bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relief of endoplasmic reticulum stress in the brain subfornical organ rescues high fat diet‐induced non‐alcoholic fatty liver disease (1126.16)
Authors: Horwath Julie , Young Colin , Butler Scott , Mark Allyn , Davisson Robin 
Published: June 2021

NAFLD is a hallmark of metabolic syndrome and endoplasmic reticulum (ER) stress has been suggested as an underlying mechanism. However, the role of the brain in mediating NAFLD remains unclear. Importantly, brain ER stress has emerged as the basis of a number of chronic diseases, and we have recently demonstrated robust ER stress in the subfornical organ (SFO) of high fat diet (HFD)‐fed mice. Therefore, we tested the hypothesis that ER stress in the SFO mediates HFD‐induced NAFLD. Male C57Bl/6 mice were fed HFD (60% fat, n=13) for 20 weeks. SFO‐targeted microinjections of an adenovirus encoding the ER chaperone GRP78 (AdGRP78) to reduce ER stress, or control vector (AdLacZ), were then performed. Selective reductions in SFO‐ER stress resulted in a significant decrease in HFD‐induced hepatomegaly (2.25±0.06 vs 1.71±0.12 g, HFD AdLacZ vs HFD AdGRP78, p<0.05), with no changes in body weight (49±1 vs 48±2 g, HFD AdLacZ vs HFD AdGRP78, p>0.05), food intake or adiposity. SFO‐targeted AdGRP78 also reduced HFD‐mediated lipid droplet accumulation in the liver (histological examination) and hepatic triglyceride accumulation (203±22 vs. 96±16 mmol; HFD AdLacZ vs. HFD AdGRP78; p<0.05). These findings demonstrate a novel role for brain SFO ER stress as a contributor to the NAFLD, independent of an influence on body weight, food intake and adiposity.Grant Funding Source: Supported by HL63887, HL84207, AHA13POST14410020, K99HL166776
WFS1‐deficient mice have alterations in energy metabolism: role of TRPM8 receptors (1126.17)
Authors: Koks Sulev , Ivask Marilin , Ehrlich Marite 
Published: June 2021

Wolfram syndrome, an autosomal recessive disorder characterized by juvenile‐onset diabetes mellitus and optic atrophy, is caused by mutations in the wolframin (Wfs1) gene. Wfs1 negatively regulates endoplasmic reticulum (ER) stress signalling and therefore have a role in the pathogenesis of diabetes and regulation of metabolism. One cardinal feature of Wfs1 mutant mice is their significantly reduced body weight. The real mechanism of weight loss is not known, but these mice develop normally until the age of 8 weeks. After this period weight loss starts. We recently found significant up‐regulation of TRPM8 gene in the hippocampus of Wfs1 mutant mice. TRPM8 is menthol receptor and is involved in the regulation of energy metabolism. In present study we analysed metabolic activity and sensitivity of Wfs1 mutant mice to the menthol stimulation. We found that Wfs1 mutant mice have elevated metabolic activity in metabolic cages. Moreover, menthol induced significant increase in basal metabolic activity in Wfs1 mutant mice. Over‐activation of TRPM8 receptor can explain increased metabolic rate in Wfs1 mutant mice and their reduced body weight.Grant Funding Source: Supported by The European Regional Development Fund
Neuro‐glio‐vascular dysfunction and epigenetic remodeling in diabetic stroke (1126.19)
Authors: Kalani Anuradha , Kamat Pardip , Tyagi Suresh , Metreveli Naira , Tyagi Neetu 
Published: June 2021

Clinical studies demonstrate that stroke in diabetes leads to exacerbated brain damage and functional decline but the nature and mechanisms are still undefined. Therefore, we hypothesize that stroke in diabetes severely disturbed neuro‐glio‐vascular unit and cognitive functions instigated by epigenetic remodeling. To test this hypothesis, we employed 8‐10 week‐old male C57BL/6J (WT) sham, WT+ ischemia reperfusion (I/R), Akita (Ins2+/‐, diabetic) sham, and Akita+I/R, mice groups. Ischemia was performed for 60 min and reperfusion for 24 h. Infarct area and edema were measured with 2,3,5‐triphenyltetrazolium chloride and Evans blue extravasation, respectively. We found that infarct area, edema, and brain functions (memory, hearing) are severely affected in Akita I/R as compared to I/R group. DNMTs and HDACs activity/expressions were highly altered in Akita I/R, as compared to I/R and sham operated groups, signifies epigenetic alterations. Molecular assessments exemplified Akita I/R severity, as compared to IR group, in terms of increase in white matter damage (amyloid beta), matrix metalloproteinase (MMP‐9), glutamatergic response (NMDA), and permeability of blood vessels. On contrary, Akita I/R exhibited decrease in neural differentiation (netrin‐1, nestin) and tight junctions (ZO‐1, claudin‐5) protein/transcript expressions as compared to I/R and sham operated groups. Immunohistochemistry studies determined deep alterations of vascular connections (Cx45, CD31, GFAP) and ion channels (Na+‐K+, Ca++) in Akita I/R as compared to I/R group. These results suggest stroke severity in diabetic brain due to intense damage in neuro‐glio‐vascular unit with epigenetic remodeling and stipulate treatments much needed to be explored.Grant Funding Source: HL107640
Glucose responsive neurons in the nucleus of the solitary tract are responsive to nesfatin‐1 (1126.3)
Authors: Mimee Andrea , Ferguson Alastair 
Published: June 2021

Nesfatin‐1 (nes‐1) exerts important effects on food intake and glucose handling and is expressed in the nucleus of the solitary tract (NTS), a critical medullary autonomic control center. Since hypoglycemia induces cFos expression in nes‐1 immunoreactive NTS neurons, here we examined effects of nes‐1 on the excitability of glucose responsive NTS cells using whole‐cell patch clamp recordings. A total of 44% of neurons tested (7/16) responded to a decrease from 3 to 0.2 mM glucose, 4 with a depolarization (glucose inhibited (GI), mean 6.1 ± 1.6 mV), and 3 with a hyperpolarization (glucose excited (GE), mean ‐5.7 ± 1.4 mV). Bath applied nes‐1 (10 nM) influenced the excitability of all but one of these glucose responsive neurons. All GI neurons responded to nes‐1, 3 with a depolarization (mean 7.6 ± 2.4 mV) and 1 with a hyperpolarization (‐8.5 mV). Moreover, 2/3 GE cells were depolarized by nes‐1 (mean 3.3 ± 1.0 mV) while 1 did not respond. NTS neurons which did not respond to changes in glucose (9/16) were also nes‐1 responsive, with 5 showing a depolarization (mean 3.5 ± 0.4 mV) and 4 a hyperpolarization (mean ‐5.8 ± 0.5 mV). While our findings reveal clear actions of nes‐1 on glucose sensing NTS neurons, they do not suggest functional differentiation between the effects of nes‐1 on GI and GE neurons. Our observations lend further support to the hypothesis that nes‐1 may act as a locally released modulator of intrinsic neuronal function.Grant Funding Source: NSERC, FQRNT, HSFO
Neuropeptide Y1 receptor is a key element in stress response to food deprivation (1126.7)
Authors: Dimitrov Eugene , DeJoseph M. , Urban Janice 
Published: June 2021

The hypothalamic‐pituitary adrenal (HPA) axis functions as a default pathway for the maintenance of energy homeostasis. Food restriction or deprivation leads to prolonged HPA axis activation but the exact mechanism of this continuous HPA activation is not yet well understood. Our experiments were designed to determine whether neuropeptide Y (NPY) Y1 receptors participate in the stress response to food deprivation since NPY expression is elevated during periods of fasting. Food deprivation of male rats for 24 hours caused weight loss, adrenal gland hypertrophy and increased plasma ACTH and corticosterone concentrations. Food deprivation increased NPY mRNA expression in arcuate and brainstem C2/A2 nuclei areas that are known to project to the hypothalamic paraventricular nucleus (PVN). While the total area of CRH mRNA positive cells in the PVN decreased during food deprivation, the CRH mRNA signal intensity increased in the remaining active cells. Food deprivation also increased pCREB‐ir expression in PVN, an indication for neuronal activation. A majority of pCREB‐positive cells were CRH/Y1‐ir neurons. Infusion into the PVN of 1 nmol BIBP3226, a specific Y1 receptor antagonist, eliminated the elevated corticosterone blood levels in food‐deprived animals. Our observations support the notion that hypothalamic NPY Y1 receptors expressed by CRH neurons are pivotal for triggering a strong stress response during periods of food deprivation.Grant Funding Source: Supported by NIMH 62621
Evidence of decreased dopamine receptor‐mediated control of gap junction coupling in the inner nuclear layer of the diabetic Ins2Akita mouse retina (1129.1)
Authors: Fortepiani Lourdes , Pyarali Monika , Akimov Nikolay , Zhang Zhijing , Ribelayga Christophe , Rentería René 
Published: June 2021

Dopamine (DA) is a light‐adaptive factor that plays an important role in daytime vision. DA controls the gain of retinal signal transmission partly by controlling gap junction coupling of retinal neurons. Because preliminary data suggests that DA levels are lower in the diabetic Ins2Akita mouse retina, we hypothesized that gap junction coupling would be altered in diabetic retina. We assayed coupling using a “cut‐loading” technique, in which whole‐mounted retinas are cut with a razor dipped in gap junction‐permeable tracer Neurobiotin (NB) and quantified NB‐labeled cells in the inner nuclear layer (INL) using fluorescence microscopy. Experiments were performed under dark‐adapted conditions. The extent of coupling in control (C57Bl6) retinas was tested in the presence of the D2‐like receptor (D2R) agonist quinpirole, the D2R antagonist sulpiride, or the gap junction antagonist beta‐glycyrrhizic acid (BGA). As expected, D2R activation and BGA reduced gap junction coupling of the NB‐labeled cells in the INL, while D2R antagonism increased tracer coupling. In the diabetic Ins2Akita mice, we found that neurons in the INL showed increased tracer coupling compared to non‐diabetic littermates. We propose that this increase in gap junction coupling between retinal neurons reflects a decrease in DA levels. Decreased DA levels and an altered coupling state of retinal neurons may be hallmarks of diabetic retinasGrant Funding Source: Supported by American Heart Association (12BGIA12040362)
Expression of NaV1.9 channels by muscle afferent neurons (1129.10)
Authors: Marler Tyler , Elmslie Keith 
Published: June 2021

Background: The exercise pressor reflex helps regulate cardiovascular responses to exercise. The voltage‐gated sodium channel (Nav) 1.9 has unique properties that could help to generate excessive neuronal activity. We have previously demonstrated the presence of Nav1.9 channels using antibody staining of identified neurons, but were not able to demonstrate functional activity (J Neurophysiol. 108: 2230, 2012). Methods: We voltage‐clamped identified muscle afferent neurons isolated from adult male Sprague Dawley rats and used a high fluoride internal solution to help separate Nav1.9 from Nav1.8. Results: We found a Nav1.9‐like current that activated at voltages 20 mV hyperpolarized to the main Nav1.8 current in 69% of muscle afferent neurons (n=13). This current exhibited significantly slower activation (8 ± 3 ms; n=9) compared with cells that showed only Nav1.8 (4 ± 1 ms; n=4). The Nav current in cells with Nav1.9‐like current inactivated with multiple components compared with a single component inactivation of neurons that showed only Nav1.8. Unexpectedly, the size of the Nav1.9 current declined (ran down) with time during whole‐cell recording, while the Nav1.8 current level appeared to be invariant with time. The current density of the Nav1.9‐like current declined 43% ± 35% (mean ± SD, n=5) over approximately 5 min. We are investigating the role of dialyzable molecules such as ATP in the maintenance of Nav1.9 current. Conclusion: Nav1.9 channels are functionally expressed in muscle afferent neurons. The kinetic properties of Nav1.9 (e.g. slow inactivation) could make this channel an important regulator of muscle afferent activity to exacerbate the exercise pressor reflex.Grant Funding Source: NIH grant AR059397 (KSE) and ATSU BMS grant (TLM)
Calcium signaling and neuropeptide secretion in the expulsion step of the Caenorhabditis elegans defecation motor program (1129.6)
Authors: McCright Sam , Peters Maureen 
Published: June 2021

A periodic posterior to anterior intestinal calcium wave initiates the defecation motor program of Caenorhabditis elegans (C. elegans). innexin‐16 (inx‐16) encodes an intestinal pannexin gap junction subunit. inx‐16 mutants have faulty calcium waves and mostly lack the expulsion step of the motor program. Our work investigates how these defective calcium waves result in loss of expulsion. The anterior‐ventral neuron L (AVL) and dorsal‐ventral neuron B (DVB) are responsible for expulsion through a two‐step signaling process. An intestinal neuropeptide‐like protein, NLP‐40, activates AVL and DVB which in turn release neurotransmitters to stimulate expulsion. NLP‐40 release likely depends on intestinal calcium flux, as vesicular localization of NLP‐40 requires synaptotagmin‐2.We propose that the expulsion defects in the inx‐16 mutant are due to improper NLP‐40 release. To establish if inx‐16’s AVL and DVB neurons are functional, we used optogenetic methods. Activation of a light‐gated ion channel channelrhodopsin‐2 (ChR2) in AVL and DVB of inx‐16 animals resulted in normal expulsion 90% of the time. This demonstrates that an inx‐16 animal’s AVL and DVB neurons are able to signal expulsion and supports our hypothesis that defects in inx‐16’s intestinal NLP‐40 release inhibit expulsion. Current work addresses whether NLP‐40 is properly synthesized and released.
Effects of pregabalin on D‐serine content and NMDA receptor‐mediated synaptic transmission in the mouse spinal cord (1129.9)
Authors: Matsuzawa Rie , Takasusuki Toshifumi , Maekawa Masao , Yamaguchi Shigaki , Hori Yuuichi 
Published: June 2021

The anticonvulsant pregabalin (PGB) is used to relieve neuropathic pain. It has been shown that PGB binds to presynaptic calcium channels and subsequently inhibits transmitter release. Additionally, a preponderance of the evidence raises the possibility of other mechanisms independent of binding to calcium channels. In the present experiments, we have studied the effects of PGB on D‐serine content and NMDA receptor‐mediated synaptic transmission in the spinal cord dorsal horn.Experiments were performed on adult ICR mice. The sciatic nerve was partially ligated under halothane anesthesia. Mechanical allodynia was assessed by von Frey filaments. PGB (30‐50 mg/kg body weight) was intraperitonealy injected daily for 5‐7 days. The lumbar spinal cord was removed, homogenized, and ultrafiltrated. Supernatant samples were treated with Marfey's reagent and analyzed with liquid chromatography‐mass spectrometry for D‐serine concentration. Tight‐seal whole‐cell recordings were made from neurons in the superficial dorsal horn of spinal cord slices. Excitatory postsynaptic currents (EPSCs) were evoked by electrical stimulation.D‐serine content was 9.9±1.0 nM/g of wet tissue in sciatic nerve‐ligated mice (n=6), which was significantly larger than that in sham‐operated mice (7.9±0.8 nM/g, p < 0.05). PGB considerably decreased D‐serine content to 6.0±0.9 nM/g (n=6, p < 0.05, vs. sciatic nerve‐ligated mice). PGB decreased the NMDA/non‐NMDA ratio of the EPSC amplitude, and shortened the decay phase of the NMDA component of the EPSCs. These observations suggest that PGB decreases D‐serine concentration and thereby affects synaptic plasticity.Grant Funding Source: Supported by a grant from the Japan Society for the Promotion of Science (23500468 to Y.H.).
Renal denervation attenuates the enhanced activation of the paraventricular nucleus in heart failure: restoring nNOS! (1130.10)
Authors: Patel Kaushik , Liu Xuefei , Llewellyn Tamra , Zheng Hong 
Published: June 2021

Previously we have shown that activated paraventricular nucleus (PVN) contributes to the sympatho‐excitation in chronic heart failure (HF). Afferent renal nerves project to neurons in several brain areas, including the PVN, that are involved in the regulation of the cardiovascular system. The purpose of the present study was to determine if the activation of the PVN was mediated by afferent renal nerves. Chronic HF was induced by left coronary ligation surgery for 3‐4 weeks and rats were surgically renal denervated (RDN) for 2 weeks. RDN resulted in reduced levels of urinary norepinephrine excretion in rats with HF compared with sham‐operated control rats. RDN resulted in reduced levels of FosB staining in the PVN in rats with HF. RDN also resulted in restoration of nNOS levels (NOS histochemistry and nNOS immunostaining) in the PVN of rats with HF. We observed that microinjections of L‐NMMA (NOS inhibitor) into the PVN induced a significant smaller increase in lumbar sympathetic nerve activity in anaesthetized rats with HF compared with sham rats. In contrast, RDN restored the L‐NMMA responses in rats with HF. These results suggest that intact renal nerves contribute to the reduction of nNOS within the PVN resulting in activation of the neurons in the PVN of rats with HF. RDN restores nNOS within the PVN and thus attenuates the enhanced neuronal activation as well as the sympatho‐excitation commonly observed in HF. Supported by NIH grant HL62222 &amp; DK82956.Grant Funding Source: NIH grant HL62222 & DK82956.
Neuronal plasticity within the medullary dorsal horn: the nasopharyngeal response returns 3 days after bilateral sectioning of the anterior ethmoidal nerve (1130.19)
Authors: McCulloch Paul , DiNovo Karyn 
Published: June 2021

Stimulation of the nasal passages with ammonia vapors can reflexly produce bradycardia, apnea, and increased peripheral resistance. However, after acute bilateral sectioning of the anterior ethmoidal nerve (AEN), the nerve that innervates the nasal passages, this nasopharyngeal response consists of only a slight apnea and an increase in arterial pressure. In the present experiments, in urethane‐anesthetized Sprague‐Dawley rats, we recorded the cardiorespiratory responses to ammonia vapor stimulation of the nasal passages 3, 5, 7 and 9 days after bilateral sectioning of the AEN, and compared these responses to those from rats with sham and acute (0 day) AEN sectioning. After nasal stimulation, heart rate (HR) decreased 62% in Sham rats but only 12% in Acute rats. After waiting 3 days following AEN sectioning, HR decreased 26%, and when waiting 9 days by 32%. The re‐establishment of the cardiorespiratory responses to nasal stimulation after bilateral AEN sectioning suggests that other nerves that innervate the nasal passages are able to provide an afferent signal sufficient to initiate the nasopharyngeal reflex. Additionally, because the bradycardia is strongly attenuated after acute AEN sectioning, our research suggests that neuronal plasticity within the medullary dorsal horn, the brainstem termination site of the AEN, may be necessary before the re‐establishment of the nasopharyngeal response can occur.Grant Funding Source: Supported by MWU Office of Research and Sponsored Programs.
Monoamine innervation of vagal motor neurons retrogradely labelled from the subdiaphragmatic oesophagus (1131.3)
Authors: Llewellyn‐Smith Ida , Travis Lee , Watson David , Dinning Phil , Spencer Nick , Fong Angelina , Menuet Clement , Allen Andrew 
Published: June 2021

Neurons in the dorsal motor nucleus of the vagus (DMV) and nucleus ambiguus pars compacta (NAc) innervate the subdiaphragmatic oesophagus in rodents but little is known about the central circuitry that controls the activity of these vagal motor neurons. We assessed the monoamine innervation of these two groups of esophageal motor neurons with immunohistochemistry, conventional retrograde tracing and anterograde tracing using lentiviral vectors that drive GFP expression in either catecholamine or 5‐HT neurons. Close appositions from axons immunoreactive for 5‐HT or catecholamine synthetic enzymes (tyrosine hydroxylase or phenylethanolamine N‐methyltransferase) occurred on many esophageal motor neurons in DMV that had been retrogradely labelled with cholera toxin B subunit (CTB) from the oesophagus. In contrast, all three types of axons very rarely apposed CTB‐labelled motor neurons in NAc. In rats with lentiviral‐induced selective GFP expression in C1, C3 or midline 5‐HT neurons, GFP‐immunoreactive axons were found in close apposition to choline acetyltransferase (ChAT)‐positive DMV neurons, but not ChAT‐positive NAc neurons. This marked difference in innervation indicates that monoamine axons of brainstem origin are likely to be important for controlling the activity of esophageal motor neurons in DMV but not those in NAc. This conclusion is consistent with control of oesophageal smooth muscle by DMV neurons and of oesophageal striated muscle by NAc neurons.Grant Funding Source: NHMRC of Australia
Sensory re‐innervation of the rat uterus postpartum (1131.4)
Authors: Llewellyn‐Smith Ida , Gnanamanickam Greta 
Published: June 2021

Sympathetic, parasympathetic and sensory nerves almost completely disappear from the pregnant rat uterus at term but return of nerves post‐partum is not well characterized. Using immunoperoxidase staining for calcitonin gene related peptide (CGRP), we assessed post‐partum (P) sensory re‐innervation of rat uterus in whole mount preparations from days P1, P3, P5, P7, P10 and P14 (n=4/group). At P1, there were few CGRP‐immunoreactive axons, mostly at the mesometrium, where a few blood vessels were lightly innervated. CGRP‐positive axons increased at P3 and P5. There were many growth cones at both times. Muscle innervation was sparse. At P7, innervation was denser, with slightly more axons in the muscle and rare CGRP‐IR axons deep in the endometrium. There were CGRP‐immunoreactive axons in the linea uteri at the ovarian end in half the rats. At P10, the pattern of CGRP innervation was similar to P7. More CGRP‐immunoreactive axons occurred in all regions but re‐innervation of the linea uteri continued to lag behind. CGRP innervation was heaviest at P14, with blood vessels moderately to heavily innervated. Nevertheless, CGRP innervation density in all uterine layers was still much less at P14 than at oestrus. These results show that sensory innervation of the uterus has begun to return at P1. Uterine CGRP innervation increases to P14 but innervation density is still lower than in the non‐pregnant state.Grant Funding Source: Supported by NHMRC Australia
Cystitis‐induced bladder overactivity is prevented by inhibition of N‐methyl‐d‐aspartate receptor‐mediated inflammatory responses in the urinary bladder (1131.5)
Authors: Liu Miao , Shen Shanwei , Grider John , Qiao Liya 
Published: June 2021

We previously show that NMDAR‐mediated signaling pathways play a significant role in regulating spinal plasticity during cyclophosphamide (CYP) ‐induced cystitis. Here we show that administration of a specific NMDAR antagonist MK801 (3mg/kg body weight, i.v.) to cystitis rats reversed bladder overactivity and inflammation at 48 h post drug treatment. In metabolic tests, MK801‐treated cystitis group had an average of 3.3 ± 1.0 voiding per hour whereas the group treated with CYP alone showed an average of 15.1 ± 5.8 voiding per hour (n=5, p<0.05). Cystometry results show that MK801 treatment of cystitis animals had a significant longer intermicturition intervals (192.0 ± 15.9 seconds(s)) when compared to CYP treatment alone (48.8 ± 4.6s, n=3, p<0.05). MK801 treatment also decreased cystitis‐induced increases in the ratio of bladder weight to body weight (CYP: 0.73 ± 0.09 mg/g; CYP+MK801: 0.35 ± 0.02 mg/g; n=5, p<0.05), and restored the integrity of urothelium damaged by CYP treatment. The effects of MK801 on cystitis‐induced bladder inflammation was also examined by its ability in reversing the elevated expression levels of pro‐inflammatory factors interlukin (IL)‐1alpha, IL‐6 and TNFalpha in the urinary bladder during cystitis. Taken together, we show that blockade of NMDAR‐mediated pathways can be an effective regimen in treatment of cystitis‐associated bladder overactivity and inflammation.Grant Funding Source: NIH DK077917