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U Arvidsson

Publications and source records attributed to U Arvidsson.

At least 19 recordsLinked to original sources
PubMed2000

Multiple messengers in descending serotonin neurons: localization and functional implications.

In the present review article we summarize mainly histochemical work dealing with descending bulbospinal serotonin neurons which also express a number of neuropeptides, in particular substance P and thyrotropin releasing hormone. Such neurons have been observed both in rat, cat and monkey, and may preferentially innervate the ventral horns of the spinal cord, whereas the serotonin projections to the dorsal horn seem to lack these coexisting peptides. More recent studies indicate that a small population of medullary raphe serotonin neurons, especially at rostral levels, also synthesize the inhibitory neurotransmitter gamma-amino butyric acid (GABA). Many serotonin neurons contain the glutamate synthesizing enzyme glutaminase and can be labelled with antibodies raised against glutamate, suggesting that one and the same neuron may release several signalling substances, causing a wide spectrum of post- (and pre-) synaptic actions.

Animals↗
PubMed1999

Differential expression of nerve terminal protein isoforms in VAChT-containing varicosities of the spinal cord ventral horn.

Of the different types of synaptic contacts with the mammalian spinal motoneuron, the synapse made by the cholinergic, so-called C-terminal of unknown origin and function has special morphological characteristics. Thus, in this synapse, there is no postsynaptic density but rather a large subsynaptic cistern in the motoneuron. To see whether this particular arrangement imposes special demands on the transmitter release machinery, we examined the presence of nerve terminal proteins in the C-terminal by using immunohistochemistry. Cholinergic nerve fibers and terminals in the spinal cord ventral horn were identified with an antiserum to the vesicular acetylcholine transporter (VAChT) protein. Immunohistochemistry in combination with confocal laser microscopy showed the presence of synaptosomal-associated protein of 25 kDa (SNAP-25)-, syntaxin-, cysteine string protein (CSP)-, synuclein-, synapsin I-, synapsin I/II-, synaptotagmin I-, synaptotagmin I/II-, synaptophysin-, and synaptobrevin-2-like immunoreactivity (-LI) in VAChT-containing C-terminals. Synaptotagmin III and synaptobrevin 1 could not be demonstrated in this type of terminal. VAChT-containing varicosities in the Renshaw cell area, with a probable origin from motoneuron axon collaterals, exhibited CSP, synapsin I/II, and synaptobrevin-1-LI, but not SNAP-25-, syntaxin-, synuclein-, synapsin I-, synaptotagmin I-, synaptotagmin I/II-, synaptophysin- and synaptobrevin-2-LI. The results suggest a differential content of nerve terminal proteins and their isoforms in cholinergic C-terminals apposing motoneurons and in the Renshaw cell area. It is concluded that C-terminals contain synaptic proteins necessary for fast transmitter release, and their origin should not be the motoneurons themselves.

Animals↗
PubMed1999

Visualization of time-dependent redistribution of delta-opioid receptors in neuronal cells during prolonged agonist exposure.

To date, the visualization of delta-opioid receptor (DOR) internalization has been largely focused on the events of short-term agonist treatment in transfected non-neuronal cells. In this study, we followed DOR trafficking upon prolonged agonist exposure in the neuronally derived neuro2a cells, stably transfected with the fusion DOR (HA-DOR) cDNA. Internalization of surface DOR was clearly visualized in 5 min of exposure to agonist (100 nM DADLE), and the cell surface DOR remained low throughout the entire 24 h agonist exposure. Significant intracellular accumulation was visible at 20 min exposure, and increased to a maximum at 4 h, after which intracellular DOR staining gradually diminished. DOR intracellular staining was enhanced in the presence of agonist and chloroquine, a lysosomotropic agent, suggesting that internalized receptors were targeted to lysosomes and degraded upon prolonged treatment. Time-dependent colocalization of DOR with transferrin and LAMP-2 following short-term and prolonged agonist exposure further confirmed that receptor was distributed to early endosomes (sequestration) and subjected to lysosomes for degradation (down-regulation), respectively.

Antibody Specificity↗
PubMed1998

Localization and regulation of the delta-opioid receptor in dorsal root ganglia and spinal cord of the rat and monkey: evidence for association with the membrane of large dense-core vesicles.

Using immunohistochemistry and immunoelectron microscopy, the localization and regulation of delta-opioid receptor-like immunoreactivity were studied in dorsal root ganglia and spinal cord of normal rat and monkey, and after peripheral axotomy. Delta-opioid receptor-like immunoreactivity was observed in many small dorsal root ganglion neurons, and in the rat most of them contained substance P and calcitonin gene-related peptide. At the ultrastructural level, delta-opioid receptor-like immunoreactivity was localized in the Golgi complex, on the membrane of the large dense-core vesicles and on the membrane of and/or inside a type of large vesicle with an interior of low electron density. The latter vesicles were often in contact with multivesicular bodies. In the superficial dorsal horn of the spinal cord, most delta-opioid receptor-positive nerve fibers contain substance P and/or calcitonin gene-related peptide, both in rat and monkey. Also, in these nerve endings delta-opioid receptor-like immunoreactivity was found on the membrane of large dense-core vesicles and on the membrane of, or in, the lucent vesicles. Occasionally, delta-opioid receptor-like immunoreactivity was observed on the plasmalemma of the terminals, particularly when the vesicles were in exocytotic contact with the plasmalemma. Peripheral axotomy induced a decrease in delta-opioid receptor-like immunoreactivity both in cell bodies in the dorsal root ganglia and in terminals in the dorsal horn. These data suggest that the delta-opioid receptor may be a constituent of the membrane of large dense-core vesicles storing and releasing neuropeptides. It is suggested that upon exocytotic release of substance P and calcitonin gene-related peptide from large dense-core vesicles, there is a transient modification of the surface of the primary afferent terminals which leads to exposure of the receptor protein so that enkephalin released from adjacent terminals can activate the receptor. The decrease in delta-opioid receptors after axotomy indicates that delta-opioid receptor-mediated inhibitory effects are attenuated at the spinal level both in the rat and monkey.

Animals↗
PubMed1997

Vesicular acetylcholine transporter (VAChT) protein: a novel and unique marker for cholinergic neurons in the central and peripheral nervous systems.

Acetylcholine (ACh) is synthesized in nerve terminals from choline and acetyl coenzyme A by the cytoplasmic enzyme choline acetyltransferase (ChAT). The neurotransmitter is thereafter transported into synaptic vesicles, where it is stored until release. cDNA clones encoding a vesicular ACh transporter (VAChT) were recently isolated. In this paper, we report on the generation of highly specific goat polyclonal antisera to the rat VAChT protein by using a synthetic carboxy-terminal 20-amino-acid peptide sequence as an immunogen. Characterization of the antisera revealed recognition of VAChT, but not vesicular monoamine transporter (VMAT) protein, in transfected CV-1 cells. VAChT immunoreactivity was also detected in cells that endogenously express the protein, such as in PC12 cells and in primary cultures of spinal motoneurons. Absorption controls showed that the VAChT antisera could be completely blocked at the 10(-5) M concentration by cognate peptide used for immunization. The antisera cross-reacted with the VAChT protein in rat and mouse but not in guinea pig, rabbit, or cat. Immunohistochemistry and confocal laser microscopy, using the goat VAChT antisera, showed strong immunoreactivity in discrete fibers and neuronal cell bodies of the central and peripheral nervous systems. Within cell bodies and axonal nerve terminals, as well as in dendrites, the staining appeared granular, presumably representing labeling of synaptic vesicles containing ACh. In the rat central nervous system, VAChT-positive cell bodies were demonstrated in the cerebral cortex, striatum, septum, nucleus basalis, medial habenula, mesopontine complex, cranial, and autonomic and spinal motor nuclei and in the intermediomedial region near the central canal. High densities of VAChT-immunoreactive axonal fibers were encountered in areas such as the olfactory bulb, cerebral cortex, striatum, basal forebrain, amygdala, thalamus, hypothalamus including median eminence, hippocampal formation, superior colliculus, interpeduncular nucleus, and pedunculopontine and laterodorsal tegmental nuclei. In cranial and spinal motor nuclei, particularly large varicosities were seen in close proximity to the motoneuron cell somata and their proximal dendrites. In the peripheral nervous system, VAChT immunoreactivity was also detected in motor endplates of skeletal muscle as well as in fibers of sympathetic and parasympathetic abdominal ganglia, heart atrium, respiratory tract, gastrointestinal tract, pancreas, adrenal medulla, male genitourinary tract, and salivary and lacrimal glands. Direct double labeling revealed colocalization of VAChT and ChAT immunoreactivity in neurons. The results show that VAChT antisera represent novel and unique tools for the study of cholinergic neurons in the central and peripheral nervous systems.

Animals↗
PubMed1997

Immunocytochemical localization of mu-opioid receptors in follicular cells and preimplantation mouse embryos.

It has been demonstrated that opioid peptides are involved in the regulation of mammalian reproduction. In our previous studies we demonstrated direct effects of opioids on preimplantation mouse embryos, and hypothesized the existence in preimplantation embryos of receptors similar to opioid receptors in the central neuronal system of adult animals. In the present study we addressed this issue by employing immunocytochemical staining for mu-opioid receptors using antisera raised against the C-terminal portion of the cloned mu-opioid receptors (MOR1, NHQLENLEAETAPLP, 384-398) predicted from the cloned receptor. Diffuse MOR1 immunoreactivity of moderate intensity has been revealed in one-cell embryos, while in follicular cells MOR1 staining was of high intensity and appeared to be associated with plasma membrane. No MOR1 immunoreactivity has been observed in two-cell to morula stages of development. However, blastocysts displayed intense MOR1-labeling that was particularly prominent in cells within the inner cell mass. MOR1-staining was most likely specific because preincubation of MOR1 antisera with cognate peptide completely abolished the staining. Our findings suggest the presence of opioid receptors during preimplantation development, long before the formation of the nervous system. Embryonic opioid receptors may play a role in the regulation of preimplantation development and implantation.

Animals↗
PubMed1996

mu-Opioid and delta-opioid receptors are expressed in brainstem antinociceptive circuits: studies using immunocytochemistry and retrograde tract-tracing.

Opioid-produced antinociception in mammals seems to be mediated in part by pathways originating in the periaqueductal gray (PAG) and the rostroventral medulla (RVM), and these pathways may include serotonergic neurons. In the present study, we examined the relationship of the cloned mu- and delta-receptors (MOR1 and DOR1, respectively) to PAG neurons projecting to the RVM, and RVM neurons projecting to the dorsal spinal cord. This was carried out by combining immunocytochemical staining for MOR1, DOR1, and serotonin with fluorescent retrograde tract-tracing. Of 133 retrogradely labeled cells in the RVM, 31% were immunoreactive for MOR1. Of the double-labeled cells, 41% also were immunoreactive for 5HT. Fifty-three percent of retrogradely labeled cells were apposed by DOR1-ir varicosities; 29% of the apposed cells were immunoreactive for 5HT. In the mesencephalon, cells retrogradely labeled from the RVM were usually surrounded by MOR1-ir structures; however, retrogradely labeled cells were never observed to be immunoreactive for MOR1. Similarly, retrogradely labeled cells in the caudal midbrain were seldom, if ever, labeled for DOR1; however, they frequently were apposed by DOR1-ir varicosities. Of 156 retrogradely labeled profiles from three rats, 52 (33%) were apposed by DOR1-ir varicosities. We conclude that both mu- and delta-opioid receptors could be involved in the antinociception mediated by the PAG-RVM-spinal cord circuit. In addition, opioids seem likely to have both direct and indirect effects on spinally projecting RVM cells in general, and on serotonergic RVM cells in particular.

Animals↗
PubMed1996

Immunofluorescence analysis of antisense oligodeoxynucleotide-mediated 'knock-down' of the mouse delta opioid receptor in vitro and in vivo.

We have previously used antisense oligodeoxynucleotides (ODN) to the cloned delta opioid receptor (DOR) to inhibit the antinociceptive response to spinally administered delta opioid receptor selective agonists in mice. Here we have examined the effect of DOR antisense ODN treatment on the level of DOR expressed in NG 108-15 cells and the spinal cord, through immuno-fluorescence microscopy, to determine the efficiency and selectivity of the antisense ODN-mediated "knock-down' of the DOR in these tissues. Antisense ODN, but not mismatch control, treatment resulted in a significant reduction in DOR immunoreactivity (-ir) in NG 108-15 cells and spinal cord. Thus, the inhibition of antinociceptive response to intrathecal delta selective agonists by DOR antisense ODN correlates with the loss of DOR-ir in the superficial layers of the dorsal horn of the spinal cord.

Animals↗
PubMed1996

Differential distribution of two ATP-gated channels (P2X receptors) determined by immunocytochemistry.

Several P2X receptor subunits were recently cloned; of these, one was cloned from the rat vas deferens (P2X1) and another from pheochromocytoma (PC12) cells differentiated with nerve growth factor (P2X2). Peptides corresponding to the C-terminal portions of the predicted receptor proteins (P2X1 391-399 and P2X2 460-472) were used to generate antisera in rabbits. The specificities of antisera were determined by staining human embryonic kidney cells stably transfected with either P2X1 or P2X2 receptors and by absorption controls with the cognate peptides. In the vas deferens and the ileal submucosa, P2X1 immunoreactivity (ir) was restricted to smooth muscle, whereas P2X2-ir was restricted to neurons and their processes. Chromaffin cells of the adrenal medulla and PC12 cells contained both P2X1- and P2X2-ir. P2X1-ir was also found in smooth muscle cells of the bladder, cardiac myocytes, and nerve fibers and terminals in the superficial dorsal horn of the spinal cord. In contrast, P2X2-ir was observed in scattered cells of the anterior pituitary, neurons in the hypothalamic arcuate and paraventricular nuclei, and catecholaminergic neurons in the olfactory bulb, the substantia nigra, ventral tegmental area, and locus coeruleus. A plexus of nerve fibers and terminals in the nucleus of the solitary tract contained P2X2-ir. This staining disappeared after nodose ganglionectomy, consistent with a presynaptic function. The location of the P2X1 subunit in smooth muscle is consistent with its role as a postjunctional receptor in autonomic transmission, while in neurons, these receptors appear in both postsynaptic and presynaptic locations.

Amino Acid Sequence↗
PubMed1996

[The hormone leptin reduces body weight. A mutant gene makes the mouse obese].

The existence of mice (ob/ob mice) with a genetic defect causing obesity and type II diabetes has been known since 1950. The mutated ob gene was recently identified and characterized. The gene encodes a 167 amino acid protein that has been given the name leptin, from the greek word leptos, meaning thin. The functionally active hormone, which is synthesised and secreted by adipocytes, is lacking in homozygote ob/ob mice, causing an increase in body fat. Injection of recombinant leptin in ob/ob mice induces loss of fat due to decreased appetite and increased energy expenditure. The ob gene product leptin acts via binding sites in the hypothalamus, where the centre for appetite and satiety is located. Research is now focused on the identification, characterization and cloning of leptin-receptors. Other mice, also with a genetic defect causing obesity and type II diabetes, do not respond to leptin treatment and are therefore suspected to have defective leptin receptors.

Animals↗
PubMed1995

Increase in alpha-CGRP and GAP-43 in aged motoneurons: a study of peptides, growth factors, and ChAT mRNA in the lumbar spinal cord of senescent rats with symptoms of hindlimb incapacities.

Sprague-Dawley rats develop progressive motor dysfunctions during the third year of life. We use this as a model to examine possible neuronal mechanism(s) that may cause motor impairments occuring during aging. In this study we have used indirect immunofluorescence histochemistry (IF) and in situ hybridization histochemistry (ISH) to study quantitatively and qualitatively the staining pattern and mRNA expression of calcitonin gene-related peptide (alpha-CGRP), growth-associated protein 43 (GAP-43), and acidic fibroblast growth factor (aFGF) in spinal lumbar motoneurons of young adult (2-3 months) and aged (30 months) Sprague-Dawley rats. In addition, mRNAs encoding choline acetyltransferase (ChAT), beta-CGRP, and cholecystokinin (CCK) were analyzed. All aged rats used in this study disclosed symptoms of hindlimb incapacity, ranging from mild weight-bearing insufficiency to paralysis of the hind limbs. The symptoms were confined to the musculature of the hindlimb and hip regions. Only a small number (approximately 15%) of the large motoneurons that innervate the hindlimb muscles were lost in those aged rats that had clinical symptoms of hindlimb motor incapacities. The remaining motoneurons expressed ChAT mRNA at levels similar to those of young adult rats. The vast majority of these motoneurons showed increased mRNA levels for alpha-CGRP and GAP-43. Aged motoneurons contained more CGRP like immunoreactivity (LI), but the number of immunoreactive neurons was smaller than in adult rats. GAP-43-LI could be detected in motoneurons in aged, but not in adult, rats. GAP-43-LI was always colocalized with CGRP-LI in aged motoneurons. Studies of individual aged rats revealed that the increase of GAP-43 mRNA-positive cell bodies occurred in cases with the most severe clinical symptoms, whereas the increase in alpha-CGRP was even evident in rats with mild symptoms. No alterations in content of aFGF-LI or aFGF mRNA could be detected in the aged rat, and the content of CCK and beta-CGRP mRNAs was also normal. The usefulness of this rat model for studies of neuromuscular aging and possible functional roles for GAP-43 and CGRP in plastic and regenerative processes during aging are discussed.

Aging↗
PubMed1995

The kappa-opioid receptor is primarily postsynaptic: combined immunohistochemical localization of the receptor and endogenous opioids.

Antisera were raised against a synthetic peptide corresponding to the carboxyl terminus of the kappa-opioid receptor (KOR1). Specificity of the antisera was verified by staining of COS-7 cells transfected with KOR1 and epitope-tagged KOR1 cDNAs, by recognition by the antisera of proteins on Western blots of both transfected cells and brain tissue, by the absence of staining of both brain tissue and transfected cells after preabsorption of the antisera with the cognate peptide, and on the strong correlation between the distribution of KOR1 immunoreactivity and that of earlier ligand binding and in situ hybridization studies. Results indicate that KOR1 in neurons is targeted into both the axonal and somatodendritic compartments, but the majority of immunostaining was seen in the somatodendritic compartment. In sections from rat and guinea pig brain, prominent KOR1 staining was seen in the ventral forebrain, hypothalamus, thalamus, posterior pituitary, and midbrain. While the staining pattern was similar in both species, distinct differences were also observed. The distribution of preprodynorphin and KOR1 immunoreactivity was complementary in many brain regions, suggesting that KOR1 is poised to mediate the physiological actions of dynorphin. However, the distribution of KOR1 and enkephalin immunoreactivity was complementary in some regions as well. These results suggest that the KOR1 protein is primarily, but not exclusively, deployed to postsynaptic membranes where it mediates the effects of products of preprodynorphin and possibly preproenkephalin.

Amino Acid Sequence↗
PubMed1995

Distribution of neuropeptide receptors. New views of peptidergic neurotransmission made possible by antibodies to opioid receptors.

The cloning of receptors for neuropeptides made possible studies that identified the neurons that utilize these receptors. In situ hybridization can detect transcripts that encode receptors and thereby identify the cells responsible for their expression, whereas immunocytochemistry enables one to determine the region of the plasma membrane where the receptor is located. We produced antibodies to portions of the predicted amino acid sequences of delta, mu, and kappa opioid receptors and used them in combination with antibodies to a variety of neurotransmitters in multicolor immunofluorescence studies visualized by confocal microscopy. Several findings are notable: First, the cloned delta opioid receptor appears to be distributed primarily in axons, and therefore most likely functions in a presynaptic manner. Second, the cloned mu and kappa opioid receptors are found associated with neuronal plasma membranes of dendrites and cell bodies and therefore most likely function in a postsynaptic manner. However, in certain, discrete populations of neurons, mu and kappa opioid receptors appear to be distributed in axons. Third, enkephalin-containing terminals are often found in close proximity (although not necessarily synaptically linked) to membranes containing either the delta or mu opioid receptors, whereas dynorphin-containing terminals are often found in proximity to kappa opioid receptors. Finally, a substantial mismatch between opioid receptors and their endogenous ligands was observed in some brain regions. However, this mismatch was characterized by complementary zones of receptor and ligand, suggesting underlying principles of organization that underlie long-distance, nonsynaptic neurotransmission.

Afferent Pathways↗
PubMed1995

Immunohistochemical localization of delta- and mu-opioid receptors in primate spinal cord.

Immunofluorescent techniques were used to examine the distribution of delta- and mu-opioid receptor-like immunoreactivity (ir) in primate spinal cord. At every segmental level examined, opioid receptor-ir formed a dense plexus of small profiles within the superficial dorsal horn. delta-Opioid receptor-ir was found in laminae I and II, whereas mu-opioid receptor-ir was confined mostly to lamina II. The distribution of opioid receptors within the superficial dorsal horn is appropriate for a localization to the central terminals of thinly myelinated and unmyelinated sensory neurons. Differences in the distribution of the delta- and mu-opioid receptors may reflect the presence of these two opioid receptor types on different functional classes of afferent neurons, or they may relate to differences in presynaptic and postsynaptic localization within the spinal gray matter.

Animals↗
PubMed1995

delta-Opioid receptor immunoreactivity: distribution in brainstem and spinal cord, and relationship to biogenic amines and enkephalin.

We have recently developed antisera which recognize epitopes of the cloned delta-opioid receptor (DOR; Dado et al., 1993). In the present report we have further characterized these antisera, and raised additional antisera in rats. We used these antisera to determine the distribution of DOR-like immunoreactivity (-Ll) in rat spinal cord and brainstem in relation to serotoninergic, noradrenergic, and enkephalinergic neurons. We found DOR-Ll in fibers and varicosities distributed throughout the spinal cord gray matter, with highest densities in the superficial dorsal horn, in autonomic regions, around the central canal as well as in the ventral horn motor nuclei. In the brainstem a dense innervation of DOR-immunoreactive (-IR) fibers was found in several nuclei such as spinal trigeminal nuclei, midline raphe nuclei, parabrachial nuclei, periaqueductal gray matter (PAG), interpeduncular nucleus, ans substantia nigra. A group of DOR-positive cells was seen in the laterodorsal tegmental nucleus. In addition, a few DOR-IR cell bodies were demonstrated in the parabrachial nuclei, interpeduncular nucleus, PAG, and superior and inferior colliculi as well as around the central canal in the spinal cord. All DOR-positive cells showed a punctuate staining pattern within the cytoplasm of the cell body and in primary dendrites. No plasma membrane staining of cells or dendrites could be demonstrated using the DOR antisera. Double-labeling experiments for DOR and 5-hydroxytryptamine (5HT, serotonin) revealed that some 5HT-IR neurons in the raphe complex were surrounded by DOR-IR fibers. In the spinal cord a high degree of coexistence was found between DOR and 5HT in nerve fibers and varicosities in the neuropil around the motoneurons and in lamina V of the dorsal horn. In autonomic regions of the spinal cord, a low degree of colocalization was seen between DOR and 5HT; in the superficial dorsal horn no coexistence was found. Tyrosine hydroxylase (TH)-positive neurons in the brainstem (in the A5 area, locus coeruleus, and A7 area) were apposed by DOR-positive fibers. However, no coexistence could be seen between DOR and TH in any part of the spinal cord. A close relation, but no coexistence, was observed between DOR- and enkephalin (ENK)-IR fibers in the spinal cord ventral horn; in the intermediolateral nucleus a low degree of colocalization was observed. Thus, a delta-opioid receptor may affect the activity of descending serotoninergic and noradrenergic neurons by means of modulating the release of neurotransmitters from afferents to these neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1995

Distribution and targeting of a mu-opioid receptor (MOR1) in brain and spinal cord.

Opioid receptors regulate neuronal activity by both pre- and postsynaptic mechanisms. We recently reported that the cloned delta-opioid receptor (DOR1) is primarily targeted to axons, suggesting a presynaptic role. In the present study we have studied the distribution and targeting of another opioid receptor, the mu-opioid receptor (MOR1), by raising anti-peptide antisera to the C-terminal peptide of MOR1. The specificity of the antisera was determined by analysis of transfected cells, Western blots, and immunoisolation studies. Immunohistochemistry showed that MOR1 immunoreactivity was enriched in many brain areas including cerebral cortex, striatum, hippocampus, locus coeruleus, and the superficial laminae of the dorsal horn. Moreover, MOR1-expressing neurons seem to target this receptor preferentially to their somatodendritic domain as determined by double-labeling experiments with MAP2. However, discrete populations of neurons target MOR1 to their axons, including some primary afferent neurons that express DOR1. In many regions enkephalin-containing axons were complementary to MOR1, suggesting by their proximity that enkephalins may be physiologically relevant ligands for this receptor. Thus, these results provide a morphological basis for understanding pre- and postsynaptic functions mediated by MOR1.

Afferent Pathways↗
PubMed1994

Localization of neuropeptide Y Y1 receptors in the rat nervous system with special reference to somatic receptors on small dorsal root ganglion neurons.

Immunohistochemical staining with an antiserum against the neuropeptide Y (NPY)-Y1 receptor (Y1-R) protein was shown in rat small dorsal root ganglion (DRG) neurons, which also were Y1-R mRNA-positive and calcitonin gene-related peptide (CGRP)-positive. The Y1-R-like immunoreactivity was almost exclusively located in the somatic plasmalemma and in the perinuclear region. Intracellular recording showed that the Y1 agonist [Leu31,Pro34]NPY evoked an outward current in small DRG neurons, suggesting a functional somatic Y1-R. No evidence for axonal transport of Y1-R protein was obtained after analysis of the dorsal horn for double staining with CGRP, after dorsal rhizotomy, or after compression of dorsal roots and the sciatic nerve. It is proposed that blood-borne NPY released from sympathetic nerves and adrenal medulla is the endogenous ligand for the Y1 receptors on the small DRG neurons. Y1-R-positive neurons were also seen in the dorsal horn of spinal cord, the hypothalamic arcuate nucleus, pyramidal cells in the cerebral cortex, Purkinje and basket cells in the cerebellar cortex, and in many other brain regions.

Animals↗