bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combined V1a and V1b Receptor Activation Within the Paraventricular Nucleus Contributes to Sympathoexcitation and Hypertension in Rats Exposed to Chronic Mild Unpredictable Stress
Authors: Komnenov Dragana , Quaal Harrison , Rossi Noreen Felice 
Published: June 2021

The paraventricular nucleus (PVN) in the brain has been recognized as a major integrative center for neurohumoral regulation which receives a broad array of afferent inputs. As such, the function of the PVN becomes even more important in times of physical or physiological stress. Two distinct neuronal populations we are interested in include the magnocellular and parvocellular neurons. Specifically, we are interested in deciphering how intranuclearly released vasopressin (AVP) from the magnocellular neurons acts upon the parvocellular pre‐sympathetic neurons and glia that are richly endowed with V1a and V1b receptors in a rat model of depression. It has been demonstrated that V1a receptor activation depolarizes PVN pre‐sympathetic neurons and initiates an action potential, which puts forth a signaling cascade that increases sympathetic nerve activity, arterial pressure and heart rate. Additionally, we previously published that renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP) and heart rate (HR) responses to AVP microinjected in the PVN is significantly attenuated when the rats were pretreated with V1b receptor antagonist nelivaptan. In this study, we set out to identify differences in baseline RSNA, MAP and HR between rats exposed to the chronic mild unpredictable stress protocol (CMS) and their normal counterparts, as well as their responses to AVP microinjected into the PVN in the presence of the V1a receptor antagonist, Manning compound, and the V1b receptor inhibitor, nelivaptan. We observed that baseline MAP is higher in CMS rats (110 ± 2 mmHg vs. 115 ± 1 mmHg; P < 0.05). Furthermore, in control rats, combined inhibition of AVP with nelivaptan and Manning compound resulted in near complete abolition of the rise in MAP and baroreflex‐mediated decreases in HR and RSNA. CMS rats exhibited exaggerated baseline RSNA, 43.6 ± 9.97 μV.ms compared with control rats, 8.04 ± 3.24 μV.ms (P < 0.025). PVN AVP injection increased RSNA by 52.1 ± 3.3 %baseline in controls and was blocked by the dual blockade. RSNA did not increase significantly after PVN AVP in CMS rats and V1a receptor and V1b receptor blockade did not change this response. CMS rats displayed higher baseline RSNA 43.6 ± 9.9 μV.ms vs control rats 8.0 ± 3.9 μV.ms P < 0.025). Moreover, dual blockade significantly decreased RSNA from baseline values only in CMS rats: −12.6 ± 0.4 μV.ms compared with control rats −1.1 ± 0.6 μV.ms (P < 0.05). These findings are consistent with the concept that arterial pressure and RSNA are increased during chronic stress via dendritic release of AVP within the PVN thereby contributing to sympathoexcitation and hypertension.Support or Funding InformationDepartment of Veterans Affairs Merit Award to NFRThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Sex Differences in Autonomic Response to Hand Grip Exercise Among Individuals with Intellectual Disability
Authors: Sherman Sara R , Hilgenkamp Thessa I.M. , Schroeder Elizabeth C , Fernhall Bo , Baynard Tracy 
Published: June 2021

Individuals with an intellectual disability (ID) are at increased risk for cardiovascular disease (CVD), which may be attributed to autonomic dysfunction. Sex differences in autonomic function are apparent in the general population but have not been investigated in persons with ID, and may help to further explain the high prevalence of CVD. Heart rate variability (HRV) is a non‐invasive measure for autonomic modulation and using a sympatho‐excitatory stimulus such as isometric handgrip (HG) exercise, may reveal altered autonomic function not observed at rest.PURPOSETo assess sex differences in cardiac autonomic function in individuals with and without ID using an isometric handgrip (HG) exercise test.METHODSHRV was assessed in 18 individuals with ID (Male: 9; 28±6yrs, 33±11.1kg/m2) and 23 without ID (Male: 13; 30±9.0yrs, 26±3.8kg/m2) in response to isometric HG exercise at 30% of maximal voluntary contraction. Heart rate was continuously recorded via ECG and the last 2 minutes of quiet rest and HG exercise were analyzed. HRV was analyzed in both the time (root mean square of successive differences (RMSSD) and percentage of RR intervals differing by <50ms (PNN50)) and frequency domains (low and high frequency (LF, HF), and LF/HF ratio). A change score was calculated from HG exercise ‐ baseline.RESULTSThere were no differences between controls and ID. However, males in both groups demonstrated a blunted response to HG exercise in RMSSD, pNN50, and LF (p<0.05) compared to females.CONCLUSIONMales in both groups appear to have a suppressed vagal withdrawal to HG when compared to the females. Future research should investigate autonomic regulation in sex‐specific groups with and without ID in a larger sample size.

Control
ID
ANOVA

Male
Female
Male
Female
Group
Sex
Group*Sex

Time‐Domain

RMSSD (ms2)
−8±9
−21±24
−0±14
−12±12
0.05
0.00
0.35

pNN50 (%)
−6±8
−13± 17
−4± 13
−9± 12
0.26
0.02
0.25

Frequency‐Domain

LF (ms2)
−337± 1098
−1401± 1638
125± 1038
−245±361
0.56
0.00
0.29

HF (ms2)¥
−211±254
−350±428
−118±510
−221±277
0.27
0.10
0.27

LF/HF Ratio§
6± 1
6± 1
6±0
6± 1
0.64
0.65
0.39

Data presented as mean change ± standard deviation.
Control= M (n=13), F (n=9); ID= M (n=9), F (n=9)
Log‐transformed for the case of non‐normal data

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Altered Cardiopulmonary Reflexes Evoked by Irritants in Spontaneously Hypertensive Rats – Effect of Route of Administration and Anesthetics
Authors: Hooper Justin Shane , Taylor‐Clark Thomas 
Published: June 2021

Inhalation of noxious substances such as allyl isothiocyanate (AITC) evoke reflex bradycardia in conscious, healthy animals following the activation of airway nociceptive afferents. These afferents are also activated by air pollutants including particulate matter and ozone. Nevertheless, in patients with cardiovascular disease such pollutants evoke sympathoexcitation (tachycardia, hypertension). We hypothesize that preexisting cardiovascular disease remodels the pulmonary‐cardiac reflexes stimulated by noxious airway stimuli. Here, we studied the cardiopulmonary responses to two separate administration methods of AITC (inhalation and intravenous (i.v.) injection) in conscious and anesthetized normotensive Wistar‐Kyoto rats (WKY) and Spontaneously Hypertensive rats (SH). Both methods of AITC administration evoked bradycardia with increased RR‐interval (RRi) and atrial‐ventricular (AV) block in conscious WKY rats. AITC i.v. evoked similar bradycardic responses in conscious SH rats, however, AITC inhalation evoked a complex brady‐tachycardia which alternated between increased and decreased RRi and both AV block and premature ventricular contractions (PVCs). AITC inhalation caused bradypnea with sporadic episodes of tachypnea in both strains, while only bradypnea was seen after AITC i.v. administration. These responses were shown to be vagally mediated as they were abolished by bilateral vagotomy in a decerebrate model. Anesthesia was also found to prevent the effect of AITC inhalation on HR in both strains, while the bradycardic response to AITC i.v. persisted in the WKY but not in the SH. Furthermore, anesthesia prevented breathing rate responses to inhaled AITC in the SH, but not in the WKY. Differences were also seen in the effects of anesthesia on breathing rate responses to AITC iv between the two strains as bradypnea persisted in the WKY, while the SH was found to have bouts of tachypnea in addition to the bradypnea seen in the conscious studies. The differential responses evoked by AITC in the SH along with the differences in effects of anesthesia on these responses lead us to conclude that multiple unique circuits work independently to control cardiopulmonary reflexes and that preexisting hypertension remodels nociceptive cardiopulmonary reflexes towards sympathoexcitation.Support or Funding InformationNIH SPARC AwardThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Impact of Caffeine on Dynamic Cerebral Autoregulation in Habitual Consumers
Authors: Pizzey Faith K , Tourula Erica N , Theorin Tyler J , Subudhi Andrew W , Pearson James 
Published: June 2021

Caffeine is an adenosine receptor antagonist that is consumed daily by 90% of the United States population and can lead to adenosine receptor upregulation. In caffeine‐naïve individuals, drinking caffeine increases dynamic cerebral autoregulation as assessed by the rate of regulation (RoR) but the influence of caffeine in habitual users is unclear. We aimed to investigate whether dynamic cerebral autoregulation in middle and posterior cerebral arteries was altered by caffeine consumption in habituated consumers. Nine healthy subjects (age: 27 ± 6 yrs, Ht: 179 ± 14 cm, Wt: 76.1 ± 13.6 kg) completed three trials where they drank (6.25ml/kg body mass) either caffeinated coffee (CAF; 4mg caffeine/kg body mass), decaffeinated coffee (DECAF), or water (WATER). Before subjects drank anything (pre drink) we measured mean arterial pressure (MAP; mmHg), middle (MCAv; cm/s) and posterior (PCAv; cm/s) cerebral artery blood velocities at baseline and then during two successive thigh occlusion/release protocols to examine dynamic cerebral autoregulation (Rate of Regulation: RoR, 1/s). Subjects were then given one of the three drinks in a double‐blind, counterbalanced design. Thirty minutes later baseline measurements and the assessment of RoR were repeated (post drink). MAP decreased 14 ± 4 mmHg across all trials following thigh cuff deflation in the assessment of RoR pre drink. Pre drink RoR in the MCA was CAF: 0.19 ± 0.13, DECAF: 0.21 ± 0.14 and WATER: 0.21 ± 0.09 1/s. Pre drink RoR in the PCA was CAF: 0.24 ± 0.18, DECAF: 0.16 ± 0.15 and WATER: 0.23 ± 0.12 1/s. MAP increased from pre to post drink (CAF: 84 ± 7 to 98 ± 6 mmHg; DECAF: 88 ± 10 to 95 ± 6 mmHg and WATER: 89 ± 9 to 97 ± 5 mmHg; p = 0.002), but was not different between trials (p > 0.05). MAP decreased 14 ± 3 mmHg across all trials following thigh cuff deflation in the assessment of RoR post drink. Post drink, MCA RoR demonstrated an interaction effect between trial and time (p = 0.047) and a main effect of time (p = 0.042). Post drink MCA RoR increased in the CAF trial relative to pre drink (0.40 ± 0.17 1/s; p = 0.008) but was unchanged in DECAF (0.23 ± 0.12 1/s) and WATER trials (0.23 ± 0.11 1/s) (both p > 0.05 vs. pre drink). Post drink, PCA RoR was not different relative to pre drink (CAF: 0.35 ± 0.13, DECAF: 0.20 ± 0.11 and WATER: 0.21 ± 0.10 1/s) and did not demonstrate a main effect of time (p = 0.335), trial (p = 0.081) nor an interaction effect (p = 0.414). These findings suggest that caffeine consumption increases dynamic cerebral autoregulation in habituated consumers and supports the increased RoR found in the MCA following caffeine administration in caffeine naïve individuals.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Intraluminal Nutrients Modulate Intracellular Calcium Activity in the Enteric Nervous System of Adult Mice
Authors: Cavin Jean‐Baptiste , Glover Joel , MacNaughton Wallace K. , Sharkey Keith A. 
Published: June 2021

BackgroundIt has long been hypothesized that enteric neurons are able to detect nutrients present in the intestinal lumen, but direct evidence in intact preparations of the intestine is lacking. Understanding how enteric neurons react to changes in dietary constituents will open new avenues for discoveries on the relation between nutrition, modulation of gut function, and health.AimTo measure neuronal activity in the enteric nervous system in response to luminal nutrients.MethodsWe have designed chambers allowing us to visualize, record and quantify intracellular calcium activity in 3D live‐cell confocal recordings of neurons from intact, whole thickness segments of mouse intestine. Twenty mice expressing the genetically encoded calcium reporter Gcamp6 under the control of the pan‐neuronal Wnt1 promoter were used to record intracellular calcium activity in neurons from the jejunum and colon, while perfusing different nutrients through the lumen. Krebs solution was perfused as control and Ensure®, 10% Intralipid® or 20mM Glucose were used as stimuli. 3D videos of calcium fluorescence in the neuronal network were acquired with a Nikon A1R confocal microscope and calcium dynamics were analyzed using the Imaris software (Bitplane). Results are expressed as relative changes in fluorescence intensity (ΔF/F) ± SEM among the neuronal populations studied.ResultsPerfusion of the intestine with Ensure® (liquid meal replacement) increased the fluorescence intensity in reactive neurons by 670 ± 270% in the jejunum and 403 ± 62% in the colon. Peak amplitude was measured on average 5–6 minutes after the initiation of the nutrient perfusion. Perfusion with 10% Intralipid® (lipid emulsion) increased the fluorescence intensity in reactive neurons by 300 ± 180% in the jejunum and 150 ± 15% in the colon. On the other hand, perfusion of the intestine with Glucose (20mM in Krebs solution) lowered baseline fluorescence intensity in a population of neurons by −91 ± 3% in the jejunum and −80 ± 3% in the colon. The percentage of neurons reacting to intraluminal stimuli was dependent on the stimulus and was different between the jejunum and the colon, indicating that subpopulations of neurons might differentially react to different nutrient stimuli.ConclusionsWe report the existence of slow intracellular calcium changes in the neurons in the intestine that vary depending on the nutrient content of the intestinal lumen. The origin and functional consequences of these changes in intracellular calcium activity as well as the identity of responding neurons are currently under investigation.Support or Funding InformationFunding sources: Canadian institutes of Health Research, Alberta Innovates, Human Frontier Science Program.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Regulation of NKCC2 Ubiquitination by the Skp1‐Cullin1‐FBox Complex in Thick Ascending Limbs
Authors: Ares Gustavo 
Published: June 2021

NaCl reabsorption by the thick ascending limb (TAL) is mediated by the Na/K/2Cl cotransporter NKCC2. Nitric oxide and atrial natriuretic peptide decrease NaCl absorption in the thick ascending limb (TAL) by increasing the second messenger cyclic guanosine monophosphate (cGMP). We recently showed that NKCC2 is constitutively ubiquitinated, and that cGMP enhances the rate of ubiquitination. Ubiquitination is a post‐translational modification mediated by the ubiquitin‐activating enzyme (E1), the ubiquitin‐conjugating enzyme (E2), and the ubiquitin ligase (E3). The SCF (Skp1, Cullin‐1, F‐box protein) complex, is the largest family of E3 ubiquitin ligases in mammals. Therefore, we hypothesized that the SCF complex mediates the cGMP‐stimulated NKCC2 ubiquitination in rats TAL. To test our hypothesis we first tested whether we could inhibit neddylation of cullin‐1 with the inhibitor MLN4924 (1 μM). TALs samples were incubated for 60 minutes at 37°C in the presence or absence of the inhibitor, samples were lysed and we measured neddylated cullin‐1 by Western blot. As expected, neddylation of cullin‐1 was blunted in MLN4924 treated samples (baseline: 100%; MLN4924: 11.0 ± 3.5%, p<0.05). We then study whether inhibition of cullin‐1 inhibits the cGMP‐stimulated NKCC2 ubiquitination. TALs suspension from Sprague‐Dawley rats were aliquoted in 4 samples in the presence of the proteasomal inhibitor (MG132 20μM) to stop protein degradation. Then aliquots were incubated at 37°C in the presence or absence of MLN4924 for 10 minutes, and treated with vehicle or db‐cGMP 500 μM at 37°C for an extra 50 minutes. We found that blocking neddylation of cullin‐1, inhibits the cGMP‐stimulated NKCC2 ubiquitination (baseline: 100%; db‐cGMP 500μM: 162.5 ± 10.3%; MLN4924: 75.1 ± 20.2%; MLN4924 + db‐cGMP 500μM: 96.8 ± 19.6%, p<0.05). To further test our hypothesis, we generated a peptide containing the conserved sequence of F‐Box proteins, called the F‐Box domain, to compete for the binding site between native F‐Box proteins to the SCF complex. We used a chariot to facilitate the delivery of the peptide into the TAL cells. We found that the F‐Box peptide binds to the SCF complex by the pull down of cullin‐1, and inhibits the cGMP‐stimulated NKCC2 ubiquitination (F‐Box peptide: 100%; F‐Box peptide + db‐cGMP 500μM: 89.8 ± 3.9%, n.s.). Our data indicates that blocking neddylation of cullin‐1 or impairment the binding of the native F‐Box proteins to the SCF complex inhibits the cGMP‐dependent increase in NKCC2 ubiquitination. We conclude that the cGMP‐dependent increase in NKCC2 ubiquitination is mediated by the SCF complex. To our knowledge, this is the first evidence pointing to the E3 ubiquitin ligase complex involved in the ubiquitination of NKCC2 in native TALs.Support or Funding InformationInstitutional Mentored Grant Program‐Henry Ford Health SystemThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Gene Expression Profiling in Male Mice with Kidney Specific KO of the Circadian Gene Bmal1
Authors: Masten Sarah Howland , Crislip Gene Ryan , Douma Lauren , Matheny Irma Jeanette , Holzworth Meaghan , Cheng Kit‐Yan , Esser Karyn , Wingo Charles , Gumz Michelle L 
Published: June 2021

Nearly all living organisms contain an internal circadian clock that regulates physiological functions. This mechanism is regulated by isoforms of four core transcriptional factors: Cryptochrome (CRY), Period (PER), CLOCK, and BMAL. Every clock gene knockout to date affects blood pressure, highlighting the importance of circadian proteins in physiological homeostasis. Recently we found that kidney‐specific BMAL1 KO mice (KS‐BMAL KO) exhibit a lower blood pressure at baseline when compared to their littermate controls. The goal of this study was to explore potential mechanisms that contribute to this phenotype. Because BMAL1 functions as a transcription factor, we focused on changes in mRNA expression.Our previous data with kidney‐specific PER1 KO mice revealed changes in expression of genes related to renal sodium reabsorption (Douma et. al, 2018). Thus, we hypothesized that KS‐BMAL KO mice may also have differences in the expression of renal sodium handling genes compared to control mice.Kidneys were collected from male kidney‐specific cadherin Cre+ (KS‐BMAL KO) and Cre‐(control) mice at noon and midnight. RNA was isolated and converted to cDNA using reverse‐transcriptase with random hexamers. Finally, a candidate gene approach was used with quantitative RT‐PCR to compare relative gene expression between control and KS‐BMAL KO mice at noon and midnight.After measuring gene expression for numerous sodium transporters, we found none were differentially regulated between KS‐BMAL KO and control mice. Some of these genes, such as NCC and aENaC, did exhibit significant changes in expression between noon and midnight (~20% higher expression at noon vs midnight, n=6 at noon, n=4 at midnight, P<0.05). However, in noon samples, KS‐BMAL KO mice exhibited a significant 50% increase in ATP12A, the transcript that codes for the catalytic subunit of the non‐gastric H+/K+ ATPase (p<0.01, n=6). Additionally, other potassium channels were differentially regulated, including ROMK, a voltage gated potassium channel, which was increased by 85% in KS‐BMAL KO mice. (p<0.05, n=4).Unlike the KS‐PER1 KO mice, KS‐BMAL1 KO mice do not appear to have differences in expression of sodium handling genes. Rather, alterations in the intra‐renal mechanisms of potassium handling may play a critical role to reduce systemic blood pressure.Support or Funding InformationNIH/NIDDK 1R01DK109570, The Gatorade Trust through the UF Department of MedicineThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Intrarenal Metabolite (α‐Ketoglutarate) Signaling Pathway Is Activated by Hnf1α‐Mediated Transcriptional Regulation of OAT10
Authors: Grimm P. Richard , Wellling Paul A 
Published: June 2021

We recently discovered an unusual pathway that couples alterations in intermediate metabolism to salt retention. We found that thiazide diuretics or genetic loss of NCC phosphorylation (SPAK KO) or hypokalemia with intravascular volume contraction activates the synthesis and secretion of α‐ketoglutarate (αKG) from the proximal tubule (PT). αKG is then delivered in the tubular fluid to the distal nephron where it activates its cognate G‐protein coupled receptor, OxGR1, and this stimulates a salt reabsorption network (Pendrin/NDCBE) as a part of a homeostatic response that limits urinary sodium and potassium loss. Hypokalemia appears to stimulate αKG synthesis, whereas volume contraction stimulates αKG transport through angiotensin II (AngII). In the present study, we explore the mechanism by which αKG secretion is activated.Gene profiling studies identified OAT10 (Slc22a13) as an upregulated gene in each of the hypokalemic volume contraction models. As assessed by quantitative immunofluorescence confocal microscopy, OAT10 localized to the PT, and was increased at the apical membrane in SPAK null and thiazide treated WT mice relative to WT control mice. In LLC‐PK1 cells (porcine PT model), we found AngII (100nM) was sufficient to increase OAT10 transcript abundance, and protein localization at the apical membrane. siRNA mediated knockdown of OAT10 resulted in a proportional decrease in αKG secretion. Taken together, the results indicate that OAT10 is regulated to stimulate αKG secretion in response to hypokalemic volume contraction.Activation of OAT10 gene expression is paralleled by up‐regulation of 7 other PT genes that transport amino‐acid substrates for αKG synthesis. In silico promoter analysis (1500bp from start codon) identified Hnf1α as a candidate transcriptional regulator of all these transport genes. Treating LLC‐PK1 cells with AngII decreased phosphorylated Hnf1α and increased its nuclear localization. Luciferase assays using the porcine and mouse Slc22a13 promoter verified that Hnf1α mediates AngII‐stimulated transcription of OAT10 gene.Collectively these data support OAT10 as a mediator of regulated PT αKG secretion and demonstrate that AngII stimulates Slc22a13 transcription via Hnf1α.Support or Funding InformationSupport was provided to PAW from NIH (DK63049, DK54231, and DK093501) and to PRG from the National Kidney Foundation of Maryland.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.