scholarly journals Luminal hypertonicity and acidity modulate colorectal afferents and induce persistent visceral hypersensitivity

2012 ◽  
Vol 303 (7) ◽  
pp. G802-G809 ◽  
Author(s):  
Jun-Ho La ◽  
Bin Feng ◽  
Erica S. Schwartz ◽  
Pablo R. Brumovsky ◽  
G. F. Gebhart
Keyword(s):  
Abdominal Pain ◽  
Sensory Neurons ◽  
Lactose Intolerance ◽  
Behavioral Responses ◽  
Enteric Infection ◽  
Pelvic Nerve ◽  
Carbohydrate Malabsorption ◽  
Digestive Disorder ◽  
Two Factors

Carbohydrate malabsorption such as in lactose intolerance or enteric infection causes symptoms that include abdominal pain. Because this digestive disorder increases intracolonic osmolarity and acidity by accumulation of undigested carbohydrates and fermented products, we tested whether these two factors (hypertonicity and acidity) would modulate colorectal afferents in association with colorectal nociception and hypersensitivity. In mouse colorectum-pelvic nerve preparations in vitro, afferent activities were monitored after application of acidic hypertonic saline (AHS; pH 6.0, 800 mosM). In other experiments, AHS was instilled intracolonically to mice and behavioral responses to colorectal distension (CRD) measured. Application of AHS in vitro excited 80% of serosal and 42% of mechanically-insensitive colorectal afferents (MIAs), sensitizing a proportion of MIAs to become mechanically sensitive and reversibly inhibiting stretch-sensitive afferents. Acute intracolonic AHS significantly increased expression of the neuronal activation marker pERK in colon sensory neurons and augmented noxious CRD-induced behavioral responses. After three consecutive daily intracolonic AHS treatments, mice were hypersensitive to CRD 4–15 days after the first treatment. In complementary single fiber recordings in vitro, the proportion of serosal class afferents increased at day 4; the proportion of MIAs decreased, and muscular class stretch-sensitive afferents were sensitized at days 11–15 in mice receiving AHS. These results indicate that luminal hypertonicity and acidity, two outcomes of carbohydrate malabsorption, can induce colorectal hypersensitivity to distension by altering the excitability and relative proportions of colorectal afferents, suggesting the potential involvement of these factors in the development of abdominal pain.

Sodium Channel Blocking Actions of the κ-Opioid Receptor Agonist U50,488 Contribute to Its Visceral Antinociceptive Effects

2002 ◽  
Vol 87 (3) ◽  
pp. 1271-1279 ◽  
Author(s):  
X. Su ◽  
S. K. Joshi ◽  
S. Kardos ◽  
G. F. Gebhart
Keyword(s):  
Sodium Channel ◽  
Opioid Receptor ◽  
Sensory Neurons ◽  
Receptor Agonist ◽  
Dependent Manner ◽  
Pelvic Nerve ◽  
Opioid Receptor Agonist ◽  
Antinociceptive Effects ◽  
Channel Blocking

The goal of the present study was to determine whether the κ-opioid receptor agonist (ORA) U50,488 attenuates behavioral and primary afferent nerve responses to noxious colorectal distension (CRD) by sodium channel blockade. We tested the analgesic κ-ORA (±)- trans U50,488, its enantiomers (−)- trans(1S,2S)-U50,488 and non κ-ORA (+)- trans (1R,2R)-U50,488, and/or its diastereomer (−)- cis (1S,2R)-U50,488 for their ability to attenuate visceromotor and pelvic nerve afferent fiber responses to noxious CRD in vivo and voltage-activated sodium current in colon sensory neurons in vitro. In unanesthetized rats, subcutaneous administration of U50,488, (1S,2S)-U50,488, and (1R,2R)-U50,488 attenuated the behavioral visceromotor response to noxious CRD; the rank order of potency was: (1S,2S)-U50,488 > U50,488 ≫ (1R,2R)-U50,488. U50,488 and its stereoisomers also inhibited responses of decentralized pelvic nerve afferent fibers to noxious CRD in a dose-dependent manner. Cumulative doses of 16 mg/kg of (1S,2S)-U50,488, (1S,2R)-U50,488, and (1R,2R)-U50,488 reduced responses to a mean 29, 30, and 47% of control, respectively. The mean inhibitory doses of these drugs were not different (range: 6.6–10.8 mg/kg). Sodium channel blockers mexiletine and carbamazepine mimicked the effect of U50,488. In contrast, the κ-ORAs dynorphin (1–13) and ICI 204,488 were ineffective in attenuating pelvic nerve activity. Perfusion of (1S,2S)-U50,488, (1S,2R)-U50,488, or (1R,2R)-U50,488 on colon sensory neurons in vitro decreased voltage-activated sodium currents. This inhibition by U50,488 and its stereoisomers was not opioid receptor–mediated because it could not be reversed by the opioid receptor antagonist naloxone and was also not a G protein–mediated effect. The results reported here suggest that the visceral antinociceptive effects of U50,488 and its stereoisomers are contributed to by their peripheral sodium channel blocking actions.

3 (2) Factorial Design Assisted Crushed Puffed Rice-HPMC-Chitosan based Hydrodynamically Balanced System of Metoprolol Succinate

2020 ◽  
Vol 10 (3) ◽  
pp. 237-249
Author(s):  
Shashank Soni ◽  
Veerma Ram ◽  
Anurag Verma
Keyword(s):  
Drug Release ◽  
Factorial Design ◽  
Hydroxypropyl Methylcellulose ◽  
Batch Size ◽  
Metoprolol Succinate ◽  
Zero Order Kinetics ◽  
Two Factors ◽  
Puffed Rice ◽  
Model Drug

Introduction: Hydrodynamically balanced system (HBS) possesses prolonged and continuous delivery of the drug to the gastrointestinal tract which improves the rate and extent of medications that have a narrow absorption window. The objective of this work was to develop a Hydrodynamically Balanced System (HBS) of Metoprolol Succinate (MS) as a model drug for sustained stomach specific delivery. Materials and Methods: Experimental batches were designed according to 3(2) Taguchi factorial design. A total of 9 batches were prepared for batch size 100 capsules each. Formulations were prepared by physically blending MS with polymers followed by encapsulation into hard gelatin capsule shell of size 0. Polymers used were Low Molecular Weight Chitosan (LMWCH), Crushed Puffed Rice (CPR), and Hydroxypropyl Methylcellulose K15 M (HPMC K15M). Two factors used were buoyancy time (Y1) and time taken for 60% drug release (T60%; Y2). Results: The drug excipient interaction studies were performed by the thermal analysis method which depicts that no drug excipient interaction occurs. In vitro buoyancy studies and drug release studies revealed the efficacy of HBS to remain gastro retentive for a prolonged period and concurrently sustained the release of MS in highly acidic medium. All formulations followed zero-order kinetics. Conclusion: Developed HBS of MS with hydrogel-forming polymers could be an ideal delivery system for sustained stomach specific delivery and would be useful for the cardiac patients where the prolonged therapeutic action is required.

scholarly journals A9 DORSAL ROOT GANGLIA NEURONAL RESPONSES AND SUBSTANCE P PRODUCTION ARE HIGHER IN MALE MICE

2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 10-11
Author(s):  
J Pujo ◽  
G De Palma ◽  
J Lu ◽  
S M Collins ◽  
P Bercik
Keyword(s):  
Abdominal Pain ◽  
Substance P ◽  
Gut Microbiota ◽  
Sensory Neurons ◽  
Dorsal Root ◽  
Neuronal Response ◽  
Neuronal Responses ◽  
Visceral Sensitivity ◽  
Germ Free

Abstract Background Abdominal pain is a common complaint in patients with chronic gastrointestinal disorders. Accumulating evidence suggests that gut microbiota is an important determinant of gut function, including visceral sensitivity. Germ-free (GF) mice have been shown to display visceral hypersensitivity, which normalizes after colonization. Sex also appears to play a key role in visceral sensitivity, as women report more abdominal pain than men. Thus, both gut bacteria and sex are important in the regulation of gut nociception, but the underlying mechanisms remain poorly understood. Aims To investigate the role of gut microbiota and sex in abdominal pain. Methods We used primary cultures of sensory neurons from dorsal root ganglia (DRG) of female and male conventionally raised (SPF) or germ-free (GF) mice (7–18 weeks old). To study the visceral afferent activity in vitro, calcium mobilization in DRG sensory neurons was measured by inverted fluorescence microscope using a fluorescent calcium probe Fluo-4 (1mM). Two parameters were considered i) the percentage of responding neurons ii) the intensity of the neuronal response. First, DRG sensory neurons were stimulated by a TRPV1 agonist capsaicin (12.5nM, 125nM and 1.25µM) or by a mixture of G-protein coupled receptors agonist (GPCR: bradykinin, histamine and serotonin; 1µM, 10µM and 100µM). We next measured the neuronal production of substance P and calcitonin gene-related peptide (CGRP), two neuropeptides associated with nociception, in response to capsaicin (1.25µM) or GPCR agonists (100µM) by ELISA and EIA, respectively. Results The percentage of neurons responding to capsaicin and GPCR agonists was similar in male and female SPF and GF mice. However, the intensity of the neuronal response was higher in SPF male compared to SPF female in response to capsaicin (125nM: p=0.0336; 1.25µM: p=0.033) but not to GPCR agonists. Neuronal activation was similar in GF and SPF mice of both sexes after administration of capsaicin or GPCR agonists. Furthermore, substance P and CGRP production by sensory neurons induced by capsaicin or GPCR agonists was similar in SPF and GF mice, regardless of sex. However, while the response to capsaicin was similar, the GPCR agonists-induced production of substance P was higher in SPF male mice compared to SPF females (p=0.003). The GPCR agonists-induced production of CGRP was similar in SPF male and female mice. Conclusions Our data suggest that at the level of DRG neurons, the absence of gut microbiota does not predispose to visceral hypersensitivity. The intensity of DRG neuronal responses to capsaicin and the GPCR agonists-induced production of substance P are higher in male compared to female mice, in contrast to previously published studies in various models of acute and chronic pain. Further studies are thus needed to investigate the role of sex in visceral sensitivity. Funding Agencies CIHR

scholarly journals Engineered Stem Cells Improve Neurogenic Bladder by Overexpressing SDF-1 in a Pelvic Nerve Injury Rat Model

2020 ◽  
Vol 29 ◽  
pp. 096368972090246 ◽  
Author(s):  
Guan Qun Zhu ◽  
Seung Hwan Jeon ◽  
Kyu Won Lee ◽  
Hyuk Jin Cho ◽  
U-Syn Ha ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Growth Factor ◽  
Neurogenic Bladder ◽  
Rat Model ◽  
Bladder Wall ◽  
Bladder Function ◽  
Pelvic Nerve ◽  
Injured Nerve

There is still a lack of sufficient research on the mechanism behind neurogenic bladder (NB) treatment. The aim of this study was to explore the effect of overexpressed stromal cell-derived factor-1 (SDF-1) secreted by engineered immortalized mesenchymal stem cells (imMSCs) on the NB. In this study, primary bone marrow mesenchymal stem cells (BM-MSCs) were transfected into immortalized upregulated SDF-1-engineered BM-MSCs (imMSCs/eSDF-1+) or immortalized normal SDF-1-engineered BM-MSCs (imMSCs/eSDF-1−). NB rats induced by bilateral pelvic nerve (PN) transection were treated with imMSCs/eSDF-1+, imMSCs/eSDF-1−, or sham. After a 4-week treatment, the bladder function was assessed by cystometry and voiding pattern analysis. The PN and bladder tissues were evaluated via immunostaining and western blotting analysis. We found that imMSCs/eSDF-1+ expressed higher levels of SDF-1 in vitro and in vivo. The treatment of imMSCs/eSDF-1+ improved NB and evidently stimulated the recovery of bladder wall in NB rats. The recovery of injured nerve was more effective in the NB+imMSCs/eSDF-1+ group than in other groups. High SDF-1 expression improved the levels of vascular endothelial growth factor and basic fibroblast growth factor. Apoptosis was decreased after imMSCs injection, and was detected rarely in the NB+imMSCs/eSDF-1+ group. Injection of imMSCs boosted the expression of neuronal nitric oxide synthase, p-AKT, and p-ERK in the NB+imMSCs/eSDF-1+ group than in other groups. Our findings demonstrated that overexpression of SDF-1 induced additional MSC homing to the injured tissue, which improved the NB by accelerating the restoration of injured nerve in a rat model.

scholarly journals Cystitis increases colorectal afferent sensitivity in the mouse

2009 ◽  
Vol 297 (6) ◽  
pp. G1250-G1258 ◽  
Author(s):  
Pablo Rodolfo Brumovsky ◽  
Bin Feng ◽  
Linjing Xu ◽  
Carly Jane McCarthy ◽  
G. F. Gebhart
Keyword(s):  
Urinary Bladder ◽  
Treated Group ◽  
Mechanical Sensitivity ◽  
Pelvic Nerve ◽  
Treatment Groups ◽  
Colon Inflammation ◽  
Afferent Fibers ◽  
Peripheral Mechanism ◽  
Inflammatory Soup

Studies in humans and rodents suggest that colon inflammation promotes urinary bladder hypersensitivity and, conversely, that cystitis contributes to colon hypersensitivity, events referred to as cross-organ sensitization. To investigate a potential peripheral mechanism, we examined whether cystitis alters the sensitivity of pelvic nerve colorectal afferents. Male C57BL/6 mice were treated with cyclophosphamide (CYP) or saline, and the mechanosensitive properties of single afferent fibers innervating the colorectum were studied with an in vitro preparation. In addition, mechanosensitive receptive endings were exposed to an inflammatory soup (IS) to study sensitization. Urinary bladder mechanosensitive afferents were also tested. We found that baseline responses of stretch-sensitive colorectal afferents did not differ between treatment groups. Whereas IS excited a proportion of colorectal afferents CYP treatment did not alter the magnitude of this response. However, the number of stretch-sensitive fibers excited by IS was increased relative to saline-treated mice. Responses to IS were not altered by CYP treatment, but the proportion of IS-responsive fibers was increased relative to saline-treated mice. In bladder, IS application increased responses of muscular afferents to stretch, although no differences were detected between saline- and CYP-treated mice. In contrast, their chemosensitivity to IS was decreased in the CYP-treated group. Histological examination revealed no changes in colorectum and modest edema and infiltration in the urinary bladder of CYP-treated mice. In conclusion, CYP treatment increased mechanical sensitivity of colorectal muscular afferents and increased the proportion of chemosensitive colorectal afferents. These data support a peripheral contribution to cross-organ sensitization of pelvic organs.

scholarly journals An engineered genetic circuit for lactose intolerance alleviation

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Mingyue Cheng ◽  
Zhangyu Cheng ◽  
Yiyan Yu ◽  
Wangjie Liu ◽  
Ruihao Li ◽  
...  
Keyword(s):  
Abdominal Pain ◽  
Lactate Dehydrogenase ◽  
Lactose Intolerance ◽  
Genetic Circuit ◽  
Microbiota Composition ◽  
Galactosidase Activity ◽  
Lactose Malabsorption ◽  
Bacterial Cultures ◽  
Switch Circuit ◽  
Gut Microbiota Composition

Abstract Background Lactose malabsorption occurs in around 68% of the world’s population, causing lactose intolerance (LI) symptoms, such as abdominal pain, bloating, and diarrhea. To alleviate LI, previous studies have mainly focused on strengthening intestinal β-galactosidase activity while neglecting the inconspicuous drop in the colon pH caused by the fermentation of non-hydrolyzed lactose by the gut microbes. A drop in colon pH will reduce the intestinal β-galactosidase activity and influence intestinal homeostasis. Results Here, we synthesized a tri-stable-switch circuit equipped with high β-galactosidase activity and pH rescue ability. This circuit can switch in functionality between the expression of β-galactosidase and expression of L-lactate dehydrogenase in response to an intestinal lactose signal and intestinal pH signal, respectively. We confirmed that the circuit functionality was efficient in bacterial cultures at a range of pH levels, and in preventing a drop in pH and β-galactosidase activity after lactose administration to mice. An impact of the circuit on gut microbiota composition was also indicated. Conclusions Due to its ability to flexibly adapt to environmental variation, in particular to stabilize colon pH and maintain β-galactosidase activity after lactose influx, the tri-stable-switch circuit can serve as a promising prototype for the relief of lactose intolerance.

Developmental programmes of growth and survival in early sensory neurons

1991 ◽  
Vol 331 (1261) ◽  
pp. 259-262
Keyword(s):  
Nervous System ◽  
Sensory Neurons ◽  
Neurotrophic Factor ◽  
Target Distance ◽  
Trophic Factor ◽  
Growth And Survival ◽  
Target Field ◽  
Developing Nervous System

In the developing vertebrate nervous system the survival of neurons becomes dependent on the supply of a neurotrophic factor from their targets when their axons reach these targets. To determine how the onset of neurotrophic factor dependency is coordinated with the arrival of axons in the target field, we have studied the growth and survival of four populations of cranial sensory neurons whose axons have markedly different distances to grow to reach their targets. Axonal growth rate both in vivo and in vitro is related to target distance; neurons with more distant targets grow faster. The onset trophic factor dependency in culture is also related to target distance; neurons with more distant targets survive longer before becoming trophic factor dependent. These data suggest that programmes of growth and survival in early neurons play an important role in coordinating the timing of trophic interactions in the developing nervous system.

scholarly journals Entry of Herpes Simplex Virus Type 1 into Primary Sensory Neurons In Vitro Is Mediated by Nectin-1/HveC

2003 ◽  
Vol 77 (5) ◽  
pp. 3307-3311 ◽  
Author(s):  
Sarah M. Richart ◽  
Scott A. Simpson ◽  
Claude Krummenacher ◽  
J. Charles Whitbeck ◽  
Lewis I. Pizer ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Sensory Neurons ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Primary Cultures ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Primary cultures of rat and mouse sensory neurons were used to study the entry of herpes simplex virus type 1 (HSV-1). Soluble, truncated nectin-1 but not HveA prevented viral entry. Antibodies against nectin-1 also blocked infection of rat neurons. These results indicate that nectin-1 is the primary receptor for HSV-1 infection of sensory neurons.

Sign in / Sign up

Export Citation Format

Share Document