Coeliac-superior Mesenteric Ganglion Research Articles

Organ-specific Sympathetic Innervation Defines Visceral Functions.

The autonomic nervous system orchestrates the brain and body functions through the sympathetic and parasympathetic pathways. However, our understanding of the autonomic system, especially the sympathetic system, at the cellular and molecular levels is severely limited. Here, we show unique topological representations of individual visceral organs in the major abdominal sympathetic ganglion complex. Using multi-modal transcriptomic analyses, we identified distinct sympathetic populations that are both molecularly and spatially separable in the celiac-superior mesenteric ganglia (CG-SMG). Notably, individual CG-SMG populations exhibit selective and mutually exclusive axonal projections to visceral organs, targeting either the gastrointestinal (GI) tract or secretory areas including the pancreas and bile tract. This combinatorial innervation pattern suggests functional segregation between different CG-SMG populations. Indeed, our neural perturbation experiments demonstrated that one class of neurons selectively regulates GI food transit. Another class of neurons controls digestion and glucagon secretion independent of gut motility. These results reveal the molecularly diverse sympathetic system and suggest modular regulations of visceral organ functions through distinct sympathetic populations.

Noninvasive focused ultrasound stimulation of the celiac-superior mesenteric ganglion complex regulates inflammation in murine endotoxemia

The nervous system has an important role in the regulation of cytokines and inflammation ( Nature, 2002). The celiac-superior mesenteric ganglion complex (CSMGC) is an important component of the vagus nerve based inflammatory reflex, which controls inflammation ( Nat Neuroscience 2017). In addition to receiving cholinergic innervations from the efferent vagus nerve, the CSMGC is innervated by preganglionic sympathetic splanchnic nerves, which also are involved in the inflammatory regulation. Both neuronal types - vagal and preganglionic sympathetic - interact with catecholaminergic neurons, which reside in this ganglionic complex and innervate the liver, spleen, and other abdominal organs. Despite being a prominent locus of neuronal interactions, the possibilities of directly targeting the CSMGC to regulate cytokine responses and inflammation remains unexplored. To provide insight, we subjected the CSMGC in mice to focused ultrasound stimulation (FUS) - a non-invasive approach, which has been increasingly utilized in neuromodulation. We used ultrasound imaging and doppler to localise the complex in anesthetized 10–14-week-old male C57BL/6J mice. To perform stimulation, the FUS transducer was placed on the abdominal surface over the CSMGC and FUS (1.1MHz and 200mV per pulse, 150 burst cycles, 500μs burst period) or sham stimulation was delivered for 2 mins or 5 mins. Five mins post FUS, mice were injected with lipopolysaccharide (endotoxin, 0.25mg/kg, i.p.) and euthanized after 90 mins. Blood and liver were collected and processed for cytokine analysis. Compared to sham stimulation, FUS of the CSMGC for 5mins (n=11,12/group) significantly decreased serum TNF levels (1,875 ± 750 pg/ml vs 672.9 ± 335 pg/ml, P< 0.0001) and hepatic TNF levels (27.8 ± 8.6 pg/mg vs 16.0 ± 7.1 pg/mg, P= 0.0018) in endotoxemic mice. In contrast, FUS of CSMGC for 2 mins (n=15/group) did not significantly alter serum TNF levels (1,458 ± 599.9 pg/ml vs 1,120 ± 332.5 pg/ml, P=0.1607). These results demonstrate the anti-inflammatory effcacy of noninvasive FUS of the CSMGC. Our findings also identify the CSMGC as an easily targetable new therapeutic site for controlling systemic and hepatic inflammation with a potential for clinical translation. This work was partially supported by NIGMS. R01GM128008. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 359: Pancreatic cancer cachexia is associated with infiltration of immune cells into sympathetic ganglia

Abstract The sympathetic nervous system controls the fight or flight response and regulates the physiological function of many organs. Therefore, a dysfunctional adrenergic input not only impairs normal physiology but also contributes to the ongoing pathology observed in numerous chronic conditions. This is especially true for patients suffering from cancer and cancer-associated cachexia, a multifactorial syndrome characterized by weight loss, anorexia, and increased metabolic rate. Many studies in cancer cachexia animal models demonstrated an elevated adrenergic tone, mediating white adipose tissue browning and elevating resting metabolic rate. Recent clinical studies also demonstrated signs of autonomic dysfunction in cancer cachexia patients. Indeed, treating cancer cachexia patients with beta blockers showed promising results by preventing loss of body mass, further highlighting a role for adrenergic dysfunction in driving cachexia pathophysiology. However, the mediators of adrenergic dysfunction in cancer cachexia patients remain poorly understood. To investigate this question, we used a murine model of pancreatic ductal adenocarcinoma (PDAC) associated cachexia and performed bulk RNA-sequencing of stellate ganglia (SG) (n=6) and celiac-superior mesenteric ganglia (CG-SMG) (n=6). The SG provide sympathetic innervation to the heart and brown adipose tissue, which both undergo atrophy in cancer cachexia patients. The CG-SMG provide sympathetic innervation to the liver, one of the major metabolic organs that goes awry during cachexia, along with the pancreas and the tumor. By analyzing these ganglia, we aimed to determine the molecular basis for sympathetic hyperactivity in cancer cachexia. Gene ontology analysis of our RNA-seq data revealed an enrichment of pathways associated with leukocyte migration and activation as well as regulation of inflammatory pathways (p-value < 0.0001). We complemented our RNA-seq studies with immunohistochemistry experiments of SG and CG-SMG and discovered a significant recruitment of CD45+ immune cells (Sham average: 100.6, PDAC average: 599.8; p-value < 0.001). These immune cells alter the inflammatory milieu within sympathetic ganglia, thereby providing a mechanism for dysfunctional adrenergic outflow. Considering prior studies highlighted the interaction between immune cells and sympathetic outflow in models of obesity, hypertension, and heart failure, we believe our observations point to a possible mechanism for autonomic dysfunction in cancer cachexia patients. Citation Format: Parham Diba, Mason A. Norgard, Xinxia Zhu, Tetiana Korzun, Peter R. Levasseur, Daniel L. Marks. Pancreatic cancer cachexia is associated with infiltration of immune cells into sympathetic ganglia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 359.

Optogenetic stimulation of cholinergic neuronal endings in the celiac‐superior mesenteric ganglion complex suppresses inflammation in murine endotoxemia

The vagus nerve plays a key role in the regulation of inflammation within the inflammatory reflex (Annu Rev Immunol, 2018, 36:783). In this major physiological neuroimmunoregulatory mechanism, efferent vagus nerve cholinergic axons interact with catecholaminergic neurons of the splenic nerve in the celiac‐superior mesenteric ganglion (CSMG) complex(Proc Natl Acad Sci USA, 2020, 117(47):29803).Previous studies utilizing electrical and optogenetic neuromodulation have demonstrated that vagus nerve cholinergic signalling suppresses pro‐inflammatory cytokine levels during endotoxemia and other inflammatory conditions. However, the specific role of cholinergic axonal terminals in the CSMG complex in this regulation remained enigmatic. To provide insight, we investigated the effect of selective optogenetic stimulation of cholinergic neuronal endings in the CSMG complex on cytokine and chemokine levels during murine endotoxemia. We used transgenic female 10–14‐week‐old mice expressing channelrhodopsin 2 coupled with yellow fluorescent protein on cholinergic, i.e., choline acetyltransferase positive neurons (ChAT‐ChR2‐eYFP). Anesthetized mice were subjected to abdominal surgery and the CSMG complex was localized medial to the upper pole left kidney and along the branch of the abdominal aorta, above the left renal vein. Blue laser light stimulation at 473nm was delivered in square pulses for 10mins at 20Hz, 25% duty cycle through an optic fiber cannula placed in contact with the CSMG complex. 30mins following optogenetic stimulation or sham stimulation, lipopolysaccharide (0.25mg/kg) was injected intraperitoneally and 90mins later mice were euthanized and blood, and spleen were collected and processed for cytokine and chemokines. Optogenetic stimulation of the CSMG complex in ChAT‐ChR2 mice (n=14) suppressed serum pro‐inflammatory cytokines and chemokines compared with sham stimulation (n=13), including TNF(401.7 ± 102.9 pg/ml vs 766.1 ± 207.2 pg/ml; P<0.0001) and MIP‐1α (6,523 ± 3,041 pg/ml vs 10,672 ± 3,915 pg/ml, P=0.0066), while the serum levels of the anti‐inflammatory cytokine IL‐10 were significantly increased (30,779 ± 10,035 pg/ml vs 22,979 ± 9,669 pg/ml, P=0.0427). There was also a significant reduction in splenic TNF levels in the stimulated vs the sham group(P=0.0023). Of note, optogenetic stimulation of the CSMG complex in littermate mice that do not express ChR2 on cholinergic neurons did not alter serum and splenic cytokine levels. These results provide the first experimental evidence that selective stimulation of cholinergic neuronal endings in the CSMG complex attenuates cytokine and chemokine levels. Future studies examining the specific contribution of vagal and sympathetic preganglionic cholinergic neurons in the CSMG complex in the regulation of immune responses will be instrumental for developing new targeted therapeutic anti‐inflammatory approaches.

Stimulation of hypothalamic oxytocin neurons suppresses colorectal cancer progression in mice.

Emerging evidence suggests that the nervous system is involved in tumor development in the periphery, however, the role of the central nervous system remains largely unknown. Here, by combining genetic, chemogenetic, pharmacological, and electrophysiological approaches, we show that hypothalamic oxytocin (Oxt)-producing neurons modulate colitis-associated cancer (CAC) progression in mice. Depletion or activation of Oxt neurons could augment or suppress CAC progression. Importantly, brain treatment with celastrol, a pentacyclic triterpenoid, excites Oxt neurons and inhibits CAC progression, and this anti-tumor effect was significantly attenuated in Oxt neuron-lesioned mice. Furthermore, brain treatment with celastrol suppresses sympathetic neuronal activity in the celiac-superior mesenteric ganglion (CG-SMG), and activation of β2 adrenergic receptor abolishes the anti-tumor effect of Oxt neuron activation or centrally administered celastrol. Taken together, these findings demonstrate that hypothalamic Oxt neurons regulate CAC progression by modulating the neuronal activity in the CG-SMG. Stimulation of Oxt neurons using chemicals, for example, celastrol, might be a novel strategy for colorectal cancer treatment.

Identification of a brainstem locus that inhibits tumor necrosis factor

In the brain, compact clusters of neuron cell bodies, termed nuclei, are essential for maintaining parameters of host physiology within a narrow range optimal for health. Neurons residing in the brainstem dorsal motor nucleus (DMN) project in the vagus nerve to communicate with the lungs, liver, gastrointestinal tract, and other organs. Vagus nerve-mediated reflexes also control immune system responses to infection and injury by inhibiting the production of tumor necrosis factor (TNF) and other cytokines in the spleen, although the function of DMN neurons in regulating TNF release is not known. Here, optogenetics and functional mapping reveal cholinergic neurons in the DMN, which project to the celiac-superior mesenteric ganglia, significantly increase splenic nerve activity and inhibit TNF production. Efferent vagus nerve fibers terminating in the celiac-superior mesenteric ganglia form varicose-like structures surrounding individual nerve cell bodies innervating the spleen. Selective optogenetic activation of DMN cholinergic neurons or electrical activation of the cervical vagus nerve evokes action potentials in the splenic nerve. Pharmacological blockade and surgical transection of the vagus nerve inhibit vagus nerve-evoked splenic nerve responses. These results indicate that cholinergic neurons residing in the brainstem DMN control TNF production, revealing a role for brainstem coordination of immunity.

In Adult Rats With Polycystic Ovarian Syndrome, Unilateral or Bilateral Vagotomy Modifies the Noradrenergic Concentration in the Ovaries and the Celiac Superior Mesenteric Ganglia in Different Ways.

In rats with polycystic ovarian syndrome (PCOS) induced by estradiol valerate (EV) injection, sectioning of the vagus nerve in the juvenile stage restores ovulatory function, suggesting that the vagus nerve stimulates the onset and development of PCOS. We analyzed whether in adult rats, the role played by the vagus nerve in PCOS development is associated with the nerve’s regulation of noradrenergic activity in the celiac superior mesenteric ganglion (CSMG). Ten-day-old rats were injected with corn oil [vehicle (Vh)] or EV (2 mg). At 76 days of age, rats injected with Vh or EV were subjected to sham surgery or the sectioning of one or both vagus nerves (vagotomy). The animals were sacrificed at 80–82 days of age at vaginal estrus smear. Compared to Vh-treated animals, EV-induced PCOS rats showed a lack of ovulation, the presence of follicular cysts, and a high concentration of testosterone, without changes in noradrenaline concentrations in the CSMG or ovaries. In PCOS rats, sham surgery lowered serum testosterone and noradrenaline concentrations in the CSMG but did not restore ovulation. In animals with PCOS, vagotomy lowered testosterone concentrations to a larger degree than in sham-surgery animals. The ovaries of rats with PCOS and vagotomy showed fresh corpora lutea, indicating ovulation. In EV-treated rats with unilateral vagotomy, the concentration of noradrenaline in the CSMG was similar to that in rats with PCOS and sham surgery, which did not ovulate, while in the ovaries of PCOS rats with left or bilateral vagotomy, the noradrenaline concentration was lower than that in sham-surgery-treated animals. Our results suggest that the vagus nerve regulates PCOS development through a different mechanism than the increase in the noradrenergic activity in the CSMG; however, in ovaries, the restoration of ovulation is associated with a decrease in ovarian noradrenaline.

The expression of androgen receptor in neurons of the anterior pelvic ganglion and celiac-superior mesenteric ganglion in the male pig.

The present study investigated the expression of androgen receptor (AR) in neurons of the anterior pelvic ganglion (APG) and celiac-superior mesenteric ganglion (CSMG; ganglion not involved in the innervation of reproductive organs) in the male pig with quantitative real-time PCR (qPCR) and immunohistochemistry. qPCR investigations revealed that the level of AR gene expression in the APG tissue was approximately 2.5 times higher in the adult (180-day-old) than in the juvenile (7-day-old) boars. Furthermore, in both the adult and juvenile animals it was sig- nificantly higher in the APG than in CSMG tissue (42 and 85 times higher, respectively). Immu- nofluorescence results fully confirmed those obtained with qPCR. In the adult boars, nearly all adrenergic (DβH-positive) and the majority of non-adrenergic neurons in APG stained for AR. In the juvenile animals, about half of the adrenergic and non-adrenergic neurons were AR-posi- tive. In both the adult and juvenile animals, only solitary CSMG neurons stained for AR. The present results suggest that in the male pig, pelvic neurons should be considered as an element of highly testosterone-dependent autonomic circuits involved in the regulation of urogenital func- tion, and that their sensitization to androgens is a dynamic process, increasing during the prepu- bertal period.

Changes in the tissue concentrations of several neuropeptides in porcine intestines and intestine-innervating ganglia in the course of porcine proliferative enteropathy

Inflammatory processes are associated with changes in the interplay of different pro- and anti-inflammatory factors, including neuropeptides, in tissue. This study was performed to investigate the influence of proliferative enteropathy on the concentration of several neuropeptides known to be involved in the regulation of the inflammatory process in porcine intestine and intestine-innervating ganglia. The concentration of galanin, vasoactive intestinal polypeptide, somatostatin, neuropeptide Y, substance P and calcitonin gene-related peptide were assayed with ELISA in the coeliac-superior mesenteric ganglion, inferior mesenteric ganglion, selected dorsal root ganglia, ileum and the descending colon in healthy and sick pigs. The concentrations of the studied neuropeptides were higher in sick animals. Statistically significant differences were found for coeliac-superior mesenteric ganglion (galanin, vasoactive intestinal polypeptide, somatostatin and neuropeptide Y), inferior mesenteric ganglion (galanin, somatostatin and neuropeptide Y), dorsal root ganglia (galanin, somatostatin, neuropeptide Y and calcitonin gene-related peptide), ileum (galanin and somatostatin) and the descending colon (galanin, somatostatin and neuropeptide Y). The data clearly show the influence of the inflammatory process on the concentration of some of the studied neuropeptides present in inflamed tissues and ganglia innervating the inflamed gut. These changes must be associated with the role the studied neuropeptides play in the inflammatory process.

Changes in Somatostatin-Like Immunoreactivity in the Sympathetic Neurons Projecting to the Prepyloric Area of the Porcine Stomach Induced by Selected Pathological Conditions.

The aim of the present study was to define changes in the expression of somatostatin (SOM) in the sympathetic perikarya innervating the porcine stomach prepyloric area during acetylsalicylic-acid-induced gastritis (ASA) and experimentally induced hyperacidity (HCL) and following partial stomach resection (RES). On day 1, the stomachs were injected with neuronal retrograde tracer Fast Blue (FB). Animals in the ASA group were given acetylsalicylic acid orally for 21 days. On the 22nd day after FB injection, partial stomach resection was performed in RES animals. On day 23, HCL animals were intragastrically given 5 ml/kg of body weight of a 0.25 M aqueous solution of hydrochloric acid. On day 28, all pigs were euthanized. Then, 14-μm thick cryostat sections of the coeliac-superior mesenteric ganglion (CSMG) complexes were processed for routine double-labelling immunofluorescence. All pathological conditions studied resulted in upregulation of SOM-like (SOM-LI) immunoreactivity (from 14.97 ± 1.57% in control group to 33.72 ± 4.39% in the ASA group, to 39.02 ± 3.65% in the RES group, and to 29.63 ± 0.85% in the HCL group). The present studies showed that altered expression of SOM occurs in sympathetic neurons supplying the prepyloric area of the porcine stomach during adaptation to various pathological insults.

In rats with the polycystic ovary syndrome, the monoaminergic activity in the celiac superior mesenteric ganglion depends on the vagal innervation

In rats with the polycystic ovary syndrome, the monoaminergic activity in the celiac superior mesenteric ganglion depends on the vagal innervation

Gα14 subunit-mediated inhibition of voltage-gated Ca2+ and K+ channels via neurokinin-1 receptors in rat celiac-superior mesenteric ganglion neurons

The mechanisms by which G proteins modulate voltage-gated Ca(2+)channel currents (CaV), particularly CaV2.2 and CaV2.3, are voltage dependent (VD) or voltage independent (VI). VD pathways are typically mediated by Gαi/oand GαSsubfamilies. On the other hand, VI inhibition modulation is coupled to the Gαqsubfamily and signaling pathways downstream of phospholipase C stimulation. In most studies, this latter pathway has been shown to be linked to Gαqand/or Gα11protein subunits. However, there are no studies that have examined whether natively expressed Gα14subunits (Gαqsubfamily member) couple G protein-coupled receptors (GPCR) with CaV2.2 channels. We report that Gα14subunits functionally couple the substance P (SP)/neurokinin-1 (NK-1) receptor pathway to CaV2.2 channels in acutely dissociated rat celiac-superior mesenteric ganglion (CSMG) neurons. Exposure of CSMG neurons to SP blocked the CaV2.2 currents in a predominantly VD manner that was pertussis toxin and cholera toxin resistant, as well as Gαq/11independent. However, silencing Gα14subunits significantly attenuated the SP-mediated Ca(2+)current block. In another set of experiments, exposure of CSMG neurons to SP led to the inhibition of KCNQ K(+)M-currents. The SP-mediated M-current block was significantly reduced in neurons transfected with Gα14small-interference RNA. Finally, overexpression of the GTP-bound Gαq/11binding protein RGS2 did not alter the block of M-currents by SP but significantly abolished the oxotremorine methiodide-mediated M-current inhibition. Taken together, these results provide evidence of a new Gα14-coupled signaling pathway that modulates CaV2.2 and M-currents via SP-stimulated NK-1 receptors in CSMG neurons.

Effect of selective β-adrenoceptor blockade and surgical resection of the celiac-superior mesenteric ganglion complex on delayed liquid gastric emptying induced by dipyrone, 4-aminoantipyrine, and antipyrine in rats.

There is evidence for participation of peripheral β-adrenoceptors in delayed liquid gastric emptying (GE) induced in rats by dipyrone (Dp), 4-aminoantipyrine (AA), and antipyrine (At). The present study aimed to determine whether β-adrenoceptors are involved in delayed GE induced by phenylpyrazole derivatives and the role of the prevertebral sympathetic nervous system in this condition. Male Wistar rats weighing 220-280 g were used in the study. In the first experiment rats were intravenously pretreated with vehicle (V), atenolol 30 mg/kg (ATE, β1-adrenergic antagonist), or butoxamine 25 mg/kg (BUT, β2-adrenergic antagonist). In the second experiment, rats were pretreated with V or SR59230A 2 mg/kg (SRA, β3-adrenergic antagonist). In the third experiment, rats were subjected to surgical resection of the celiac-superior mesenteric ganglion complex or to sham surgery. The groups were intravenously treated with saline (S), 240 µmol/kg Dp, AA, or At, 15 min after pretreatment with the antagonists or V and nine days after surgery. GE was determined 10 min later by measuring the percentage of gastric retention (%GR) of saline labeled with phenol red 10 min after gavage. The %GR (means±SE, n=6) values indicated that BUT abolished the effect of Dp (BUT+Dp vs V+Dp: 35.0%±5.1% vs 56.4%±2.7%) and At (BUT+At vs V+At: 33.5%±4.7% vs 52.9%±2.6%) on GE, and significantly reduced (P<0.05) the effect of AA (BUT+AA vs V+AA: 48.0%±5.0% vs 65.2%±3.8%). ATE, SRA, and sympathectomy did not modify the effects of treatments. These results suggest that β2-adrenoceptor activation occurred in delayed liquid gastric emptying induced by the phenylpyrazole derivatives dipyrone, 4-aminoantipyrine, and antipyrine. Additionally, the released neurotransmitter did not originate in the celiac-superior mesenteric ganglion complex.

Neurochemical Plasticity of the Coeliac-Superior Mesenteric Ganglion Complex Neurons Projecting to the Prepyloric Area of the Porcine Stomach following Hyperacidity

This study was designed to determine neurochemical properties of the coeliac-superior mesenteric ganglion (CSMG) neurons supplying the prepyloric area of the porcine stomach in physiological state and following experimentally induced hyperacidity. To localize sympathetic neurons innervating the studied area of stomach, the neuronal retrograde tracer Fast Blue (FB) was applied to control animals and hydrochloric acid infusion (HCl) groups. After 23 days, animals of the HCl group were reintroduced into a state of general anesthesia and intragastrically given 5 mL/kg of body weight of 0.25 M aqueous solution of hydrochloric acid. On the 28th day, all animals were sacrificed. The CSMG complexes were then collected and processed for double-labeling immunofluorescence. In the control animals, FB-positive perikarya displayed immunoreactivity to tyrosine hydroxylase (TH), dopamine β-hydroxylase (DβH), neuropeptide Y (NPY), and galanin (GAL). Experimentally induced gastric hyperacidity changed the neurochemical phenotype of the studied neurons. An upregulated expression of GAL and NPY and the de novo synthesis of neuronal nitric oxide synthase (nNOS) and leu5-enkephalin (LENK) as well as downregulated expression of TH and DβH in the stomach-projecting neurons were observed. These findings enrich existing knowledge about the participation of these active substances in adaptive mechanism(s) of the sympathetic neurons during pathological processes within the gastrointestinal tract.

Alterations of neurochemical expression of the coeliac-superior mesenteric ganglion complex (CSMG) neurons supplying the prepyloric region of the porcine stomach following partial stomach resection.

The purpose of the present study was to determine the response of the porcine coeliac-superior mesenteric ganglion complex (CSMG) neurons projecting to the prepyloric area of the porcine stomach to peripheral neuronal damage following partial stomach resection. To identify the sympathetic neurons innervating the studied area of stomach, the neuronal retrograde tracer Fast Blue (FB) was applied to control and partial stomach resection (RES) groups. On the 22nd day after FB injection, following laparotomy, the partial resection of the previously FB-injected stomach prepyloric area was performed in animals of RES group. On the 28th day, all animals were re-anaesthetized and euthanized. The CSMG complex was then collected and processed for double-labeling immunofluorescence. In control animals, retrograde-labelled perikarya were immunoreactive to tyrosine hydroxylase (TH), dopamine β-hydroxylase (DβH), neuropeptide Y (NPY) and galanin (GAL). Partial stomach resection decreased the numbers of FB-positive neurons immunopositive for TH and DβH. However, the strong increase of NPY and GAL expression, as well as de novo-synthesis of neuronal nitric oxide synthase (nNOS) and leu5-Enkephalin (LENK) was noted in studied neurons. Furthermore, FB-positive neurons in all pigs were surrounded by a network of cocaine- and amphetamine-regulated transcript peptide (CART)-, calcitonin gene-related peptide (CGRP)-, and substance P (SP)-, vasoactive intestinal peptide (VIP)-, LENK- and nNOS- immunoreactive nerve fibers. This may suggest neuroprotective contribution of these neurotransmitters in traumatic responses of sympathetic neurons to peripheral axonal damage.

Modulation of voltage-gated Ca2+ channels by G protein-coupled receptors in celiac-mesenteric ganglion neurons of septic rats.

Septic shock, the most severe complication associated with sepsis, is manifested by tissue hypoperfusion due, in part, to cardiovascular and autonomic dysfunction. In many cases, the splanchnic circulation becomes vasoplegic. The celiac-superior mesenteric ganglion (CSMG) sympathetic neurons provide the main autonomic input to these vessels. We used the cecal ligation puncture (CLP) model, which closely mimics the hemodynamic and metabolic disturbances observed in septic patients, to examine the properties and modulation of Ca2+ channels by G protein-coupled receptors in acutely dissociated rat CSMG neurons. Voltage-clamp studies 48 hr post-sepsis revealed that the Ca2+ current density in CMSG neurons from septic rats was significantly lower than those isolated from sham control rats. This reduction coincided with a significant increase in membrane surface area and a negligible increase in Ca2+ current amplitude. Possible explanations for these findings include either cell swelling or neurite outgrowth enhancement of CSMG neurons from septic rats. Additionally, a significant rightward shift of the concentration-response relationship for the norepinephrine (NE)-mediated Ca2+ current inhibition was observed in CSMG neurons from septic rats. Testing for the presence of opioid receptor subtypes in CSMG neurons, showed that mu opioid receptors were present in ~70% of CSMG, while NOP opioid receptors were found in all CSMG neurons tested. The pharmacological profile for both opioid receptor subtypes was not significantly affected by sepsis. Further, the Ca2+ current modulation by propionate, an agonist for the free fatty acid receptors GPR41 and GPR43, was not altered by sepsis. Overall, our findings suggest that CSMG function is affected by sepsis via changes in cell size and α2-adrenergic receptor-mediated Ca2+ channel modulation.

Effects of celiac superior mesenteric ganglionectomy on glucose homeostasis and hormonal changes during oral glucose tolerance testing in rats

The liver plays an important role in maintaining glucose homeostasis in the body. In the prandial state, some of the glucose which is absorbed by the gastrointestinal tract is converted into glycogen and stored in the liver. In contrast, the liver produces glucose by glycogenolysis and gluconeogenesis while fasting. Thus, the liver contributes to maintaining blood glucose level within normoglycemic range. Glycogenesis and glycogenolysis are regulated by various mechanisms including hormones, the sympathetic and parasympathetic nervous systems and the hepatic glucose content. In this study, we examined a rat model in which the celiac superior mesenteric ganglion (CSMG) was resected. We attempted to elucidate how the celiac sympathetic nervous system is involved in regulating glucose homeostasis by assessing the effects of CSMG resection on glucose excursion during an oral glucose tolerance test, and by examining hepatic glycogen content and hepatic glycogen phosphorylase (GP) activity. On the oral glucose tolerance test, CSMG-resected rats demonstrated improved glucose tolerance and significantly increased GP activity compared with sham-operated rats, whereas there were no significant differences in insulin, glucagon or catecholamine levels between the 2 groups. These results suggest that the celiac sympathetic nervous system is involved in regulating the rate of glycogen consumption through GP activity. In conclusion, the examined rat model showed that the celiac sympathetic nervous system regulates hepatic glucose metabolism in conjunction with vagal nerve innervations and is a critical component in the maintenance of blood glucose homeostasis.

Sympathetic Activity Controls Fat-Induced Oleoylethanolamide Signaling in Small Intestine

Ingestion of dietary fat stimulates production of the small-intestinal satiety factors oleoylethanolamide (OEA) and N-palmitoyl-phosphatidylethanolamine (NPPE), which reduce food intake through a combination of local (OEA) and systemic (NPPE) actions. Previous studies have shown that sympathetic innervation of the gut is necessary for duodenal infusions of fat to induce satiety, suggesting that sympathetic activity may engage small-intestinal satiety signals such as OEA and NPPE. In the present study, we show that surgical resection of the sympathetic celiac-superior mesenteric ganglion complex, which sends projections to the upper gut, abolishes feeding-induced OEA production in rat small-intestinal cells. These effects are accounted for by suppression of OEA biosynthesis, and are mimicked by administration of the selective β2-adrenergic receptor antagonist ICI-118,551. We further show that sympathetic ganglionectomy or pharmacological blockade of β2-adrenergic receptors prevents NPPE release into the circulation. In addition, sympathetic ganglionectomy increases meal frequency and lowers satiety ratio, and these effects are corrected by pharmacological administration of OEA. The results suggest that sympathetic activity controls fat-induced satiety by enabling the coordinated production of local (OEA) and systemic (NPPE) satiety signals in the small intestine.

Lateralization of the connections of the ovary to the celiac ganglia in juvenile rats

During the development of the female rat, a maturing process of the factors that regulate the functioning of the ovaries takes place, resulting in different responses according to the age of the animal. Studies show that peripheral innervation is one relevant factor involved.In the present study we analyzed the anatomical relationship between the neurons in the celiac-superior mesenteric ganglia (CSMG), and the right or left ovary in 24 or 28 days old female pre-pubertal rats. The participation of the superior ovarian nerve (SON) in the communication between the CSMG and the ovaries was analyzed in animals with unilateral section of the SON, previous to injecting true blue (TB) into the ovarian bursa. The animals were killed seven days after treatment. TB stained neurons were quantified at the superior mesenteric-celiac ganglia.The number of labeled neurons in the CSMG of rats treated at 28 days of age was significantly higher than those treated on day 24. At age 24 days, injecting TB into the right ovary resulted in neuron stains on both sides of the celiac ganglia; whereas, injecting the left side the stains were exclusively ipsilateral. Such asymmetry was not observed when the rats were treated at age of 28 days.In younger rats, sectioning the left SON resulted in significantly lower number of stained neurons in the left ganglia while sectioning the right SON did not modify the number of stained neurons. When sectioning of the SON was performed to 28 days old rats, no staining was observed.Present results show that the number and connectivity of post-ganglionic neurons of the CSMG connected to the ovary of juvenile female rats change as the animal mature; that the SON plays a role in this communication process as puberty approaches; and that this maturing process is different for the right or the left ovary.

Vagal and splanchnic afferent nerves are not essential for anorexia associated with abomasal parasitism in sheep

Heavy burdens of the abomasal nematode, Ostertagia ( Telodorsagia) circumcincta, in growing lambs result in a reduction in liveweight gain due largely to a drop in voluntary feed intake. The present study investigated: (1) the role of subdiaphragmatic vagal and non-vagal visceral afferent nerves in mediating a reduction in voluntary feed intake, using subdiaphragmatic vagal deafferentation (vagotomy) either alone or in combination with coeliac-superior mesenteric ganglionectomy (vagotomy and sympathectomy); and (2) the association between appetite, abomasal pH, selected blood values (amidated gastrin (G-17-amide), glycine-extended gastrin (G-17-Gly), pepsinogen and leptin) and worm burden, in sheep experimentally infected with 100 000 O. circumcincta infective larvae per os. Neither vagotomy alone nor vagotomy and sympathectomy in combination adversely affected the establishment or course of development of the parasite burden, when compared with a control group subject to sham surgery. Furthermore, neither surgical procedure prevented the drop in appetite seen 5–10 days post-infection, although combined vagotomy and sympathectomy did reduce voluntary feed intake prior to the start of the study. Ostertagia infection resulted in a significant increase in abomasal pH in all three groups, which was accompanied by an increase in blood G-17-amide and in G-17-Gly, the latter reported for the first time in parasitized ruminants. There were no significant differences in blood leptin, also reported for the first time in parasitized sheep, either between groups or in comparison with pre-infection levels, though weak negative correlations were established between blood leptin and appetite from day 5 to the end of the study in all three groups and a positive correlation with blood G-17-amide in the control group over the same period. These data suggest that neither intact subdiaphragmatic vagal afferent nerves or coeliac-superior mesenteric ganglion fibres, nor changes in circulating gastrin and leptin concentrations play a major role in mediating the hypophagic effects of O. circumcincta in parasitized sheep.