurs only in some motoneurons. In this study, the presence of CGRP in motor endplates in relation to muscle fibre types was examined in slow (soleus muscle) and fast [tibialis anterior (TA) and extensor digitorum longus (EDL)] leg muscles of the rat. CGRP was detected by use of immunohistochemical methods, and staining for the mitochondrial-bound enzyme NADH-TR was used for demonstration of fibre types. The fibres showing low NADH-TR activity were interpreted as representing IIB fibres. All such fibres located in the superficial portion of TA were innervated by endplates displaying CGRP-like immunoreactivity (LI), whereas in the deep portion of TA some of these fibres lacked CGRP-LI at their endplates. Thirty per cent of the IIB fibres in EDL showed CGRP-LI at the endplates. All fibres in TA and EDL displaying high NADH-TR activity and interpreted as type-IIA fibres, lacked CGRP-LI in their motor innervation. One third of the fibres with intermediate NADH-TR activity in TA exhibited CGRP-LI at their endplates, whereas in EDL only few such fibres displayed CGRP-LI in the endplate formation. These fibres are likely to belong to type-IIX or type-I motor units. CGRP-LI was very rarely detected at the endplates in the soleus muscle. These observations show that distinct differences exist between the slow muscle, soleus, and the fast muscles, TA and EDL, but that there are also differences between the different types of fibres in TA and EDL with respect to presence of CGRP-LI at the endplates. As CGRP-LI was frequently detected at endplates of IIB fibres, it is likely that CGRP has a particular role related to the differentiation and maintenance of these fibres.