Biomedical subjects

E Senba

Publications and source records attributed to E Senba.

At least 127 records · Page 7Linked to original sources

PubMed1990

RNA levels of neuronal nicotinic acetylcholine receptor subunits are differentially regulated in axotomized facial motoneurons: an in situ hybridization study.

In situ hybridization histochemistry using complementary RNA probes revealed that alpha 3 and beta 2 neuronal nicotinic acetylcholine receptor subunit mRNAs were expressed in 12% and 40% of facial motoneurons of the rat, respectively. The alpha 3 subunit mRNA signals disappeared in response to axotomy, whereas the beta 2 subunit mRNA signal was remarkably enhanced, suggesting that mRNA levels of receptor subunits are differentially regulated in axotomized motoneurons.

Animals↗

PubMed1990

Alpha-CGRP and beta-CGRP mRNAs are differentially regulated in the rat spinal cord and dorsal root ganglion.

We found an increase in calcitonin gene-related peptide (CGRP)-like immunoreactivity in motoneurons of rat spinal cord after peripheral axotomy. By means of in situ hybridization histochemistry and Northern blotting, we further demonstrated that this increase was the result of increased levels of alpha-CGRP mRNA, not beta-CGRP mRNA. The increased level of alpha-CGRP mRNA was maintained for at least 5 weeks, and was present on both sides. In addition, alpha-CGRP and beta-CGRP mRNAs had different distributions from each other in the dorsal root ganglia and levels of both were decreased after axotomy. These results indicate that alpha-CGRP and beta-CGRP are regulated independently and have different roles in the motor and sensory systems of the spinal cord.

Animals↗

PubMed1990

Localization of neuropeptide precursor-synthesizing neurons in the rat olfactory bulb: a hybridization histochemical study.

The distribution of seven kinds of neuropeptide precursor mRNA-containing neurons was investigated in the rat main and accessory olfactory bulbs, where various peptides have previously been identified immunohistochemically, by means of in situ hybridization using [35S]cRNA probes. In the glomerular layer, numerous preprothyrotropin-releasing hormone mRNA-expressing neurons, moderate numbers of preprosomatostatin and preproenkephalin A neurons, and a small number of preprocholecystokinin neurons were detected. In the external plexiform layer, numerous medium sized preprocholecystokinin and preprocorticotropin-releasing hormone neurons, and a small number of beta-preprotachykinin A neurons were observed. In addition, small preprovasoactive intestinal polypeptide and preprothyrotropin-releasing hormone neurons were evenly distributed in the external plexiform layer. Medium to large sized beta-preprotachykinin A neurons formed a thin layer in the mitral cell layer. In the granule cell layer, in addition to numerous small preproenkephalin A neurons, moderate numbers of small beta-preprotachykinin A and preprocorticotropin-releasing hormone neurons, and a small number of preprothyrotropin-releasing hormone neurons, were identified. Large sized preprosomatostatin neurons were located in the deep layer of the granule cell layer. The distribution patterns of these neurons, as a whole, confirmed previous studies based on immunohistochemistry, although peptide precursor mRNA-expressing neurons were far more numerous than those immunoreactive to the respective neuropeptides. Moreover, mRNA-expressing neurons were observed in areas where no immunoreactive neurons had been observed (e.g. preprovasoactive intestinal polypeptide and preprosomatostatin neurons in the mitral cell layer of the assessory olfactory bulb). The distribution patterns were generally similar in the main and accessory olfactory bulbs.

Animals↗

PubMed1990

Calcium-binding proteins calbindin and parvalbumin in the superficial dorsal horn of the rat spinal cord.

Neurons containing the calcium-binding proteins, calbindin or parvalbumin, were studied by immunohistochemistry in the superficial dorsal horn of the rat spinal cord. Calbindin-containing cells were found in laminae I, II and III, being more abundant in laminae I and II. Some of the neurons in lamina I containing calbindin projected to the supraspinal area. Parvalbumin-containing neurons were mainly distributed in laminae IIi and III. Calbindin and parvalbumin were not detected in the same cells. Some 75% of the neurotensin-like immunoreactive neurons contained calbindin, which corresponded to 13% of the calbindin-containing neurons. Calbindin was sometimes found in the same cells with substance P, enkephalin or somatostatin but less frequently (44-46% of the peptide-containing neurons). Parvalbumin was not found together with these peptides. Electron microscopy showed that the immunoreactive products of calbindin or parvalbumin were mostly in the dendrites or cell bodies. Immunoreactive axon terminals were relatively few. In rhizotomized animals, neurons containing one of these proteins in laminae II and III were found to receive direct inputs of primary afferent fibers. These findings indicate that neurons containing these two proteins belong to different subpopulations of dorsal horn neurons. They may be important in primary afferent processing.

Animals↗

PubMed1990

Cell types and axonal sizes of calcitonin gene-related peptide-containing primary sensory neurons of the rat.

Neurons with immunoreactivity (IR) for calcitonin gene-related peptide (CGRP) in the rat dorsal root ganglia were examined by immunoelectron microscopy. About one-half of the neurons of the L5 dorsal root ganglia of animals treated with colchicine had CGRP-IR, and 40% of these were large neurons of type A. The proximal parts of their peripheral axons were, however, unmyelinated (91%) or thinly myelinated (9%). Thickly myelinated axons observed in the same sections were always devoid of CGRP-IR. The CGRP-IR neurons were various subtypes of type A and B neurons. No specific morphological characteristics were associated with CGRP-IR.

Animals↗

PubMed1989

Localization, origin and fine structure of calcitonin gene-related peptide-containing fibers in the vestibular end-organs of the rat.

The localization, origin and fine structure of nerve terminals immunoreactive for calcitonin gene-related peptide (CGRP) were examined in the vestibular end-organs of rats using immunocytochemistry. Many CGRP-like immunoreactive (CGRP-IR) fibers were observed in the vestibular sensory epithelial layer. By electronmicroscopy, CGRP-IR terminals were found to make synaptic contacts with the chalyces of the vestibular nerves terminating on type I cells. The origin of these vestibular CGRP-IR fibers was examined by a combination of a retrograde fiber tracing technique (using Fast blue) and immunocytochemistry. Injections of the tracer into the vestibular cistern, resulted in fast blue-labeled neurons bilaterally in the area dorsolateral to the genu of the facial nerve; these labeled neurons also contained CGRP. These findings indicate that CGRP-IR fibers originate bilaterally from the area dorsolateral to the genu of the facial nerve and that CGRP plays a modulatory role in the transmission of vestibular information from type I cells.

Animals↗

PubMed1989

Calcitonin gene-related peptide- and substance P-containing primary afferent fibers in the dorsal column of the rat.

The dorsal column and its nuclei exhibit a considerable number of fibers containing neuropeptides, such as calcitonin gene-related peptide (CGRP) and substance P (SP), whose origins and functional roles are as yet unknown. The present study attempts to determine the origin and nature of these fibers by means of immunohistochemistry combined with several experimental manipulations. A similar study was done on scattered substance P (SP) fibers whose presence was confirmed in this study. Transection of the upper cervical cord of rats resulted in an accumulation of CGRP, sometimes with SP also, in the caudal aspect of the lesion, thus indicating the presence of peptide-containing ascending fibers. Hemitransection of the dorsal column at the level of C2-3 caused reduction of CGRP-containing fibers in the dorsal column and its nuclei on the operated side. Electron microscopic observation of the nucleus gracilis revealed that CGRP-like immunoreactive terminals made direct axodendritic synaptic contacts. Medium- to large-sized neurons in the dorsal root ganglia were labeled with Fast blue dye which was injected into the dorsal column nuclei. These included medium- to large-sized neurons exhibiting immunoreactivity to CGRP-like substances, and neurons of a medium size which were immunoreactive to SP-like compounds. The incidence of the former was higher at the thoracic level than at the cervical and lumbar levels, while that of the latter was very low. Electron microscopic observation of CGRP-containing fibers in the cervical region of the dorsal column revealed that 88% of these fibers were unmyelinated and the remainder were thinly myelinated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Proenkephalin opioid peptide product in the sensory ganglia of the rat: a developmental immunohistochemical study.

The distribution and development of Met-enkephalin-Arg6-Gly7-Leu8 (Enk-8)-containing neurons in the sensory ganglia of the rat were investigated by means of immunocytochemistry using specific antiserum to this octapeptide. Enk-8-like immunoreactivity first appeared in neurons of the trigeminal ganglia of the 18-day embryo, then in the dorsal root ganglia of the 21-day embryo, thus exhibiting a rostrocaudal gradient in terms of appearance and abundance. The number of immunoreactive neurons in these sensory ganglia peaked on the 5th-7th postnatal days, with several small ones observed in each section (1.0-1.4% of total cell number). About 30-40% of these Enk-8-like immunoreactive neurons were also immunoreactive to substance P. Subsequently, Enk-8-like immunoreactivity in the sensory ganglia was decreased and was rarely detected in adult animals. However, colchicine treatment revealed the presence of several Enk-8-containing neurons per section prepared from mature rat. All these neurons were small (12.5-25 microns; mean +/- S.E.M., 19.86 +/- 3.26 microns). Some of these were also immunoreactive to substance P. These results strongly suggest that the preproenkephalin A system exists in subpopulations of both developing and matured sensory cells in the rat. Functional significance of this is discussed.

Aging↗

PubMed1989

Distribution and fine structure of calcitonin gene-related peptide-like immunoreactive nerve fibers in the rat skin.

Distribution of calcitonin gene-related peptide-like immunoreactive (CGRPI) nerve fibers and their fine structure were examined in the skin of rat foot pads using immunocytochemistry. The CGRPI fibers formed bundles in the dermis and subcutaneous tissue. Two types of single-stranded CGRPI fibers were seen to leave the fiber bundles: one was located along the blood vessels or around the eccrine sweat glands, while the other entered the epidermis directly or through the Meissner's corpuscles in the dermal papillae. CGRPI fibers in the epidermis were distributed widely and were occasionally associated with Merkel cells. Immunoelectron microscopic study revealed that CGRPI fibers located around blood vessels, sweat glands, epidermal keratinocytes and Merkel cells, or in the Meissner's corpuscles did not form typical synaptic contacts with underlying cells, despite being varicose and filled with vesicles resembling synaptic ones. These findings suggested that the CGRP is released non-synaptically from these terminals to influence diffusely the organs surrounding the terminals. These cutaneous fibers seemed to originate from CGRPI neurons (both small type B cells and large type A cells) in the dorsal root ganglia (DRG), because injection of fast blue dye into the cutaneous nerve resulted in labeling of these CGRPI cells in the DRG and excision of the L3-L6 DRG resulted in the non-detection of cutaneous CGRPI fibers in the foot pads. Analysis of the composition of CGRPI fibers found in the rat skin has revealed that these are mostly unmyelinated. C-type fibers with some of them being thin myelinated fibers. This was true even of CGRPI fibers at the proximal end of peripheral neurites of the DRG.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Terminal field of cholecystokinin-8-like immunoreactive projection neurons of the rat main olfactory bulb.

The terminal field of cholecystokinin-8 (CCK)-like immunoreactive (CCK-IR) tufted cells in the rat main olfactory bulb was examined by means of immunohistochemistry combined with either an anterograde tracer or a degeneration method. CCK immunostaining was carried out in animals in which Phaseolus vulgaris agglutinin (PHA) had been injected into the main olfactory bulb. Pairs of adjacent sections were processed for CCK and PHA immunostaining, respectively. Dense CCK-IR terminallike staining was noted in layer Ia of the anterior olfactory nucleus and lateral part of the olfactory tubercle; weaker staining was also observed in the transitional area between the anterior olfactory nucleus and the piriform cortex, in the medial part of the olfactory tubercle, and in the cortical amygdaloid nucleus. The CCK-IR staining was limited to the area containing PHA-labeled terminals and was diminished in these sites after unilateral olfactory bulbectomy. Immuno-electron microscopic analysis showed that CCK-IR profiles in such regions made asymmetric synaptic contacts, mainly with dendritic spines. These results suggest that CCK-IR tufted cells project mainly to the anterior olfactory nucleus and lateral part of the olfactory tubercle, and act mainly via axospinous synapses.

Animals↗

PubMed1989

Calcitonin gene-related peptide containing sympathetic preganglionic and sensory neurons projecting to the superior cervical ganglion of the rat.

The origin of calcitonin gene-related peptide (CGRP)-containing fibers observed in the superior cervical ganglia (SCG) of the rat was investigated by a combined technique of retrograde axonal tracing and indirect immunofluorescence. Following the injection of Fast blue (FB) into the SCG, labeled neurons were observed in the C8-T5 spinal cord segments, with the highest density in T1-T3 (5-8 neurons per section). More than 90% of them were located in the ipsilateral intermediolateral cell column (IML) and the rest were found in the central autonomic area (CA) and intercalated region (IC) between the IML and CA. CGRP-like immunoreactive (IR) neurons were detected in these areas in animals pretreated with colchicine. About one-fourth of FB-labeled cells were CGRP-IR, which corresponded to three-fourths of the CGRP-IR neurons in the above-mentioned autonomic areas of these spinal cord segments. Most of these double-labeled cells were found in the IML (95%). A few FB-labeled cells were also observed in dorsal root ganglia (C8-T5) and 30% of them were CGRP-IR. These findings suggested that the CGRP-IR fibers in the rats SCG are supplied from both sympathetic preganglionic neurons in the spinal cord and sensory ganglion cells, although the latter projection is quite rare.

Amidines↗

PubMed1989

Distribution of neuropeptidelike immunoreactivities in the guinea pig olfactory bulb.

The distribution of neuropeptidelike immunoreactivities in the adult guinea pig olfactory bulb was studied immunohistochemically with antisera raised against neurotensin (NT), substance P (SP), methionine-enkephalin-Arg6-Gly7-Leu8 (ENK), somatostatin (SOM), neuropeptide Y (NPY), and cholecystokinin-8 (CCK). In the main olfactory bulb, NT-like immunoreactive (NT-IR) neurons were found among periglomerular cells. In addition, a few periglomerular cells showed ENK-like immunoreactivity. Granule cells displaying SP- or ENK-like immunoreactivities and short axon cells with SOM- or NPY-like immunoreactivities were observed in the deeper half of the granule cell layer. SOM-IR short axon cells were also seen in the external plexiform layer. Dense NT- or NPY-IR fibers were distributed in superficial lamina of the granule cell layer, and sparse SP- or CCK-IR fibers were found in the glomerular layer. In the accessory olfactory bulb, some mitral, periglomerular, and granule cells showed NT-like immunoreactivity. SP- or ENK-IR granule cells were also observed. These results are discussed in relation to laminar organization of the olfactory bulb. The most characteristic features of peptide distribution in guinea pigs, as compared with that of rats in previous studies, were the relative abundance of NT-IR structures and the lack of SP- and CCK-IR juxtaglomerular and tufted cells.

Animals↗

PubMed1989

Laminar and segregated distribution of immunoreactivities for some neuropeptides and adenosine deaminase in the superior colliculus of the rat.

The distribution and morphology of adenosine deaminase, substance P, leucine-enkephalin, corticotropin-releasing factor, and calcitonin gene-related peptidelike immunoreactive cells and fibers throughout the superior colliculus of the rat were examined by means of the unlabelled-antibody peroxidase-antiperoxidase method. Adenosine deaminase immunoreactive cells were found in the stratum opticum and lower stratum griseum superficiale; substance P immunoreactive cells were localized to the upper stratum griseum superficiale, and calcitonin gene-related peptide immunolabelled neurons were situated in deeper strata. Substance P, leucine-enkephalin, and calcitonin gene-related peptide immunoreactive fibers were distributed similarly in their lamination and in their patchlike organization. Corticotropin-releasing factor immunoreactive fibers were observed evenly throughout all the strata and were fewer in the stratum griseum superficiale. These findings suggest that, as in afferent modules and segregated efferents of the mammalian superior colliculus, the cells and fibers containing neuroactive substances and neuroactive substance-related enzymes also show a segregated and laminar distribution.

Adenosine Deaminase↗

PubMed1989

Adenosine deaminase containing fiber pathway from the superior colliculus to the lateral posterior nucleus of the rat.

Presence of a projection containing adenosine deaminase (ADA)-like immunoreactivity from the stratum opticum (SO) to the dorsomedial portion of the lateral posterior nucleus of the thalamus (LPN) of the rat was demonstrated using a method combining retrograde tracing by horseradish peroxidase (HRP) and immunohistochemistry for ADA. In the caudal two thirds of the LPN, a clearly delimited ADA-like immunoreactive fiber plexus was located. Injection of HRP into the lateral posterior nucleus labeled many neurons in the medial portion of the SO where medium-sized neurons with ADA immunoreactivity were concentrated. Simultaneous immunostaining showed that some of the HRP-labeled neurons are ADA-positive.

Adenosine Deaminase↗

PubMed1989

Prepro-VIP and preprotachykinin mRNAs in the rat dorsal root ganglion cells following peripheral axotomy.

Using in situ hybridization histochemistry, we examined the expression of prepro-vasoactive intestinal polypeptide (VIP) mRNAs and preprotachykinin (PPT) mRNAs which coded for substance P (SP) in the rat dorsal root ganglion (DRG) following spinal nerve transection. VIP mRNAs increased dramatically in the DRG neurons after transection of the peripheral branch of the spinal nerve (sciatic nerve), whereas PPT mRNAs showed a gradual decrease for a few weeks. Dorsal rhizotomy or axotomy of the central branch of DRG cells had little influence on VIP-mRNAs and no effect on PPT mRNA expression. These results demonstrated an activation of VIP biosynthesis in the DRG neurons due to axotomy of the peripheral branch, which was opposite to the reaction of PPT mRNA to the same treatment.

Animals↗

PubMed1989

Ultrastructural investigation of substance P-, leucine-enkephalin- and 5-hydroxytryptamine-like immunoreactive terminals in the area of cremaster motoneurons of the male rat.

Studies were made on whether substance P-, leucine-enkephalin- and 5-hydroxytryptamine (serotonin)-like immunoreactive fibers exert a direct influence on the cremaster motoneurons of the male rat by immunocytochemistry combined with retrograde tracing at the light- and electron-microscopic levels. Horseradish peroxidase was used as a retrograde tracer. Two days after injection of horseradish peroxidase into the genitofemoral nerves, its accumulation in the cremaster motoneurons was demonstrated by the diaminobenzidine-nickel method. On immunocytochemical examination of the same sections immunoreactive end-products were detected by the peroxidase-antiperoxidase method. Two different kinds of reaction products were distinguishable at both the light- and electron-microscopical levels. The horseradish peroxidase-labeled cremaster motoneurons at the L1 and L2 levels of the spinal cord were surrounded by abundant immunoreactive terminals. Examination at the ultrastructural level showed that substance P-like immunoreactive terminals formed synaptic contacts almost exclusively with the proximal dendrites of these horseradish peroxidase-labeled cremaster motoneurons. On the other hand, in the leucine-enkephalin- and serotonin-like boutons, significant numbers of axosomatic contacts with horseradish peroxidase-labeled cells were seen although axodendritic contacts with horseradish peroxidase-labeled cells were predominant. Occasionally, leucine-enkephalin-like immunoreactive fibers with synapses on horseradish peroxidase-labeled neurons formed axoaxonic contacts with other leucine-enkephalin-like axonal terminals. Thus, substance P-, leucine-enkephalin- and serotonin-like fibers clearly regulate the function of cremaster motoneurons monosynaptically. The varied synaptic contacts of these fibers according to the neuroactive substances involved suggest different actions of these substances on the cremaster motoneurons.

Animals↗

PubMed1989

Localization and origins of calcitonin gene-related peptide containing fibres in the vestibular end-organs of the rat.

The distribution, origin and fine structure of nerve terminals immunoreactive to calcitonin gene-related peptide (CGRP) were investigated in the vestibular end-organs of the rat by means of immunocytochemistry. Dense plexus of CGRP-like immunoreactive (CGRPI) fibres were observed just beneath the sensory epithelial layers of the ampullary crista of the semicircular canal, and utricular and saccular maculae of the otolith organ. Some CGRPI fibres left the plexus to enter the sensory epithelial layer. Parasagittal transection of the brain just medial to the cochlear nucleus revealed the presence of a few CGPRI fibres in the vestibular end-organs ipsilaterally, indicating that these fibres originate in the central nervous system. A combination of retrograde tracing and immunocytochemistry was then used to identify the origins of CGRPI fibres found in the vestibular end-organs. After injection of fast blue dye (FB) into the vestibular cistern, CGRPI neurons in the area dorsolateral to the genu of the facial nerve were labelled by FB bilaterally. The present ultrastructural study has revealed that most of the CGRPI fibres in the vestibular end-organs form direct contacts with afferent nerve terminals which surround type I vestibular sensory cells.

Acoustic Maculae↗

PubMed1988

Co-localization of substance P and Met-enkephalin-Arg6-Gly7-Leu8 in the intraspinal neurons of the rat, with special reference to the neurons in the substantia gelatinosa.

A double-labeling immunofluorescence technique was employed to investigate the co-localization of the functionally antagonistic neuropeptides, substance P and enkephalins, within intraspinal neurons of the rat. Anti-Met-enkephalin-Arg6-Gly7-Leu8 (Enk-8) antiserum was used as a marker of the preproenkephalin A neuron system. The observations were focused on the lumbar spinal cord. Co-localization was most prominent within neurons in the substantia gelatinosa, in which more than 95% of substance P-like immunoreactivity neurons showed Enk-8-like immunoreactivity. These double-labeled cells corresponded to 45% of Enk-8-like immunoreactive neurons in the same area. This suggests that SP/Enk-8 interaction occurs at the axon terminals of the substantia gelatinosa neurons. In deeper layers of the dorsal horn (laminae III, IV), only 14% and 6% of SP-like immunoreactive and Enk-8-like immunoreactive neurons were double labeled, respectively. Co-localization was also observed in neurons located in the laminae I, V, VII and X, suggesting concomitant involvement of these peptides in a variety of spinal cord functions.

Animals↗