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Honka H, Bhattacharjee J, Zadeh M, Kohli R, Gastaldelli A, Salehi M. Vagal activation alters prandial bile acid composition and glycemia in patients with hypoglycemia after Roux-en-Y gastric bypass surgery. Neurogastroenterol Motil 2024; 36:e14763. [PMID: 38342974 DOI: 10.1111/nmo.14763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/07/2023] [Accepted: 02/01/2024] [Indexed: 02/13/2024]
Abstract
BACKGROUND Altered prandial glycemic response after Roux-en-Y gastric bypass (RYGB) is exaggerated in patients with post-RYGB hypoglycemia. Increased contribution of glucagon-like peptide 1 (GLP-1) to prandial insulin secretion plays a key role in developing hypoglycemia after RYGB, but the role of nonhormonal gut factors remains unknown. Here, the effect of vagal activation on prandial bile acid (BA) composition in relation to glucose, insulin and gut hormone responses was examined in a small size group of nondiabetic subjects after RYGB with intact gallbladder compared to nonoperated controls. METHODS Concentrations of blood glucose, hormones, and BAs were measured in two RYGB subjects with documented hypoglycemia (HGB), three asymptomatic RYGB-treated subjects (AGB), and four nonoperated controls with intact gallbladders during a meal-tolerance test with (MTT-Sham) and without (MTT) preceding modified sham feeding (chew and spit). KEY RESULTS Meal ingestion raised serum total BAs in RYGB-treated subjects without any effect in nonoperated controls. Modified sham feeding similarly increased meal-induced responses of conjugated BAs (CBAs) in all subjects (p < 0.05 compared to MTT alone), whereas unconjugated BAs (UBAs), mainly deoxycholic and chenodeoxycholic acid, were raised only in the HGB group (p < 0.001 for interaction). Prandial UBAs had an inverse correlation with glucose nadir (r = -0.75, p < 0.05) and were directly associated with ISR and GLP-1 during MTT-Sham. CONCLUSIONS & INFERENCES In this small cohort, vagal activation by modified sham feeding increases prandial CBAs in both operated and nonoperated subjects but enhances UBAs only in patients with documented post-RYGB hypoglycemia. Our findings highlight a potential role for nonhormonal gut factors, such as BA and gut microbiome, in glucose abnormalities after RYGB.
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Affiliation(s)
- Henri Honka
- Division of Diabetes, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Jashdeep Bhattacharjee
- Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital Los Angeles, Los Angeles, California, USA
| | - Mansour Zadeh
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Rohit Kohli
- Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital Los Angeles, Los Angeles, California, USA
| | - Amalia Gastaldelli
- Cardiometabolic Risk Unit, Institute of Clinical Physiology-National Research Council, Pisa, Italy
| | - Marzieh Salehi
- Division of Diabetes, University of Texas Health Science Center, San Antonio, Texas, USA
- Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
- South Texas Veterans Health Care System, Audie Murphy Hospital, San Antonio, Texas, USA
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2
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Cholinergic signaling mediates the effects of xenin-25 on secretion of pancreatic polypeptide but not insulin or glucagon in humans with impaired glucose tolerance. PLoS One 2018; 13:e0192441. [PMID: 29466430 PMCID: PMC5821323 DOI: 10.1371/journal.pone.0192441] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 01/10/2018] [Indexed: 01/14/2023] Open
Abstract
We previously demonstrated that infusion of an intestinal peptide called xenin-25 (Xen) amplifies the effects of glucose-dependent insulinotropic polypeptide (GIP) on insulin secretion rates (ISRs) and plasma glucagon levels in humans. However, these effects of Xen, but not GIP, were blunted in humans with type 2 diabetes. Thus, Xen rather than GIP signaling to islets fails early during development of type 2 diabetes. The current crossover study determines if cholinergic signaling relays the effects of Xen on insulin and glucagon release in humans as in mice. Fasted subjects with impaired glucose tolerance were studied. On eight separate occasions, each person underwent a single graded glucose infusion- two each with infusion of albumin, Xen, GIP, and GIP plus Xen. Each infusate was administered ± atropine. Heart rate and plasma glucose, insulin, C-peptide, glucagon, and pancreatic polypeptide (PP) levels were measured. ISRs were calculated from C-peptide levels. All peptides profoundly increased PP responses. From 0 to 40 min, peptide(s) infusions had little effect on plasma glucose concentrations. However, GIP, but not Xen, rapidly and transiently increased ISRs and glucagon levels. Both responses were further amplified when Xen was co-administered with GIP. From 40 to 240 min, glucose levels and ISRs continually increased while glucagon concentrations declined, regardless of infusate. Atropine increased resting heart rate and blocked all PP responses but did not affect ISRs or plasma glucagon levels during any of the peptide infusions. Thus, cholinergic signaling mediates the effects of Xen on insulin and glucagon release in mice but not humans.
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Al-Shboul OA, Al-Dwairi AN, Alqudah MA, Mustafa AG. Gender differences in the regulation of MLC 20 phosphorylation and smooth muscle contraction in rat stomach. Biomed Rep 2018; 8:283-288. [PMID: 29599980 DOI: 10.3892/br.2018.1053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/19/2018] [Indexed: 01/03/2023] Open
Abstract
Evidence of sex-related differences in gastrointestinal (GI) functions has been reported in the literature. In addition, various GI disorders have disproportionate prevalence between the sexes. An essential step in the initiation of smooth muscle contraction is the phosphorylation of the 20-kDa regulatory myosin light chain (MLC20) by the Ca2+/calmodulin-dependent myosin light chain kinase (MLCK). However, whether male stomach smooth muscle inherits different contractile signaling mechanisms for the regulation of MLC20 phosphorylation from that in females has not been established. The present study was designed to investigate sex-associated differences in the regulation of MLC20 phosphorylation and thus muscle contraction in gastric smooth muscle cells (GSMCs). Experiments were performed on GSMCs freshly isolated from male and female rats. Contraction of the GSMCs in response to acetylcholine (ACh), a muscarinic agonist, was measured via scanning micrometry in the presence or absence of the MLCK inhibitor, ML-7. Additionally, the protein levels of MLC20, MLCK and phosphorylated MLC20 were measured by ELISA. The protein levels of MLC20 and MLCK were indifferent between the sexes. ACh induced greater contraction (P<0.05) as well as greater MLC20 phosphorylation (P<0.05) in male GSMCs compared with female. Pretreatment of GSMCs with ML-7 significantly reduced the ACh-induced contraction (P<0.05) and MLC20 phosphorylation (P<0.05) in the male and female cells, and notably, abolished the contractile differences between the sexes. In conclusion, MLC20 phosphorylation and thus muscle contraction may be activated to a greater extent in male rat stomach compared with that in females.
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Affiliation(s)
- Othman A Al-Shboul
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Ahmed N Al-Dwairi
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Mohammad A Alqudah
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Ayman G Mustafa
- Department of Anatomy, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
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4
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McGregor AJ, Beauchamp GA, Wira CR, Perman SM, Safdar B. Sex as a Biological Variable in Emergency Medicine Research and Clinical Practice: A Brief Narrative Review. West J Emerg Med 2017; 18:1079-1090. [PMID: 29085541 PMCID: PMC5654878 DOI: 10.5811/westjem.2017.8.34997] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/18/2017] [Accepted: 08/21/2017] [Indexed: 12/16/2022] Open
Abstract
The National Institutes of Health recently highlighted the significant role of sex as a biological variable (SABV) in research design, outcome and reproducibility, mandating that this variable be accounted for in all its funded research studies. This move has resulted in a rapidly increasing body of literature on SABV with important implications for changing the clinical practice of emergency medicine (EM). Translation of this new knowledge to the bedside requires an understanding of how sex-based research will ultimately impact patient care. We use three case-based scenarios in acute myocardial infarction, acute ischemic stroke and important considerations in pharmacologic therapy administration to highlight available data on SABV in evidence-based research to provide the EM community with an important foundation for future integration of patient sex in the delivery of emergency care as gaps in research are filled.
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Affiliation(s)
- Alyson J McGregor
- Warren Alpert Medical School of Brown University, Department of Emergency Medicine, Division of Sex and Gender in Emergency Medicine, Providence, Rhode Island
| | - Gillian A Beauchamp
- Oregon Health & Science University, Department of Emergency Medicine, Portland, Oregon
| | - Charles R Wira
- Yale University School of Medicine, Department of Emergency Medicine, New Haven, Connecticut
| | - Sarah M Perman
- University of Colorado, School of Medicine, Department of Emergency Medicine, Aurora, Colorado
| | - Basmah Safdar
- Yale University School of Medicine, Department of Emergency Medicine, New Haven, Connecticut
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Al-Shboul O. The role of the RhoA/ROCK pathway in gender-dependent differences in gastric smooth muscle contraction. J Physiol Sci 2016; 66:85-92. [PMID: 26391686 PMCID: PMC10717576 DOI: 10.1007/s12576-015-0400-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 09/07/2015] [Indexed: 12/20/2022]
Abstract
Gender-related differences in various gastric functions and diseases have been reported, with women having a higher prevalence of gastrointestinal disturbances than men. The aim of this study was to investigate sex-dependent differences in activation of the Rho-associated protein kinase (ROCK; RhoA/Rho kinase) pathway and muscle contraction in the stomach using single gastric smooth muscle cells (GSMC) from male and female Sprague-Dawley rats. Expression of ROCK1 and ROCK2 protein and acetylcholine (ACh)-induced activation of RhoA and ROCK were measured using a specifically designed enzyme-linked immunosorbent assay and activity assay kits, respectively. Contraction of a single GSMC was measured by scanning micrometry in the presence or absence of the ROCK inhibitor Y27632 dihydrochloride. ACh-induced activation of RhoA and ROCK and subsequent contraction were greater in male rats than in female rats but neither was related to differences in the expression of ROCK1 or ROCK2 or total RhoA amount. Most important, Y27632 inhibited and abolished differences in ACh-induced contraction in both sexes. In conclusion, increased ACh-induced contraction in the GSMC of male rats is attributable to greater RhoA/ROCK activation independent of differences in the expression of ROCK isoforms or total RhoA.
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Affiliation(s)
- Othman Al-Shboul
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid, 22110, Jordan.
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6
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Zhao YF, Guo XJ, Zhang ZS, Ma XQ, Wang R, Yan XY, He J. Epidemiology of functional diarrhea and comparison with diarrhea-predominant irritable bowel syndrome: a population-based survey in China. PLoS One 2012; 7:e43749. [PMID: 22937091 PMCID: PMC3427143 DOI: 10.1371/journal.pone.0043749] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 07/23/2012] [Indexed: 12/15/2022] Open
Abstract
Background The epidemiology of functional diarrhea and its impacts on Chinese remain unclear, and there are no data on the comparative epidemiology of functional diarrhea and diarrhea-predominant irritable bowel syndrome (IBS-D). This study was to explore the epidemiology of functional diarrhea and its impacts, and to identify its distinction from IBS-D. Methods and Findings A cross-sectional survey was conducted in 16078 respondents, who were interviewed under a randomized stratified multi-stage sampling design in five cities of China. All respondents completed the modified Rome II questionnaire, and the 36-item Short Form health survey (SF-36) was used for assessing health-related quality of life in 20% of the sample. Overall, 248 respondents (1.54%) had functional diarrhea and 277 (1.72%) had IBS-D. Functional diarrhea was positively associated with increasing age and body mass index (trend test P<0.05). The three most common symptoms for at least 3 weeks in the past months were loose, mushy or watery stools (n = 203, 81.85%), more than three bowel movements a day (n = 100, 40.32%) and having to rush to the toilet to have a bowel movement (n = 72, 29.03%). Meaningful impairment was observed in 5 of the 8 SF-36 domains in respondents with functional diarrhea. The demographics are mostly similar between the respondents with functional diarrhea and IBS-D; however, respondents with IBS-D had more frequent symptoms of diarrhea and even lower scores in SF-36 domains than those with functional diarrhea. Conclusions The prevalence of functional diarrhea in China is substantially lower than that in Western countries and relatively higher than that in other Asian countries. It impaired health-related quality of life, and respondents with IBS-D have even worse quality of life. Further population-based studies are needed to investigate the epidemiology of functional diarrhea and the differences between functional diarrhea and IBS-D.
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Affiliation(s)
- Yan-Fang Zhao
- Department of Health Statistics, Second Military Medical University, Shanghai, China
| | - Xiao-Jing Guo
- Department of Health Statistics, Second Military Medical University, Shanghai, China
| | - Zhan-Sai Zhang
- Testing Center for Occupational Health, Shanghai Institute of Occupational Safety and Health, Shanghai, China
| | - Xiu-Qiang Ma
- Department of Health Statistics, Second Military Medical University, Shanghai, China
| | - Rui Wang
- Department of Health Statistics, Second Military Medical University, Shanghai, China
| | - Xiao-Yan Yan
- Clinical Research Institute, Peking University, Beijing, China
| | - Jia He
- Department of Health Statistics, Second Military Medical University, Shanghai, China
- * E-mail:
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7
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Abstract
The autonomic nervous system is the primary neural mediator of physiological responses to internal and external stimuli. It is composed of 2 branches: the sympathetic nervous system, which mediates catabolic responses, and the parasympathetic nervous system, composed of the vagus nerve, which regulates anabolic responses. As the vagus nerve innervates most tissues involved in nutrient metabolism, including the stomach, pancreas, and liver, activation of vagal efferent activity has the potential to influence how nutrients are absorbed and metabolized. Vagal efferent activity is initially activated at the onset of food intake by receptors in the oropharyngeal cavity and then during food intake postprandially. Vagal efferent innervation of the pancreas contributes to early-phase insulin release as well as to optimizing postprandial insulin release. In the absence of vagal activation, which occurs when glucose is administered intragastrically, postprandial glucose levels are higher and insulin levels blunted compared with when there is activation of oropharyngeal receptors by food. An induction of vagal efferent activity also occurs during chronic pancreatic B-cell challenge with 48-hour glucose infusions. Under these conditions, the compensatory increase in insulin secretion is partially mediated by an increase in vagal efferent activity. In conclusion, the vagus nerve, part of the parasympathetic nervous system, plays a critical role in the regulation of blood glucose levels and is an often overlooked factor contributing to glucose homeostasis.
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Affiliation(s)
- Karen L Teff
- Monell Chemical Senses Center and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, 3500 Market Street, Philadelphia, PA, USA.
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8
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Chang L, Mayer EA, Labus JS, Schmulson M, Lee OY, Olivas TI, Stains J, Naliboff BD. Effect of sex on perception of rectosigmoid stimuli in irritable bowel syndrome. Am J Physiol Regul Integr Comp Physiol 2006; 291:R277-84. [PMID: 16574882 DOI: 10.1152/ajpregu.00729.2005] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In irritable bowel syndrome (IBS) patients, the relationship between sex and sensitivity to visceral stimuli is incompletely understood. Our aim was to evaluate the effect of sex on perceptual responses to visceral stimulation in IBS. Fifty-eight IBS patients (mean age 42+/-1 yr; 34 men, 24 women) and 26 healthy controls (mean age 38+/-3 yr; 9 men, 17 women) underwent barostat-assisted distensions of the rectum and sigmoid colon. Rectal discomfort thresholds were measured using a randomized, phasic distension paradigm before and after repeated noxious sigmoid stimulation (SIG, 60-mmHg pulses). Sex had a significant effect on rectal discomfort thresholds. Women with IBS were the most sensitive (lower thresholds [27+/-2.7 mmHg] and higher ratings), with significantly lower rectal discomfort thresholds compared with men with IBS (38+/-2.3 mmHg) and healthy women who were the least sensitive (41.9+/-3.2 mmHg; both P<0.01). There were no significant differences in rectal discomfort thresholds between healthy men (34+/-4.3 mmHg) and men with IBS. Across both IBS and control groups, women demonstrated a significant lowering of discomfort thresholds after noxious sigmoid stimulation (P<0.01), while men did not. Sex significantly influences perceptual sensitivity to rectosigmoid distension. Women show greater perceptual responses to this paradigm.
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Affiliation(s)
- Lin Chang
- Center for Neurovisceral Sciences and Women's Health, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, and Veterans Affairs Greater Los Angeles Healthcare System, California 90073, USA.
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9
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Frissora CL, Koch KL. The role of gender and biological sex in irritable bowel syndrome. Curr Gastroenterol Rep 2005; 7:257-63. [PMID: 16042908 DOI: 10.1007/s11894-005-0017-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Irritable bowel syndrome (IBS), which is characterized by abdominal pain or discomfort that is associated with altered bowel function (diarrhea, constipation, or alteration between the two), is one of several gastrointestinal motility disorders. IBS affects up to one in five North Americans, mostly women. The reason(s) this disorder is reported more often by women than men, and the role of gender and biological sex in the prevalence, pathophysiology, symptom presentation, impact on quality of life, diagnosis, and response to treatment, are poorly understood. The purpose of this article is to review the evidence surrounding the roles of gender and biological sex in IBS.
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10
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Covasa M, Ritter RC, Burns GA. Cholinergic neurotransmission participates in increased food intake induced by NMDA receptor blockade. Am J Physiol Regul Integr Comp Physiol 2003; 285:R641-8. [PMID: 12775553 DOI: 10.1152/ajpregu.00055.2003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
MK-801, a noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, enhances gastric emptying while increasing food intake. Although our previously reported results implicate the vagus in MK-801's effect on feeding, it is not clear whether vagal motor fibers participate in the feeding response. Control of gastric emptying is exerted, in part, by cholinergic vagal motor neurons. Therefore, we examined the ability of MK-801 to increase meal size in the presence or absence of the muscarinic receptor antagonist atropine methyl nitrate. Both central and systemic administration of MK-801 significantly increased intake of 15% sucrose. Intraperitoneal injection of atropine abolished MK-801-induced increase in sucrose intake, whereas administration into the fourth ventricle had no effect. To determine whether augmentation of cholinergic tone produces an enhancement of food intake in the absence of MK-801, we tested the ability of cisapride, a gastric prokinetic agent that promotes acetylcholine release through an action on presynaptic serotonin (5-HT4) receptors, to increase sucrose consumption. Cisapride (500 microg/kg ip) induced a small but significant increase in 15% sucrose intake (15.5 +/- 0.5 ml) compared with NaCl (13.0 +/- 0.6 ml). Furthermore, when MK-801 (100 microg/kg ip) was given in combination with cisapride, intake was significantly higher (19.8 +/- 0.9 ml) than following either agent given alone. Pretreatment with atropine abolished the cisapride-induced increase in intake (12.1 +/- 0.9 ml) as well as the increased intake induced by combining MK-801 and cisapride. These results suggest that blockade of NMDA-gated ion channels in the hindbrain increases food intake, in part, via a peripheral muscarinic cholinergic mechanism.
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Affiliation(s)
- Mihai Covasa
- Dept. of Nutritional Sciences, College of Health and Human Development, Pennsylvania State Univ., 126 S. Henderson, Univ. Park, PA, 16802-6504, USA.
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11
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Abstract
Irritable bowel syndrome (IBS) is a common functional bowel disorder characterized by abdominal pain and change in defecation pattern. This review addresses the topic of possible sex (genetic, biological) and gender (experiential, perceptual) differences in individuals with and without IBS. Several observations make the topic important. First, there is a predominance of women as compared to men who seek health care services for IBS in the United States and other industrialized societies. Second, menstrual cycle-linked differences are observed in IBS symptom reports. Third, women with IBS tend to report greater problems with constipation and nongastrointestinal complaints associated with IBS. Fourth, serotonin (5-HT3) receptor antagonist and 5-HT4 partial agonist drugs appear to more effectively diminish reports of bowel pattern disruption in women with IBS as compared to men. This review examines sex and gender modulation of gastrointestinal motility and transit, visceral pain sensitivity, autonomic nervous system function, serotonin biochemistry, and differences in health care-seeking behavior for IBS.
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Affiliation(s)
- Margaret Heitkemper
- Dept. of Biobehavioral Nursing & Health Systems, Box 357266, University of Washington, Seattle, WA 98195, USA.
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12
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Stengel PW, Cohen ML. M1 receptor-mediated nitric oxide-dependent relaxation unmasked in stomach fundus from M3 receptor knockout mice. J Pharmacol Exp Ther 2003; 304:675-82. [PMID: 12538821 DOI: 10.1124/jpet.102.042283] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Muscarinic receptors can mediate both contractile and relaxant responses in smooth muscle. The stomach fundus from wild-type mice possesses a neuronal M(1) receptor that mediates relaxation to carbamylcholine and (4-hydroxy-2-butynyl)-1-trimethylammonium-3-chlorocarbanilate chloride (McN-A-343) but is masked by M(3) receptor-mediated contraction to both agonists. When the M(3) receptor was deleted, cholinergic-induced relaxation was unmasked. M(1) receptor antagonism with pirenzepine, nitric oxide (NO) synthase inhibition with N(omega)-nitro-L-arginine methyl ester hydrochloride, and inhibition of neuronal activation with tetrodotoxin abolished relaxation to McN-A-343 in tissues from M(3) receptor knockout mice, supporting the neuronal localization of an M(1) receptor that activated NO release to effect relaxation. However, the cyclooxygenase inhibitor indomethacin did not affect contraction or relaxation to carbamylcholine in stomach fundus from wild-type or M(3) receptor knockout mice, indicating that cyclooxygenase products played no role in these responses. The neuronal M(1) receptor modulated relaxation induced by carbamylcholine and McN-A-343 but not relaxation induced by electric field stimulation of the stomach fundus. These data support the presence of M(1) receptor-mediated relaxation in the stomach and suggest that when the M(3) receptor is eliminated or blocked, M(1) receptor-mediated gastric relaxation may be enhanced, possibly leading to alterations in gastric emptying and subsequent effects on body weight.
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Affiliation(s)
- Peter W Stengel
- Eli Lilly and Company, Lilly Research Laboratories, Neuroscience Research, Lilly Corporate Center, Indianapolis, Indiana 46285, USA.
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13
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Stengel PW, Yamada M, Wess J, Cohen ML. M(3)-receptor knockout mice: muscarinic receptor function in atria, stomach fundus, urinary bladder, and trachea. Am J Physiol Regul Integr Comp Physiol 2002; 282:R1443-9. [PMID: 11959688 DOI: 10.1152/ajpregu.00486.2001] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Negative chronotropic and smooth muscle contractile responses to the nonselective muscarinic agonist carbamylcholine were compared in isolated tissues from M(3)-muscarinic receptor knockout and wild-type mice. Carbamylcholine (10(-8)-3.0 x 10(-5) M) induced a concentration-dependent decrease in atrial rate that was similar in atria from M(3)-receptor knockout and wild-type mice, indicating that M(3) receptors were not involved in muscarinic receptor-mediated atrial rate decreases. In contrast, the M(3) receptor was a major muscarinic receptor involved in smooth muscle contraction of stomach fundus, urinary bladder, and trachea, although differences existed in the extent of M(3)-receptor involvement among the tissues. Contraction to carbamylcholine was virtually abolished in urinary bladder from M(3)-receptor knockout mice, suggesting that contraction was predominantly due to M(3)-receptor activation. However, approximately 50-60% maximal contraction to carbamylcholine occurred in stomach fundus and trachea from M(3)-receptor knockout mice, indicating that contraction in these tissues was also due to M(2)-receptor activation. High concentrations of carbamylcholine relaxed the stomach fundus from M(3)-receptor knockout mice by M(1)-receptor activation. Thus M(3)-receptor knockout mice provided unambiguous evidence that M(3) receptors 1) play no role in carbamylcholine-induced atrial rate reduction, 2) are the predominant receptor mediating carbamylcholine-induced urinary bladder contractility, and 3) share contractile responsibility with M(2) receptors in mouse stomach fundus and trachea.
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Affiliation(s)
- Peter W Stengel
- Neuroscience Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA.
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Jones KL, Russo A, Stevens JE, Wishart JM, Berry MK, Horowitz M. Predictors of delayed gastric emptying in diabetes. Diabetes Care 2001; 24:1264-9. [PMID: 11423513 DOI: 10.2337/diacare.24.7.1264] [Citation(s) in RCA: 204] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To define the predictors of the rate of gastric emptying in patients with diabetes. RESEARCH DESIGN AND METHODS A total of 101 outpatients with diabetes (79 type 1 and 22 type 2) underwent measurements of gastric emptying of a solid/liquid meal (scintigraphy), upper gastrointestinal symptoms (questionnaire), glycemic control (blood glucose concentrations during gastric emptying measurement), and autonomic nerve function (cardiovascular reflexes). RESULTS The gastric emptying of solid and/or liquid was delayed in 66 (65%) patients. Solid (retention at 100 min 64 +/- 3.2 vs. 50.2 +/- 3.6%, P < 0.005) and liquid (retention at 100 min 22.7 +/- 1.7 vs. 16.0 +/- 1.8%, P < 0.001) gastric emptying was slower in women than in men. Of all upper gastrointestinal symptoms (including nausea and vomiting), only abdominal bloating/fullness was associated with slower gastric emptying (P < 0.005). A multiple regression analysis demonstrated that both abdominal bloating/fullness and female sex were predictors of slower gastric emptying of both solids and liquids. CONCLUSIONS We conclude that the presence of abdominal bloating/fullness but not any other upper gastrointestinal symptom is associated with diabetic gastroparesis and that gastric emptying is slower in diabetic women than in diabetic men.
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Affiliation(s)
- K L Jones
- Department of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia.
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Ahrén B, Holst JJ. The cephalic insulin response to meal ingestion in humans is dependent on both cholinergic and noncholinergic mechanisms and is important for postprandial glycemia. Diabetes 2001; 50:1030-8. [PMID: 11334405 DOI: 10.2337/diabetes.50.5.1030] [Citation(s) in RCA: 198] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We studied the mechanisms and physiological relevance of the cephalic insulin response to meal ingestion in 12 healthy women (age 63 +/- 0.4 years; BMI 27.7 +/- 1.7 kg/m2). The ganglionic antagonist, trimethaphan, which impairs neurotransmission across parasympathetic and sympathetic autonomic ganglia, or atropine or saline was given intravenously during the first 15 min after ingestion of a standard meal (350 kcal). During saline infusion, insulin levels increased during the first 10 min after meal ingestion, whereas the first increase in glucose was evident at 15 min. The preabsorptive 10-min insulin response was reduced by 73 +/- 11% by trimethaphan (P = 0.009), accompanied by impaired reduction of glucose levels from 25 to 60 min after meal ingestion (deltaglucose = -1.27 +/- 0.5 [with saline] vs. 0.1 +/- 0.4 mmol/l [with trimethaphan]; P = 0.008). This reduction at 25-60 min in glucose levels correlated significantly to the 10-min insulin response (r = 0.65, P = 0.024). The 10-min insulin response to meal ingestion was also reduced by atropine, but only by 20 +/- 9% (P = 0.045), which was lower than the reduction with trimethaphan (P = 0.004). The preabsorptive insulin response was not accompanied by any increase in circulating levels of gastric inhibitory polypeptide (GIP) or glucagon-like peptide 1 (GLP-1). In conclusion, 1) the early preabsorptive insulin response to meal ingestion in humans can be largely attributed to autonomic activation mediated by noncholinergic and cholinergic mechanisms, 2) this cephalic insulin response is required for a normal postprandial glucose tolerance, and 3) GIP and GLP-1 do not contribute to the preabsorptive cephalic phase insulin response to meal ingestion.
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Affiliation(s)
- B Ahrén
- Department of Medicine, Lund University, Sweden.
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