Somatostatin-like immunoreactivity in rat thyroid

Summary Somatostatin-like immunoreactive cells of the rat thyroid gland at various ages were investigated immunohistochemically. The number of cells per lobe in 5 m sections increased with age. Immunopositive cells were evident as small clusters in the older age group (8 to 24 months old) but not clustered in the younger age group (3 to 5 months old). This type of proliferation was termed S-cell hyperplasia in a manner similar to C-cell hyperplasia observed in the aged rat thyroid.     

Somatostatin-like immunoreactivity in human sympathetic ganglia

Summary The localization of somatostatin-like immunore-activity (SOM-LI) was examined in human lumbar sympathetic ganglia using the peroxidase-antiperoxidase method. Few of the principal neurons showed immunolabelling for somatostatin and sparse networks of nerve terminals were unevenly associated with ganglion cells. Using light microscopy, the most intense SOM-LI was seen in the perinuclear zone of the neurons. Electron-microscopically, the staining was localized on the membranes of the Golgi apparatuses. In the nerve terminals, SOM-LI was seen inside the small vesicles (40–60 nm diameter). All neurons with SOM-LI were also found to be tyrosine-hydroxylase immunoreactive when excamined with a double-staining technique. These results provide evidence that somatostatin and noradrenaline co-exist in human sympathetic neurons.     

Plasma Somatostatin-like immunoreactivity in chemically sympathectomized dogs

The present study was designed to determine the role of the adrenergic nerves upon basal and postprandial gastric and pancreatic SLI release. In 19 chemically sympathectomized dogs peripheral venous plasma SLI levels in the basal and postprandial state were significantly below those of 30 controls for the first 135 min after the ingestion of a fat-protein meal. To determine the origin of this reduction, the SLI release from fundus, antrum and pancreas was studied in anesthetized dogs during the gastric phase of a meal at either pH 7 or pH 2. In response to a liver meal at pH 7 fundic, antral and pancreatic vein SLI levels were below the control and the rise in inferior vena cava SLI was abolished. In response to a liver meat at pH 2, the rise in antral and pancreatic vein SLI as clearly reduced in the sympathectomized dogs, while the decrease in fundic SLI was not influenced. The data demonstrate that adrenergic innervation plays a role in basal and postprandial SLI release from the stomach and pancreas.     

Somatostatin-like immunoreactivity in non-pyramidal neurons of the human entorhinal region

Summary The distribution of somatostatin-immunoreactive cells and processes throughout the human entorhinal region and subjacent white matter was examined either by the unlabelled antibody-enzyme method or by the avidin-biotin method. The brain slices were obtained at autopsy with a short post-mortem delay. The majority of somatostatin immunoreactive nerve cells was found in the inner principal layer and subjacent white matter. In addition, individually scattered immunoreactive neurons were observed in both the outer principal layer and lamina dissecans. The immunoreactive perikarya varied in shape and ranged in size from 10 to 30 m. Without exception the neurons could be classified as belonging to the group of non-pyramidal neurons. Each neuron gave rise to a few thick dendrites and a thin axon with a beaded appearance. In the adult human brain, the pattern formed by lipofuscin granules deposited in the nerve cells can be considered characteristic for the type of the neuron. Therefore, immunoreactive perikarya were documented, destained of chromogen and restained to demonstrate lipofuscin pigment and basophilic substance. It became evident from these studies that the previously immunoreactive cells were characterized by a large rounded and eccentrically located nucleus, sparse basophilic substance and, in most cases, a lack of lipofuscin granules. A few of the immunoreactive cells were laden with coarse pigment granules. The findings permit classification of entorhinal somatostatin-immunoreactive neurons as either non-pigmented or pigment-laden non-pyramidal neurons.Dedicated to Prof. Dr. J. Lang, Würzburg, on the occasion of his 65th birthdayA portion of the results has been presented at the annual meeting of the European Neuroscience Association 1986 in Marseille, France (Friederich-Ecsy et al. 1986)     

Somatostatin-like immunoreactivity in the retinae of adult and embryonic chickens

Somatostatin, a tetradecapeptide that inhibits growth hormone release, has a widespread distribution in the central and peripheral nervous systems and other cell types. In the present investigation, the chicken neural retina was studied for the presence of structures exhibiting somatostatin-like immunoreactivity by utilizing an indirect immunofluorescence technique. Controls for specificity of staining were performed on alternate sections. Several types of distinctly labeled neurons and their processes were evident in sections of adult and late embryonic retinae. Cresyl violet staining showed that these neurons, which were scattered peripherally and more numerous centrally, occupied several strata within the inner nuclear, inner plexiform, and ganglion cell layers. Labeled neurites of immunoreactive perikarya coursed within these layers as well, often approaching other immunoreactive cells and fibers. The morphology and position of the somatostatin-containing neurons indicated that these neurons were amacrine, horizontal, or ganglion associational cells. These findings indicate that somatostatin is first detectable in the retina during the late embryonic stages of the chicken.     

Leu-enkephalin immunoreactivity in the pig pineal gland

Leu-enkephalin-positive structures in the pig pineal gland were demonstrated immunohistochemically using mouse monoclonal antibody. The pineal glands were obtained from the newborn, 21-day and 7-month old female pig. The immunopositive nerve fibers were observed in the pineal gland as well as in the epithalamic areas. The leu-enkephalin-immunoreactive nerve fibers (single or forming small bundles) were localized mainly in the proximal part of the pineal and they were scarce in other parts. The localization of the fibers points to a central source of this innervation. The study did not show any age-dependent differences in the distribution and density of leu-ekephalin-positive nerve fibers.     

Somatostatin-like immunoreactivity in pancreatic extracts of a sahelian lizard (Varanus exanthematicus) during starvation

In the Varanus exanthematicus, the pancreatic complex comprises the true pancreas as well as an intrasplenic islet comparable to a Brockmann's body. Somatostatin content and concentration were estimated by radioimmunoassay in acetic acid extracts of both organs. Relatively large amounts of somatostatin (SLI) are present in the pancreas (2.17 +/- 0.07 micrograms) without any difference in distribution between the cranial (CP) and mediocaudal (MCP) regions. The intrasplenic islet contains as much SLI material as the whole pancreas (3.38 +/- 0.85 microgram); thus, this primitive organ presents a very high hormonal concentration (109.34 +/- 40.30 ng/mg wt). Serial dilutions of the extracts gave parallel immunoassay displacement curves and gel-filtration revealed two immunoreactive peaks: the most important one was found in the synthetic tetradecapeptide fraction, the other one near the void volume fraction. These results show an immunological similarity between the SLI substance of the pancreatic complex and the synthetic somatostatin; however, a molecular heterogeneity must not be excluded. The results are discussed from a phylogenetic point of view.     

Distribution of synaptophysin immunoreactivity in guinea pig heart

The distribution of synaptophysin, an integral polypeptide of presynaptic vesicle membranes, was investigated in guinea pig heart by immunohistochemistry using monoclonal antibodies. Synaptophysin immunoreactivity was found in varicose nerve terminals in all regions of the heart. Dense networks of immunoreactive varicosities were found to surround the vasculature and to be located within the subendocardial layers of the atria and ventricles, the highest levels being seen in the innervation of the conductive system. As synaptophysin is probably a component of the presynaptic vesicles of all synapses, its use as a marker of all nerve terminals within the heart is proposed.     

Distribution of synaptophysin immunoreactivity in guinea pig heart

Summary The distribution of synaptophysin, an integral polypeptide of presynaptic vesicle membranes, was investigated in guinea pig heart by immunohistochemistry using monoclonal antibodies. Synaptophysin immunoreactivity was found in varicose nerve terminals in all regions of the heart. Dense networks of immunoreactive varicosities were found to surround the vasculature and to be located within the subendocardial layers of the atria and ventricles, the highest levels being seen in the innervation of the conductive system. As synaptophysin is probably a component of the presynaptic vesicles of all synapses, its use as a marker of all nerve terminals within the heart is proposed.Supported by the Deutsche Forschungsgemeinschaft (SFB 90) requests should be sent     

Neurotensin immunoreactivity in the central nucleus of the rat amygdala: an ultrastructural approach

Neurotensin (NT) was demonstrated in the central nucleus of the rat amygdala (CNA) using a modification of the avidin-biotin complex immunohistochemical technique. Electron-dense reaction product (particles were 15-25 nm in diameter) was localized in perikarya, dendrites, axons, and axon terminals. It was found also associated with profiles of rough endoplasmic reticulum, mitochondria, microtubules, and small agranular as well as large granular vesicles. In distal dendrites, the reaction product was associated with microtubules, vesicles, and postsynaptic densities. Axon terminals of three types formed synaptic contracts with NT-immunoreactive neurons in the CNA: one was characterized by numerous round or oval agranular vesicles, the second by numerous pleomorphic vesicles, and the third by agranular vesicles that were loosely distributed and pleomorphic. All three types formed symmetric axosomatic and asymmetric axodendritic contacts. NT-immunoreactive axon terminals containing small round agranular vesicles stood out clearly from the intermingling profiles of immunonegative structures. We found numerous glomeruli, each consisting of a central NT-immunoreactive dendrite surrounded by all three types of axon terminals. We observed that some NT-immunoreactive terminals formed symmetric axoaxonal contacts with each other, providing evidence for the presence of local NT-to-NT circuits, whereas many others synapsed with axon terminals devoid of NT immunoreactivity.     

The distribution of galanin message-associated peptide-like immunoreactivity in the pig.

Using a radioimmunoassay (RIA) developed to the N-terminal part of the predicted sequence of porcine galanin message-associated peptide (GMAP), we have confirmed the existence of GMAP-like immunoreactivity (-LI) in normal porcine tissues. GMAP-LI was found to parallel the distribution of galanin-immunoreactivity (-IR), although consistently the concentrations detected were, on a molar ratio, significantly less than those measured for galanin throughout the gastrointestinal tract, brain, spinal cord, adrenal and pituitary gland. As cleavage of the prohormone would be expected to produce galanin and GMAP on an equimolar basis, it is possible that the endogenous, intact GMAP peptide does not fully cross-react with the antibody raised to the N-terminal GMAP sequence. Gel chromatography of tissue extracts revealed a single molecular form of galanin-IR in the gut and four distinct molecular forms in the adrenal gland. GMAP-LI eluted as a single immunoreactive component in the gut, and in the adrenal gland there were two major molecular forms, one of which was apparently also detected by the galanin assay, and a small amount of N-terminal fragment. This molecular heterogeneity seems likely to be a result of the various possible prohormone cleavage products and/or posttranslational processing modifications. Further analysis of the galanin gene products needs to be undertaken in order to confirm this.     

Vasoactive intestinal polypeptide immunoreactivity in the spinal cord of the guinea pig

Summary The distribution of vasoactive intestinal polypeptide-immunoreactive (VIP-IR) neurons in the lower medulla oblongata and the spinal cord has been analyzed in guinea pigs. This study includes results obtained by colchicine treatment and transection experiments. In the spinal cord, numerous VIP-IR varicosities were observed in the substantia gelatinosa of the columna dorsalis; some were also found in the substantia intermedia and the columna anterior. The spinal VIP-IR nerve fibers were mainly of intraspinal origin and oriented segmentally. VIP-IR nuclei in the spinal cord extended dorsally into corresponding regions of the caudal medulla oblongata, namely from the substantia intermedia medialis and lateralis into the vagus-solitarius complex and from the nucleus spinalis lateralis into the area of the nucleus reticularis lateralis. Additional VIP-IR perikarya were observed in the pars caudalis of the nucleus spinalis nervi trigemini. The VIP-IR nuclei within the caudal medulla oblongata probably form a continuous system with those localized within the spinal cord. They may be involved functionally in the modulation of cardiovascular and respiratory regulation in the guinea pig.Supported by the DFG, Carvas SFB 90     

Distribution of acetylcholinesterase and monoamine oxidase in the amygdala of the guinea pig

Summary A study of the amygdala of the guinea pig was carried out on material stained by the Nissl, acetylcholinesterase (AChE) and monoamine oxidase (MAO) methods. The material stained for Nissl substance was used primarily as a reference in determining the distribution of the two enzymes. Regional differences in cell size and/or distribution were noted within the lateral, basal, medial and cortical nuclei. In the AChE preparations, it was observed that the large-celled part of the basal nucleus stained very intensely, the small-celled part of the basal nucleus and ventromedial part of the lateral nucleus more moderately, and the dorsolateral part of the lateral nucleus and cortical nucleus lightly. The central and medial nuclei showed almost no reaction. With the MAO method, the greatest staining reaction was seen in the medial nucleus, the medial part of the cortical nucleus, the anterior amygdaloid area and the ventromedial wedge of the putamen adjacent to the central nucleus. In addition, fibres of the stria terminalis stained very darkly.These findings are discussed in relation to the observations of previous authors employing the same methods.Supported in part by the Canadian Medical Research Council Grant No. M.T. 870 and U.S. Public Health Service Grant No. NS-07998. This aid is gratefully acknowledged. We are indebted to Dr. Gorm Danscher for additional material and to Mr. A. Meier, Mrs. L. Munkøe, Mrs. K. Sørensen, Miss M. Sørensen, Miss D. Valgaard, and Miss B. Ørum for skillful assistance.     

Somatostatin-like immunoreactivity (SLI) in pancreatic and intestinal tissues of the duck. A possible origin for the portal circulating SLI

Substances with Somatostatin-Like Immunoreactivity (SLI) were extracted using 2 N acetic acid, from the three pancreatic lobes and the intestine of the duck. The concentration of SLI was found to be very high in the pancreas (4.2 micrograms/g wet weight), the splenic lobe containing 80% of pancreatic SLI compared with 10% for the dorsal and 10% for the ventral lobes. SLI was equally distributed between duodenum, jejunum and ileum and between their mucosal and muscular layers. Chromatography of pancreatic extracts, using a Sephadex G-25 column, showed mainly the tetradecapeptide form (somatostatin-14, S-14) with a small amount of big somatostatin. Chromatography of intestinal extracts revealed three peaks with SLI: big somatostatin, somatostatin-28 (S-28) and S-14. The substance represented by the predominant peak was co-eluted with that of synthetic S-28. In normal ducks, portal plasma SLI corresponded to big somatostatin S-28 and S-14. After total pancreatectomy the S-14 form disappeared from portal plasma, whereas, when the intestinal blood vessels were ligatured, the S-28 form disappeared. We therefore hypothesize that in portal blood, S-14 has a mainly pancreatic origin, and S-28 a mainly intestinal origin.     

GABA immunoreactivity of calyceal nerve endings in the vestibular system of the guinea pig

Summary Neurotransmitters involved in the vestibular system are largely uncharacterized. On the basis of results of earlier electrophysiological and immunohistochemical experiments, glutamate and gamma-amino-butyric acid (GABA) have been proposed in both mammalian and non-mammalian species as afferent transmitters between the sensory cell and the afferent dendrite. GABA is also suspected to act as an efferent neurotransmitter in the cochlea. We describe in this study the immunocytochemical localization of GABA within the vestibular end organs in the guinea pig. GABA immunoreactivity was found in the calyceal nerve endings surrounding type I hair cells of the vestibular epithelia. The most significant labelings were obtained in the crista ampullaris. Labeling was more difficult to observe in the utricular and saccular macula. These results contribute to the recent proposal that the calyx has a secretory function, and suggest that GABA may have a modulatory influence upon the type I hair cells.     

Neuropeptide Y-like immunoreactivity in intramural ganglia of the newborn guinea pig urinary bladder

Immunoreactive neuropeptide Y (NPY) was demonstrated in neuronal elements in the urinary bladder wall of the newborn guinea pig. Numerous intramural ganglia were found lying among the smooth muscle bundles and in the submucosa, and NPY-like immunoreactive nerve cell bodies were demonstrated within all of these ganglia. Nerve fibres containing NPY were also richly distributed in the detrusor muscle, submucosa and around blood vessels. In dissociated cell cultures from newborn guinea pig detrusor muscle, a subpopulation (70-85%) of both mononucleate and binucleate intramural neurones was shown to contain NPY-like immunoreactivity. A low percentage (1-6%) of the intramural bladder neurones contained dopamine-beta-hydroxylase. In conclusion, while some NPY-containing nerve fibres in the wall of the bladder are of sympathetic origin, especially those supplying blood vessels, the results of this present study establish that many of these NPY-containing nerve fibres originate from non-adrenergic cell bodies within the intramural bladder ganglia.