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R Elde

Publications and source records attributed to R Elde.

At least 109 records · Page 6Linked to original sources

Possible role of somatostatin in the regulation of the sexually differentiated steroid metabolism and prolactin receptor in rat liver.

The regulation of the sexually differentiated metabolism of 4-[4-14C]androstene-3,17-dione and the presence of PRL receptors in rat liver were studied. Electrolytic lesions in male rats placed in a restricted area in the anterior hypothalamic periventricular area caused a feminization of hepatic steroid metabolism (i.e. increased the 5 alpha-reductase and decreased the 6 beta- and 16 alpha-hydroxylase activities) and of the levels of PRL receptors (increased binding of [125I]-labeled human PRL). After periventricular lesions, histochemical analysis revealed a decrease in somatostatin-like immunoreactive cell bodies in the periventricular area. Also the number of immunoreactive somatostatin fibers in the median eminence was dramatically reduced. Somatostatin levels in the median eminence, as measured by RIA, were reduced to approximately 2-10% of control values after periventricular lesions. Large lesions in the amygdaloid complex in male rats caused a partial feminization of hepatic steroid metabolism and PRL receptors. Passive immunization during 4 days by multiple injections of an antiserum generated against somatostatin resulted in a partial feminization of the male rat liver. When somatostatin was injected into female rats, the PRL receptors were reduced to approximately 60% of the control female receptor levels. The present study indicates that the anterior periventricular hypothalamic area is important in the control of the sexually differentiated steroid metabolism and PRL receptors in the liver and that the amygdaloid complex also may have regulatory influences on this system. A possible central neuro-endocrine mediator of these sex differences in the liver could be somatostatin or a related compound.

Androstenedione↗

Corticotropin-releasing factor immunoreactivity is widely distributed within the central nervous system of the rat: an immunohistochemical study.

The discovery of a 41-amino acid peptide with potent corticotropin-releasing factor properties has prompted a search for neurons that contain this substance and potentially utilize it in intercellular communication. The present study utilized immunohistochemical methods and an antiserum directed against a synthetic replica of ovine corticotropin-releasing factor. The rat hypothalamus was found to contain striking immunoreactive groups of neuronal perikarya within the paraventricular, periventricular, and anterior hypothalamic nuclei, some of which are likely to project to the external layer of the median eminence and thereby comprise a hypophysiotropic system. Certain other hypothalamic nuclei, as well as many other regions of the central nervous system, were found to contain corticotropin-releasing factor-immunoreactive neurons. Among the most prominent of these were neurons in the bed nucleus of stria terminalis, the central nucleus of the amygdala, the region of the dorsal raphe, locus ceruleus, the external cuneate nucleus, and the medullary reticular formation. Thus, corticotropin-releasing factor, like many other neurohormones and peptides, may participate in neuroendocrine regulation as well as play a role as a neurotransmitter-like substance in numerous extrahypothalamic circuits.

Animals↗

The distribution of enkephalin immunoreactive neuronal cell bodies in the monkey brain: preliminary observations.

The distribution of enkephalin immunoreactive cell bodies was studied in the central nervous system of colchicine-treated monkeys. They followed a distribution pattern similar to enkephalin immunoreactive nerve fibers and terminal fields, and were found throughout much of the spinal cord and brain. Large numbers of enkephalin immunoreactive cell bodies were seen in the brainstem, hypothalamus and in telencephalic nuclear areas. In most regions, the distribution of enkephalin immunoreactive cell bodies in the monkey brain was similar to that reported for the rat.

Animals↗

A microcomputer-aided system for the graphic reproduction of neurohistochemical maps.

In this report we describe the computer hardware and software used in the production of microscopic maps from histochemical data. The maps may consist of lines, shaded and symbols, each drawn in any of four styles and in any of four colors. The system employs a microscope stage digitizer and plotter to produce an initial map containing precise positional information. A desktop computer equipped with a four-color digital plotter and a digitizing tablet is used to produce the final map. The positional information of the initial map is traced on the computer's digitizer to produce the final map. The software enabling this transformation is specialized for three basic types of structures. Cytoarchitectural landmarks and macroscopic morphology are represented by lines. Areas of a microscopic field which have some degree of visibly definable characteristics such as axonal staining are represented by areas shaded with dots. Microscopic structures of individual interest are represented by various symbols. Other program options allow the computation and printing of figure areas and perimeters while digitizing shaded areas, storage of all map information on a mass-storage medium, the drawing of alignment registration marks, and flexible access to and prompting for all program options. While the role of the anatomist in recognition and discrimination of meaningful histochemical information is unchanged, production of microscopic maps using this system consumes far less time than hand methods and results in uniform, accurate illustration.

Animals↗

Immunohistochemical localization of putative neurotransmitters within the feline nucleus tractus solitarii.

With the aid of immunohistochemical techniques the distribution of substance P, met-enkephalin, serotonin, somatostatin, alpha-melanocyte stimulating hormone, neurotensin and neurophysin immunoreactivities were mapped throughout the rostro-caudal extent of the cat's nucleus tractus solitarii. Three of the putative neurotransmitters (substance P, enkephalin and serotonin) were found to be widely distributed as varicose fibers and punctate structures. The densities of their immunoreactivities were plotted in a range from very dense, dense, moderate, occasional, to none, at different levels of the nucleus of the solitary tract. Substance P immunoreactivity was the most varied and dense of all the neurotransmitters studied. Its accumulations ranged from very dense in the lateral, dense in portions of the parvocellular and lateral, moderate in medial and commissural and occasional in ventrolateral and portions of the parvocellular subdivisions. Both the enkephalin and serotonin immunoreactivities had patterns similar to that of substance P immunoreactivity, although their amounts were not as great. Following colchicine treatment neurons containing substance P and enkephalin immunoreactivity were found in many subdivisions of the nucleus of the solitary tract. Somatostatin, alpha-melanocyte stimulating hormone, neurotensin and neurophysin immunoreactivities were present in the nucleus of the solitary tract as isolated varicose fibers scattered throughout the nucleus. Immunoreactive neurons were not found for these putative neurotransmitters after colchicine treatment. The presence of substance P immunoreactivity within subdivisions which receive visceral afferent input is discussed in relation to the role of substance P as a possible transmitter of the afferent limb of the vagus nerve. The distribution of enkephalin and serotonin immunoreactivities in the nucleus of the solitary tract reflect their involvement in the regulation or modulation of cardiovascular and respiratory functions. While the significance of somatostatin, alpha-melanocyte stimulating hormone, neurotensin and neurophysin immunoreactivities within the nucleus of the solitary tract is not understood at present, these substances might possibly play a role in visceral functions.

Afferent Pathways↗

The distribution of enkephalin immunoreactive fibers and terminals in the monkey central nervous system: an immunohistochemical study.

Using immunohistochemical techniques, the distribution of met-enkephalin fibers and terminals was studied in the central nervous system of adult old-world monkeys. Areas which showed the greatest density of immunoreactivity included substantia gelatinosa, nucleus tractus solitarius, nucleus parabrachialis, substantia nigra, median eminence, globus pallidus (external segment), patches within the striatum and the region of nucleus accumbens and the olfactory area. Striking and discrete zones of enkephalin immunoreactive fibers and terminals which did not conform to known nuclear boundaries were observed in the latter areas. The distribution of enkephalin in the monkey is compared to what has been described in the rat central nervous system. In general, the two species are similar, however, differences were observed in some areas including the hypoglossal nucleus, substantia nigra and in the region of the nucleus accumbens and olfactory area. The results are discussed with regard to the possible functional significance of enkephalin localization in regions related to regulation of pain, mood, and autonomic function.

Animals↗

The differential distribution and relationship of serotoninergic and peptidergic fibers to sympathoadrenal neurons in the intermediolateral cell column of the rat: a combined retrograde axonal transport and immunofluorescence study.

The preganglionic sympathetic neurons in the intermediolateral cell column of the thoracic and upper lumbar segments of the spinal cord which innervate the chromaffin cells in the adrenal medulla, sympathoadrenal preganglionic neurons, were identified by the method of retrograde axonal transport of the fluorescent dyes Fast Blue and True Blue. In rats, Fast Blue or True Blue was injected into the medulla of the left adrenal gland. After a survival period of 5 days, the animals were perfusion fixed, the thoracic and lumbar spinal cord sectioned and processed for the immunofluorescent localization of met-enkephalin, neurophysin, oxytocin, serotonin, somatostatin and substance P immunoreactivity. Neuronal perikarya which were retrogradedly-labeled with Fast Blue or True Blue were observed in the intermediolateral cell column from the T1 to the L2 spinal cord segments. The distribution of the sympathoadrenal neurons was determined by counting the number of retrogradedly-labeled neurons per spinal cord segment. In the five animals used for quantifying the sympathoadrenal preganglionic neurons, the majority (72.3%) of the retrogradely-labeled neurons counted per spinal cord were located within the T7-T12 segments. The T9 segment contained the largest average number (20.1%) of retrogradely-labeled cells in a single segment. Met-enkephalin, serotonin and substance P immunoreactive fibers were prominent in the intermediolateral cell column, whereas oxytocin, neurophysin and somatostatin immunoreactive fibers were sparse. The met-enkephalin, serotonin and substance P fibers were seen surrounding both unlabeled and retrogradely-labeled neurons; somatostatin fibers appeared to preferentially contact retrogradely-labeled neurons; whereas, the neurophysin and oxytocin fibers were not found in proximity to retrogradely-labeled neurons. Met-enkephalin, neurophysin, oxytocin, somatostatin and substance P immunoreactivity were depleted in the intermediolateral cell column below the level of a spinal cord transection. Serotonin immunoreactivity was depleted in the intermediolateral cell column below the level of the transection for five to six segments, but sparse networks of immunoreactive fibers were observed in both the intermediolateral cell column and the ventral horn in more caudal segments. Met-enkephalin, serotonin, somatostatin and substance P immunoreactivity were decreased in both the contralateral and ipsilateral intermediolateral cell column below the level of a spinal cord hemisection, suggesting that both crossed and uncrossed descending pathways exist. Neurophysin and oxytocin immunoreactivity were depleted below the level of the hemisection in the ipsilateral intermediolateral cell column without noticeable decrease in the level of immunoreactivity in the contralateral intermediolateral cell column, suggesting that a decussation does not occur at the level of the spinal cord, but may exist above the level of the hemisection...

Adrenal Medulla↗

Organizational principles in the peripheral sympathetic nervous system: subdivision by coexisting peptides (somatostatin-, avian pancreatic polypeptide-, and vasoactive intestinal polypeptide-like immunoreactive materials).

Sympathetic ganglia and some peripheral tissues of adult guinea pig and cat were analyzed by the indirect immunofluorescence technique with antisera to catecholamine-synthesizing enzymes and some peptides. In the guinea pig, noradrenergic neurons could be subdivided into three populations containing respectively (i) somatostatin-like immunoreactive material, (ii) avian pancreatic polypeptide (APP)-like immunoreactive material, and (iii) apparently only noradrenaline (NA; norepinephrine). A fourth population of sympathetic neurons was nonadrenergic and contained vasoactive intestinal polypeptide (VIP)-immunoreactive material. In the cat many noradrenergic neurons with APP and some without this peptide were seen, but no somatostatin-immunoreactive neurons were observed. Also a population of non-adrenergic, presumably cholinergic, neurons containing a VIP-like peptide was observed. These neuron populations seemed to innervate different tissues with some target specificity. For example, in the nasal mucosa of the cat, nerves containing NA/APP-like immunoreactive material (called NA/APP nerves) were found around small arteries and arterioles, whereas venules and sinusoids were surrounded by nerves containing only NA (called NA nerves). Also in the submandibular salivary gland of the cat, the NA/APP nerves surrounded arteries and arterioles, whereas NA nerves were seen in relation to acini and ducts. The sympathetic (cholinergic) VIP-containing neurons innervated blood vessels and exocrine tissue in the cat sweat glands. In the coeliac-superior mesenteric ganglion complex of the guinea pig and cat, a dense network of VIP-immunoreactive fibers was seen preferentially around noradrenergic ganglionic cell bodies lacking APP-immunoreactive material. Thus, adult peripheral sympathetic neurons can be subdivided into several categories on the basis of specific peptides. These subdivisions may innervate specific targets and may receive peptide-specific neuronal inputs.

Animals↗

The ultrastructural localization of serotonin immunoreactivity within the nucleus of the solitary tract of the cat.

Using a modification of the peroxidase-antiperoxidase technique, serotonin immunoreactivity was localized at the ultrastructural level in the nucleus of the solitary tract of the cat. Structures containing serotonin immunoreactivity included unmyelinated axons, varicosities (0.5 to 2 micrometers in diameter), and synaptic terminals. The serotonin-containing synaptic terminals were found less frequently than axons or varicosities. Within unmyelinated axons and varicosities, the immunoreactivity was associated mainly with large granular vesicles (80 to 150 nm). While large granular vesicles were found in all immunoreactive structures, greater numbers were observed in axons and nonsynaptic varicosities. Serial sections of several nonsynaptic serotonin-immunoreactive varicosities indicated the lack of synaptic specializations associated with these structures. In a typical section, only one or two granular vesicles were in synaptic terminals which contained numerous small clear vesicles. Serotonin-immunoreactive terminals formed asymmetrical contacts with dendrites and spines. No synaptic contacts involving immunoreactive terminals were found on cell bodies or other axonal structures. Serotonin-containing neuronal perikarya within the nucleus of the solitary tract were never observed. The abundance of nonsynaptic varicosities containing large granular vesicles suggests a possible neurohumoral role for serotonin within the feline nucleus of the solitary tract. This is discussed in relation to previous reports concerning the paucity of genuine synaptic contacts involving serotonin in other regions of the central nervous system. The presence of serotonin-immunoreactive terminals in the nucleus of the solitary tract also suggests its function as a putative neurotransmitter.

Animals↗

Localization of substance P-like immunoreactivity in cell bodies of the feline dorsal vagal nucleus.

Using the peroxidase-antiperoxidase (PAP) technique, substance P-like immunoreactivity (SPLI) was localized in the dorsal vagal nucleus as punctate varicosities in non-treated cats. In animals treated with colchicine 48 h prior to sacrifice, SPLI varicosities as well as significant numbers of cell bodies found throughout the entire extent of the dorsal vagal nucleus. Results of this study not only confirm the presence of SPLI in the dorsal vagal nucleus but also suggest a possible additional source of SPLI which has been reported to be present in the vagus nerve.

Animals↗

Immunohistochemical studies on the effect of capsaicin on spinal and medullary peptide and monoamine neurons using antisera to substance P, gastrin/CCK, somatostatin, VIP, enkephalin, neurotensin and 5-hydroxytryptamine.

After neonatal treatment of rats with capsaicin, the spinal cord, the spinal trigeminal nucleus and spinal and trigeminal ganglia were analysed with immunohistochemistry using antisera to several peptides and 5-hydroxytryptamine. A marked decrease was observed in substance P-, cholecystokinin-, somatostatin- and VIP-like immunoreactivity present in the central branches of primary sensory neurons in the spinal cord and in substance P- and somatostatin-like immunoreactivity in sensory ganglion cells. No definite depleting effect of capsaicin could be established on 5-hydroxytryptamine and peptides, such as enkephalin and neurotensin, present in centrally originating fibres in the dorsal horn of the spinal cord. The results demonstrate that the effects of capsaicin are not confined to substance P immunoreactive primary sensory neurons. The possibility is discussed that capsaicin effects specifically functioning rather than chemically specific primary sensory neurons.

Animals↗

Terminals of reserpine-sensitive vasopressin-neurophysin neurons in the external layer of the rat median eminence.

The indirect immunofluorescence technique was used to examine the pharmacology associated with reserpine-induced alterations in vasopressin and neurophysin (VP/NP) immunoreactivity in the external layer of the median eminence in the rat. Twenty-four hours after injection of reserpine, a selective, marked depletion of VP/NP immunoreactivity from the external layer is apparent. Pretreatment with the monoamine oxidase inhibitors, pargyline and tranylcypromine, prevents the depleting effect of reserpine, indicating that the acute effect of reserpine is mediated by monoamines. Acute intraventricular treatment with 6-hydroxydopamine, but not 5,7-dihydroxytryptamine, mimicked the reserpine effect, suggesting that catecholamines mediate reserpine depletion of VP/NP immunoreactivity from the external layer. The experimental results are consistent with a regulatory model in which catecholamines tonically inhibit VP/NP release from terminals in the external layer of the median eminence. Although the studies do not definitively determine the functional relationship between VP and ACTH, the anatomical location of these terminals, the dramatic change in the VP/NP content of these terminals in response to reserpine, and the lack of a response to dehydration suggest that this pool of vasopressin may contribute to ACTH hypersecretion in response to reserpine.

Animals↗

Relationship between enkephalinergic neurons and the vasopressin-oxytocin neuroendocrine system of the cat: an immunohistochemical study.

Localization of enkephalins and opiate binding sites in the central nervous system of rats has been reported by several authors. These studies did not reveal an extensive enkephalinergic system in the hypothalamo-hypophyseal axis of rats. The present paper reports on an extensive enkephalinergic system in the cat hypothalamo-hypophyseal system. Sections of paraformaldehyde fixed cat hypothalami were incubated with anti-methionine enkephalin serum, anti-vasopressin serum, and anti-oxytocin serum. Immunohistochemical localization of methionine enkephalin fibers and terminals in the median eminence, hypophyseal stalk, and pars nervosa was similar, but not identical to the distribution of vasopressin and oxytocin in these structures. Neuronal perikarya localized with the three antisera in the nucleus supraopticus and nucleus paraventricularis were of a similar size and morphology. In cats treated with colchicine prior to sacrifice, the anti-methionine enkephalin serum revealed a group of periventricular cell bodies. Cell bodies were not localized in this area with anti-vasopressin or anti-oxytocin sera. The functional significance of such an extensive enkephalinergic system in the cat hypothalamo-hypophyseal axis is discussed.

Animals↗

A radioimmunoabsorbent assay for plasma somatostatin.

A solid phase radioimmunoassay for determination of immunoreactive somatostatin (IRS) in plasma is described. Plasma samples obtained from 30 apparently healthy persons and from 5 anaesthetized pigs were extracted with acetone-petroleum ether. The antibodies (R 141 and R 101) were conjugated to cyanogenbromide activated microcrystalline cellulose. Tyr1-somatostatin was iodinated according to the lactoperoxidase method. After extraction the recovery of somatostatin varied between 80 and 118%. The sensitivity of the assay was 5--10 pg/ml and the intra- and interassay variation ranged between 8 and 20%. The mean (+/- S.D.) value of IRS in systemic blood in man was 77 (+/- 19) pg/ml. Intravenous administration of 10 micrograms/kg synthetic somatostatin to anaesthetized pigs was followed by a 20-fold increase in plasma IRS. The hypersomatostatinemia rapidly vanished with a half-life of 3.5 min. The level of IRS in cerebrospinal fluid was unchanged by intravenous somatostatin at this dose.

Animals↗