Galanin Immunoreactivity Research Articles

Immunohistochemical characterization of nerve elements in porcine intrinsic laryngeal ganglia.

The present study investigated the chemical coding of neurons and nerve fibres in local laryngeal ganglia in pigs (n=5) using double-labelling immunohistochemistry. Virtually all the neurons were cholinergic in nature (ChAT- or VAChT-positive). Only very solitary, small nerve cells (presumably representing interneurons) stained intensely for adrenergic marker, DβH. Many neurons also contained immunoreactivity for NOS (91%), VIP (62.7%), NPY (24.7%), galanin (10%), SP (1.3%) and CGRP (5.3%). No neurons expressing somatostatin or Leu-enkephalin were observed. Nearly all the neuronal somata were densely supplied with varicose cholinergic nerve terminals, which presumably represented preganglionic axons, and some of them were also closely apposed with CGRP- and/or SP-positive varicose nerve endings, which were putative collaterals of extrinsic primary sensory fibres. In conclusion, this study has revealed that intrinsic neurons in the porcine larynx, like in many other mammalian species studied, should be classified as parasympathetic cholinergic neurons expressing biologically active substances, predominantly NOS and VIP. Furthermore, they are likely to receive inputs from not only preganglionic neurons but also primary sensory nerve cells. Finally, it appears that the information on the occurrence of the local laryngeal ganglia should be regularly included in textbooks dealing with the cranial portion of the parasympathetic nervous system in mammals.

Long‐term hypercapnia does not alter Galanin immunoreactivity in mouse brain respiratory and chemoreceptor regions

Long‐term hypercapnia has been implicated in respiratory disorders such as sleep apnea and chronic obstructive pulmonary disease (COPD). However, the mechanisms by which long‐term hypercapnia contributes to central respiratory dysfunction in these conditions are unclear. The brainstem respiratory circuit, including the ventral respiratory column (VRC), comprises distinct neuronal populations that govern expiratory and inspiratory drive. The neuropeptide galanin is extensively distributed in brainstem chemoreceptor regions and the VRC, and microinjection of galanin into the VRC inhibits breathing and attenuates ventilatory reflex responses to acute hypercapnia. Nevertheless, the normal pattern of regional expression of galanin in the mouse brain is not known and the impact of long‐term hypercapnia on galanin immunoreactivity (Gal‐ir) in the vicinity of brainstem respiratory and chemoreceptor regions has not yet been studied. Therefore, we aimed to determine Gal‐ir across the mouse brain and investigate the impact of prolonged hypercapnia exposure on Gal‐ir in brainstem respiratory and chemoreceptor regions (pons and medulla). Adult male Phox2b‐EGFP (MGI ID: 5776545) mice (31±2 g, n=5 mice/group) were exposed to hypercapnia (8% CO2; balance room air) or room air (control) for 10 or 14 days. To determine Gal‐ir, brain slices were collected and processed for immunohistochemistry. Quantitative measurement of Gal‐ir was performed using ImageJ 1.53a (a QuPath‐integrated version of ImageJ) where a positive area fraction, reflecting the proportion of positively labeled pixels, was calculated for each region of interest [locus coeruleus, the retrotrapezoid nucleus, caudal‐nucleus of the solitary tract (cNTS), rostral‐NTS (rNTS), VRC, lateral reticular nucleus, and caudoventrolateral reticular nucleus]. Under control conditions, we found that Gal‐ir was broadly present across the medulla oblongata, and abundant in the caudal aspects when compared with the rostral levels. The cNTS had a higher average percentage of Gal‐ir area (p = 0.043, p = 0.05, 2‐way ANOVA) compared to rNTS following 10‐ and 14‐days of room air exposure, respectively. A significant difference in Gal‐ir (p = 0.011, 2‐way ANOVA) was observed between the cNTS and rNTS following 14‐days of hypercapnia exposure. Overall, there was no significant difference of Gal‐ir in all regions assessed after long‐term hypercapnia compared to controls. Collectively, we found that long‐term hypercapnia does not induce changes in galanin neuropeptide levels within respiratory and chemoreceptor regions in the mouse brain. Under control and hypercapnia conditions, cNTS contains higher Gal‐ir compared to rNTS. Further investigation is required to elucidate the involvement of NTS‐galaninergic subsets in respiratory homeostasis.

Substance P-Immunoreactive Fiber Varicosities Appear to Innervate Galaninergic Perikarya in the Human Hypothalamus.

Introduction: Substance P (SP) is a member of the tachykinin family. In the central nervous system, SP participates among others, in the regulation of pain, learning, memory, emotion, and sexual functions. In the periphery, SP affects the gastrointestinal, cardiovascular, and urinary systems. Galanin, similarly to SP, appears to be involved in wide range of physiologic functions, including cognition, waking and sleep, feeding, mood, blood pressure, reproduction, and development, where acts as a trophic factor. The similar distribution of SP-immunoreactive (SP-IR) fibers and galanin-IR perikarya in the human hypothalamus suggests functional interaction between these neuropeptides. Methods: We have utilized double-label immunohistochemistry to reveal these putative juxtapositions. Results: The majority of galanin-IR neurons receive contacting SP-IR fibers that often cover a significant area of the galaninergic perikarya forming multiple en passant type contacts. These SP-galanin juxtapositions are located mainly in the basal part of the infundibulum/median eminence, populating the basal periventricular region as well as the basal perifornical area. Discussion: The density and the morphology of these associations suggest that these contacts are functional synapses and therefore may represent the morphological substrate of the control of SP on multiple functions regulated/modulated by galanin. SP via galanin may modulate anterior pituitary hormone secretion, as contrary to SP, high density of galanin immunoreactivity is present in the median eminence, and by innervating galanin-IR neurons projecting to other parts of the brain, SP can modulate indirectly their activities. Impact statement The present study is the first describing juxtapositions between the substance P (SP)-immunoreactive (IR) and galanin-IR neurons in the human hypothalamus. These juxtapositions may be functional synapses and they may represent the morphological substrate of the control of SP on the galaninergic system. SP via galanin may modulate anterior pituitary hormone secretion, as contrary to SP, high density of galanin immunoreactivity is present in the median eminence. Galanin, released into the hypothalamo-hypophyseal circulation, can reach the anterior pituitary and function as a hypophysiotropic substance and regulates anterior pituitary hormone secretion. SP by innervating galanin-IR neurons, which project to other parts of the brain, can modulate indirectly their activities.

Galanin System in Human Glioma and Pituitary Adenoma.

Expression of neuropeptides and their corresponding receptors has been demonstrated in different cancer types, where they can play a role in tumor cell growth, invasion, and migration. Human galanin (GAL) is a 30-amino-acid regulatory neuropeptide which acts through three G protein-coupled receptors, GAL1-R, GAL2-R, and GAL3-R that differ in their signal transduction pathways. GAL and galanin receptors (GALRs) are expressed by different tumors, and direct involvement of GAL in tumorigenesis has been shown. Despite its strong expression in the central nervous system (CNS), the role of GAL in CNS tumors has not been extensively studied. To date, GAL peptide expression, GAL receptor binding and mRNA expression have been reported in glioma, meningioma, and pituitary adenoma. However, data on the cellular distribution of GALRs are sparse. The aim of the present study was to examine the expression of GAL and GALRs in different brain tumors by immunohistochemistry. Anterior pituitary gland (n = 7), pituitary adenoma (n = 9) and glioma of different WHO grades I–IV (n = 55) were analyzed for the expression of GAL and the three GALRs with antibodies recently extensively validated for specificity. While high focal GAL immunoreactivity was detected in up to 40% of cells in the anterior pituitary gland samples, only one pituitary adenoma showed focal GAL expression, at a low level. In the anterior pituitary, GAL1-R and GAL3-R protein expression was observed in up to 15% of cells, whereas receptor expression was not detected in pituitary adenoma. In glioma, diffuse and focal GAL staining was noticed in the majority of cases. GAL1-R was observed in eight out of nine glioma subtypes. GAL2-R immunoreactivity was not detected in glioma and pituitary adenoma, while GAL3-R expression was significantly associated to high-grade glioma (WHO grade IV). Most interestingly, expression of GAL and GALRs was observed in tumor-infiltrating immune cells, including neutrophils and glioma-associated macrophages/microglia. The presence of GALRs on tumor-associated immune cells, especially macrophages, indicates that GAL signaling contributes to homeostasis of the tumor microenvironment. Thus, our data indicate that GAL signaling in tumor-supportive myeloid cells could be a novel therapeutic target.

Coordinated Targeting of Galanin Receptors on Cholangiocytes and Hepatic Stellate Cells Ameliorates Liver Fibrosis in Multidrug Resistance Protein 2 Knockout Mice

Galanin (Gal) is a peptide with a role in neuroendocrine regulation of the liver. In this study, we assessed the role of Gal and its receptors, Gal receptor 1 (GalR1) and Gal receptor 2 (GalR2), in cholangiocyte proliferation and liver fibrosis in multidrug resistance protein 2 knockout (Mdr2KO) mice as a model of chronic hepatic cholestasis. The distribution of Gal, GalR1, and GalR2 in specific liver cell types was assessed by laser-capture microdissection and confocal microscopy. Galanin immunoreactivity was detected in cholangiocytes, hepatic stellate cells (HSCs), and hepatocytes. Cholangiocytes expressed GalR1, whereas HSCs and hepatocytes expressed GalR2. Strategies were used to either stimulate or block GalR1 and GalR2 in FVB/N (wild-type) and Mdr2KO mice and measure biliary hyperplasia and hepatic fibrosis by quantitative PCR and immunostaining of specific markers. Galanin treatment increased cholangiocyte proliferation and fibrogenesis in both FVB/N and Mdr2KO mice. Suppression of GalR1, GalR2, or both receptors in Mdr2KO mice resulted in reduced bile duct mass and hepatic fibrosis. Invitro knockdown of GalR1 in cholangiocytes reduced α-smooth muscle actin expression in LX-2 cells treated with cholangiocyte-conditioned media. A GalR2 antagonist inhibited HSC activation when Gal was administered directly to LX-2 cells, but not via cholangiocyte-conditioned media. These data demonstrate that Gal contributes not only to cholangiocyte proliferation but also to liver fibrogenesis via the coordinate activation of GalR1 in cholangiocytes and GalR2 in HSCs.

Galanin immunoreactivity is sexually polymorphic in neuroendocrine and vocal-acoustic systems in a teleost fish.

Galanin is a peptide that regulates pituitary hormone release, feeding, and reproductive and parental care behaviors. In teleost fish, increased galanin expression is associated with territorial, reproductively active males. Prior transcriptome studies of the plainfin midshipman (Porichthys notatus), a highly vocal teleost fish with two male morphs that follow alternative reproductive tactics, show that galanin is upregulated in the preoptic area-anterior hypothalamus (POA-AH) of nest-holding, courting type I males during spawning compared to cuckolding type II males. Here, we investigate possible differences in galanin immunoreactivity in the brain of both male morphs and females with a focus on vocal-acoustic and neuroendocrine networks. We find that females differ dramatically from both male morphs in the number of galanin-expressing somata and in the distribution of fibers, especially in brainstem vocal-acoustic nuclei and other sensory integration sites that also differ, though less extensively, between the male morphs. Double labeling shows that primarily separate populations of POA-AH neurons express galanin and the nonapeptides arginine-vasotocin or isotocin, homologues of mammalian arginine vasopressin and oxytocin that are broadly implicated in neural mechanisms of vertebrate social behavior including morph-specific actions on vocal neurophysiology in midshipman. Finally, we report a small population of POA-AH neurons that coexpress galanin and the neurotransmitter γ-aminobutyric acid. Together, the results indicate that galanin neurons in midshipman fish likely modulate brain activity at a broad scale, including targeted effects on vocal motor, sensory and neuroendocrine systems; are unique from nonapeptide-expressing populations; and play a role in male-specific behaviors.

Distribution Patterns of Cocaine- and Amphetamine-Regulated Transcript- and/or Galanin-Containing Neurons and Nerve Fibers Located in the Human Stomach Wall Affected by Tumor.

The aim of the study was to investigate the distribution patterns of cocaine- and amphetamine-regulated transcript- (CART-) and galanin-immunoreactive (GAL-IR) neuronal structures in the human stomach wall, focusing on differences observed in regions directly affected by the cancer process, and those from the surgical margin. Samples from the stomach wall were collected from 10 patients (3 women and 7 men, the mean age 67.0 ± 11.9). Next, triple-immunofluorescence staining was used to visualize the changes in the frequency of neurons inside myenteric plexi and intramural fibers containing CART and/or GAL, as well as protein gene product 9.5 (as panneuronal marker). Tumor into the stomach wall caused a decrease in the number of CART-positive (+) nerve fibers in the longitudinal (LML) and circular muscle layers (CML). Notable changes in the dense network of CART+/GAL+ nerve fibers (an increase) were observed in the LML and lamina muscularis mucosae (LMM) within carcinoma-affected areas of the human stomach. Additionally, an elevated number of these nerve fibers from LMM were accompanied by an increase in the number of fibers containing GAL in the vicinity of the neoplastic proliferation. Obtained results suggest that a carcinoma invasion may affect the innervation pattern of the human stomach wall and their function(s).

Exploring the transcriptome of resident spinal microglia after collagen antibody-induced arthritis.

Recent studies have suggested a sexually dimorphic role of spinal glial cells in the maintenance of mechanical hypersensitivity in rodent models of chronic pain. We have used the collagen antibody-induced arthritis (CAIA) mouse model to examine differences between males and females in the context of spinal regulation of arthritis-induced pain. We have focused on the late phase of this model when joint inflammation has resolved, but mechanical hypersensitivity persists. Although the intensity of substance P, calcitonin gene-related peptide, and galanin immunoreactivity in the spinal cord was not different from controls, the intensity of microglia (Iba-1) and astrocyte (glial fibrillary acidic protein) markers was elevated in both males and females. Intrathecal administration of the glial inhibitors minocycline and pentoxifylline reversed mechanical thresholds in male, but not in female mice. We isolated resident microglia from the lumbar dorsal horns and observed a significantly lower number of microglial cells in females by flow cytometry analysis. However, although genome-wide RNA sequencing results pointed to several transcriptional differences between male and female microglia, no convincing differences were identified between control and CAIA groups. Taken together, these findings suggest that there are subtle sex differences in microglial expression profiles independent of arthritis. Our experiments failed to identify the underlying mRNA correlates of microglial actions in the late phase of the CAIA model. It is likely that transcriptional changes are either subtle and highly localised and therefore difficult to identify with bulk isolation techniques or that other factors, such as changes in protein expression or epigenetic modifications, are at play.

Stress-specific changes of galanin and PACAP expression in the rat hypothalamus and adrenal gland

Galanin and pituitary adenylate cyclase-activating peptide (PACAP) are involved in the stress response, and both produce multiple effects in the central and peripheral nervous systems. In rodents, galanin brain expression is altered by different stressors, while PACAP has a critical role in the circuits mediating the stress-response. The aim of this study was to investigate whether acute and/or repeated immobilization (IMO) and restraint (R) differently affect galanin and PACAP expression in the rat hypothalamus and adrenal gland. Relative expression of mRNAs was examined by qPCR and relative changes in the protein content were analyzed using Western blotting. The distribution of galanin and PACAP peptides in the hypothalamus was analyzed by immunofluorescence. Relative hypothalamic expression of both galanin and PACAP mRNAs was increased only after repeated restraint. Hypothalamic galanin protein levels were increased after all applied stressors, whereas there were no changes in the PACAP content. In the adrenal glands, galanin and PACAP mRNAs were elevated only after acute IMO, whereas the protein levels were not changed, regardless of the applied stressor or its duration. Immunofluorescence staining demonstrated the presence of galanin in the paraventricular nuclei (PVN) of the hypothalamus in all groups. Galanin immunoreactivity was stronger in the PVN of all stressed groups in comparison to the control. We concluded that the patterns of transcriptional activation and translational control of galanin and PACAP in the examined tissues depended on the type (IMO vs. R) and duration (acute vs. repeated) of the applied stressor.

UVB irradiation induces rapid changes in galanin, substance P and c-fos immunoreactivity in rat dorsal root ganglia and spinal cord

Recent studies have shown that UVB irradiation induces primary and secondary hyperalgesia in rats and humans peaking about 24h after UVB exposure. In the present study we investigated the changes in galanin, substance P and c-fos immunoreactivity in rat DRG and spinal cord at the L5 level 2–96h after UVB irradiation. UVB irradiation of the heel area in rats almost increased the skin blood flow two-fold 24h after irradiation as measured by laser Doppler technique. UVB irradiation induced a significant reduction of the proportion of galanin positive DRG neurons for all time points, except at 12h. In the spinal cord, UVB irradiation induced increased immunoreactivity for galanin in the dorsal horn, the area around the central canal and interestingly also in the lateral spinal nucleus 12–96h after exposure. For substance P the proportion of substance P positive neurons was unchanged but UVB irradiation induced increased substance P immunoreactivity in the dorsal part of the spinal cord 48h after irradiation. UVB irradiation also induced c-fos immunoreactivity in the dorsal horn and the area around the central canal 24 and 48h after exposure. This translational model of UVB irradiation will induce rapid changes of neuropeptides implicated in nociceptive signaling in areas known to be of importance for nociception in a time frame, about 24h after exposure, where also neurophysiological alteration have been described in humans and rats.

Colorectal cancer patients exhibit increased levels of galanin in serum and colon tissues.

Galanin (GAL) is a 30-amino acid neuropeptide that is expressed in both the central and peripheral nervous system, including the enteric nervous system (ENS). Increased GAL concentrations have been identified in the blood of colorectal cancer (CRC) patients. The aim of the present study was to assess whether sections of the colon wall containing ENS plexuses or CRC tumor are associated with increased GAL concentrations. Blood samples were collected from 68 CRC patients and 39 healthy volunteers. In addition, samples of CRC tumors and colon wall tissue in close proximity to and distant from the neoplastic tissue were obtained from 22 CRC patients. The GAL concentration of sera and tissue homogenates obtained from three sections of the colon wall (mucosa with submucosa, muscularis externa and CRC tumor) was analyzed by ELISA. The localization of GAL was evaluated using immunohistochemistry and morphometry was used to measure the distribution of GAL-immunoreactive (GAL-Ir) myenteric plexuses in the vicinity of cancer invasion and in sections of the colon wall distant from the tumor. The GAL serum concentration of CRC patients was 2.4 times higher than that of the control group. The GAL concentration was highest in the homogenates of neoplastic tissue and mucosa obtained from the control (distant) section of the intestinal wall, followed by that in the mucosa and muscularis externa proximal to the tumor. The lowest GAL concentrations were identified within the muscular layer of the colon wall located distant from the tumor. Strong GAL immunoreactivity was identified in the cancer cells, intestinal epithelium and the submucosal and myenteric plexuses. Morphometric analysis revealed that the GAL-Ir myenteric plexuses in the vicinity of tumor infiltration were significantly smaller in size than those in the intact section of the large intestine. Furthermore, no associations were identified between the clinicopathological characteristics of CRC patients and GAL serum and tissue concentration. The increased GAL serum concentrations observed in CRC patients in comparison to healthy controls may result from GAL secretion by CRC tumors, however, other sources of GAL cannot be excluded. The atrophy of myenteric plexuses within close proximity to the tumor may affect the colon function of CRC patients. In conclusion, investigation into the presence of GAL in the colon wall and serum of CRC patients revealed that serum and tissue GAL levels may present useful potential biomarkers in CRC patients.

Galanin - Immunoreactive Nerve Fibers in the Mucosal Layer of the Canine Gastrointestinal Tract During Inflammatory Bowel Disease

Abstract The effect of inflammatory bowel disease (IBD) on the density of galanin - immunoreactive (GAL-IR) nerve fibers was determined in the mucosa of canine duodenum, jejunum, and descending colon. Fiber density was evaluated by a single immunofluorescence method in biopsy specimens obtained from healthy dogs and patients with variable severity of the disease. The density of GAL-IR nerve fibers was determined by the semi-quantitative method by counting fibers in the field of view (0.l mm2). Fiber density was higher in dogs with moderate and severe IBD than in healthy animals. The results of the study suggest that GAL present in intestinal nerve fibers could play a role in the pathogenesis and development of canine IBD.

Myenteric plexuses atrophy in the vicinity of colorectal cancer tissue is not caused by apoptosis or necrosis.

The previously performed studies showed that the presence of colorectal cancer (CRC) tumor is associated with the atrophy of myenteric plexuses in the vicinity of cancer invasion; however, the possible mechanisms of this phenomenon are not known. The aim of the present study was to determine whether the atrophic changes of the enteric nervous system (ENS) within an intestine wall of the CRC patients were caused by apoptosis or necrosis and whether they were associated with changes in the number of galanin-immunore-active (GAL-Ir) neurons. Samples of the large intestine wall located close to the CRC invasion and control, distally-located part of the colon, were collected from 9 CRC patients. The size of ENS plexuses and the number of neurons were compared. Triple immunofluorescent staining was used to visualize the co-expression of caspase 3 (CASP3) or caspase 8 (CASP8) with GAL and protein gene-product 9.5 (PGP 9.5, panneuronal marker) in the submucosal and myenteric ENS plexuses. The cells expressing myeloperoxidase (MPO, marker of neutrophils) and CD68 (marker of macrophages) were detected by immunohistochemistry around/in myenteric plexuses (MPs) and in the muscularis externa of the colon wall in the vicinity of tumor invasion. Myenteric plexuses in the vicinity of the CRC tissue were significantly smaller and had lower number of neurons per plexus than distantly located plexuses. The number of CASP8- and CASP3-Ir neurons in the ENS plexuses was similar in the colon wall both close to and distally from tumor invasion. The number of CASP8-Ir neurons within MPs located close to CRC invasion was higher than of CASP3-Ir neurons. The percentage of neurons co-expressing CASP8 and GAL in myenteric plexuses close and distantly from tumor was three-fold lower than of those co-expressing CASP3 and GAL. The mean number of neutrophils and macrophages inside and around myenteric plexuses located close to tumor invasion was higher or similar, respectively, as compared with adjacent muscularis externa. The atrophy of myenteric plexuses in the vicinity of CRC invasion is not caused by apoptosis or necrosis. The differences in the proportions of neurons expressing galanin and the studied caspases suggest as yet unknown role of this neuropeptide in the mechanisms of neuron's atrophy in MPs located close to CRC tumor.

Confocal imaging of autonomic preganglionic neurons in the spinal cord of the caecilian Typhlonectes natans (Amphibia: Gymnophiona)

Little is known about the spinal sympathetic organization in the caecilian amphibians. We examined for the first time the location of sympathetic preganglionic neurons (SPNs) in the spinal cord using a panel of specific markers expressed in SPNs. The SPNs of anuran amphibians form two cell columns segregated mainly in the lateral and medial marginal areas of the central gray matter. In the caecilian Typhlonectes natans immunoreactivity for galanin and ChAT is found in most laterally arranged neurons lying in spinal segments 2–7. They are encircled by TH- and nNOS-immunoreactive nerve fibers. These neurons might project specifically to a population of adrenergic sympathetic postganglionic neurons in paravertebral ganglia and/or non-adrenergic sympathetic postganglionic neurons in the celiac ganglia. However the segmental restriction and target specificity of the neurons of the species studied are not known. As mucous and granular glands in the dermis may represent one of the peripheral targets of the adrenergic ganglion cells and reflect the prominent preganglionic cell columns, an immunohistochemical study was done also on these glands. Retrograde-tracing studies are, however, needed to study the segmental localization of the preganglionic neurons and their projections to the postganglionic neurons in sympathetic ganglia.

Sa1700 Inhibition of the Substance P/Neurokinin 1 Receptor Signaling Axis Reduces Cholangiocarcinoma Growth In Vivo

A S L D A b st ra ct s increase in circulating Galanin in the serum. Galanin immunoreactivity was observed in both cholangiocytes and hepatocytes, whereas GalR1 was found predominantly in cholangiocytes. Systemic treatment of rats with M617 increased both CK-19 expression and IBDM in both sham and BDL-treated animals. In vitro, treatment of the mouse cholangiocyte cell line with M617 increased ERK1/2 and RSK-1 activity. There was a concomitant increase in cholangiocyte proliferation after M617 treatment that could be blocked by pretreatment with inhibitors for ERK1/2 and RSK-1. Conclusions: Data presented here demonstrate a direct stimulatory role for Galanin on cholangiocyte proliferation under physiological (sham) and pathological (BDL) conditions via a mechanism involving the activation of ERK1/2 and subsequent phosphorylation of RSK-1. Targeting Galanin or GalR1 may prove a useful strategy to regulate biliary mass during cholestatic liver injury.

Sa1699 Local Inhibition of Hepatic GnRH by Vivo-Morpholino Reduces Biliary Proliferation and Ameliorates the Expression of Fibrotic Markers in Cholestatic Rats

A S L D A b st ra ct s increase in circulating Galanin in the serum. Galanin immunoreactivity was observed in both cholangiocytes and hepatocytes, whereas GalR1 was found predominantly in cholangiocytes. Systemic treatment of rats with M617 increased both CK-19 expression and IBDM in both sham and BDL-treated animals. In vitro, treatment of the mouse cholangiocyte cell line with M617 increased ERK1/2 and RSK-1 activity. There was a concomitant increase in cholangiocyte proliferation after M617 treatment that could be blocked by pretreatment with inhibitors for ERK1/2 and RSK-1. Conclusions: Data presented here demonstrate a direct stimulatory role for Galanin on cholangiocyte proliferation under physiological (sham) and pathological (BDL) conditions via a mechanism involving the activation of ERK1/2 and subsequent phosphorylation of RSK-1. Targeting Galanin or GalR1 may prove a useful strategy to regulate biliary mass during cholestatic liver injury.

Sa1698 Downregulation of Menin by Mir-24-1 Increases Cholangiocarcinoma Proliferation

A S L D A b st ra ct s increase in circulating Galanin in the serum. Galanin immunoreactivity was observed in both cholangiocytes and hepatocytes, whereas GalR1 was found predominantly in cholangiocytes. Systemic treatment of rats with M617 increased both CK-19 expression and IBDM in both sham and BDL-treated animals. In vitro, treatment of the mouse cholangiocyte cell line with M617 increased ERK1/2 and RSK-1 activity. There was a concomitant increase in cholangiocyte proliferation after M617 treatment that could be blocked by pretreatment with inhibitors for ERK1/2 and RSK-1. Conclusions: Data presented here demonstrate a direct stimulatory role for Galanin on cholangiocyte proliferation under physiological (sham) and pathological (BDL) conditions via a mechanism involving the activation of ERK1/2 and subsequent phosphorylation of RSK-1. Targeting Galanin or GalR1 may prove a useful strategy to regulate biliary mass during cholestatic liver injury.

Galanin immunoreactivity in the brain of the desert lizard Uromastyx acanthinura during activity season

The distribution of galanin immunoreactive perikarya and nerve fibers in the brain of the desert lizard U. acanthinura was studied by means of immunofluorescence using an antiserum against rabbit galanin. The animals were captured during the activity season in March (wet season) just before reproduction period and in June (arid season) after ovulation period. Immunoreactive neurons were mostly detected in the mediobasal and the infundibular recess nuclei, the nucleus of the paraventricular organ, the paraventricular organ, the periventricular nucleus and in the anterior hypothalamus at the level of the periventricular nucleus, the paraventricular nucleus and the supraoptic nucleus. The differences in brain galanin expression between animals collected under both sets of environmental conditions indicated changes which occur during the annual and reproductive cycles. The wide hypothalamic and extrahypothalamic distribution of galanin immunoreactive fibers suggests that this peptide may have hypophysiotropic, neuromodulator and neurotransmitter roles in the lizard U. acanthinura.

Effects of neural androgen receptor disruption on aggressive behavior, arginine vasopressin and galanin systems in the bed nucleus of stria terminalis and lateral septum

In the present study, we investigated the role of the androgen receptor (AR) in the nervous system in the regulation of aggressive behavior and arginine vasopressin and galanin systems by testosterone. For this purpose, we used a conditional mouse line selectively lacking AR gene in the nervous system, backcrossed onto the C57BL/6J strain. Adult males were gonadectomized and supplemented with similar amounts of testosterone. When tested on two consecutive days in the resident intruder paradigm, fewer males of the mutant group exhibited aggressive behavior compared to their control littermates. In addition, a high latency to the first offensive attack was observed for the few animals that exhibited fighting behavior. This alteration was associated with a normal anogenital chemoinvestigation of intruder males. In olfactory discrimination tasks, sexual experience enhanced preference towards female-soiled bedding rather than male-soiled bedding and estrus females rather than intact males, regardless of genotype. This indicated that the behavioral alteration induced by neural AR mutation occurs in brain areas located downstream from the olfactory bulb. Quantification of the sexually dimorphic cell populations expressing preprovasopressin and galanin mRNAs in the bed nucleus of stria terminalis (BNST) and vasopressin-neurophysin 2 and galanin immunoreactivity in the lateral septum showed no significant differences between the two genotypes.The present findings indicate that the neural AR is required in the expression of aggressive behavior but not in the sexual differentiation of AVP and galanin cell number in the BNST and fiber immunoreactivity in the lateral septum. They also suggest that AR in the nervous system could mediate activational effects of testosterone in the regulation of aggressive behavior during adulthood.

Nicotine withdrawal upregulates nitrergic and galaninergic activity in the rat dorsal raphe nucleus and locus coeruleus

The dorsal raphe nucleus (DRN), a major source of forebrain serotonin, mediates various neural functions including anxiety. The nucleus locus coeruleus (LC) is likewise involved in mediating central components of the stress response and anxiety. An anxiety-reducing effect is widely believed to underlie many cases of nicotine dependence. While much is known about nicotine-serotonin interactions, little is known about how nicotine engages the DRN non-serotonergic domain in specific physiological functions that influence organismal behavior. The aim of this study was to determine how chronic nicotine withdrawal influences neuronal nitric oxide (NO) synthase (nNOS) and galanin immunoreactivity in the DRN and LC of adult rats. Compared with saline, nicotine increased nicotinamide adenine dinucleotide phosphate diaphorase profiles within distinct DRN subregions and also enhanced intensity in nNOS and galanin cell bodies in the rostral DRN as well as galanin in the LC. Nicotine-induced nNOS/galanin staining of somata was abundant in the rostral ventromedial DRN. Galanin-positive terminals surrounded nNOS-containing cell bodies in the DRN lateral wing subregions. These observations suggest that the DRN NOS-galanin domain and galanin in the LC are engaged in the organism's neural adaptation to chronic nicotine exposure. Hence NO and galanin synthesized or released within the DRN and LC or at the respective target sites might regulate the whole animal behavioral response to nicotine exposure.