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- Benrick, Anna, 1979, et al.
(författare)
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Interleukin-6 mediates exercise-induced increase in insulin sensitivity in mice.
- 2012
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Ingår i: Experimental physiology. - : Wiley. - 1469-445X .- 0958-0670. ; 97:11 SI, s. 1224-1235
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin-6 (IL-6) is released from working skeletal muscle during exercise. We investigated the acute and the long-term beneficial effects of IL-6 on exercise-induced glucose uptake in skeletal muscle and insulin sensitivity. The acute effect on exercise-induced glucose uptake was measured in IL-6 deficient (-/-) mice and wild type controls using a tracer technique. There was no difference in serum disappearance of 3H-2-deoxyglucose after a bolus dose of exercise between IL-6 -/- and wild type mice (13565 ± 426 vs. 14343 ± 1309 dpm*min/ml, p=0.5). The glucose uptake rate in the EDL muscle was however lower in IL-6 -/- compared to wildtype mice (398 ± 44 vs. 657 ± 41 nmol/g/min, p<0.01). In the long-term study, we monitored insulin sensitivity, serum retinol-binding protein-4 (RBP-4) levels, running activity, food intake, body weight and body composition in IL-6 -/- and wild type mice on a high-fat diet (HFD), with or without access to running wheels. In sedentary IL-6 -/- and wild type mice, HFD decreased insulin sensitivity (glucose AUC increased about 20% during an insulin tolerance test (ITT), p<0.05 for both genotypes vs. baseline) and led to a 30% increase in serum RBP-4 levels (p <0.01 for both genotypes vs. baseline). Wild type runners were protected against these effects of HFD and maintained their baseline insulin sensitivity and serum RBP-4 levels. In contrast, IL-6 -/- mice did not, to the same extent as wild types, benefit from running. IL-6 -/- runners had a similar decrease in insulin sensitivity as their sedentary littermates (glucose AUC during an ITT in runners vs. sedentary IL-6-/- HFD mice: 312 ± 14 vs. 340 ± 22 mmol*min/L, p=0.4) and displayed a 14% increase in serum RBP-4 as compared to baseline levels (p<0.01). Our results indicate that endogenous IL-6 contributes to the exercise-induced increase in insulin sensitivity, but only plays a minor role for glucose uptake into skeletal muscle during exercise.
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- Burggren, Warren, et al.
(författare)
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Breathing patterns and associated cardiovascular changes in intermittently breathing animals: (Partially) correcting a semantic quagmire
- 2024
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Ingår i: Experimental Physiology. - : WILEY. - 0958-0670 .- 1469-445X.
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Forskningsöversikt (refereegranskat)abstract
- Many animal species do not breathe in a continuous, rhythmic fashion, but rather display a variety of breathing patterns characterized by prolonged periods between breaths (inter-breath intervals), during which the heart continues to beat. Examples of intermittent breathing abound across the animal kingdom, from crustaceans to cetaceans. With respect to human physiology, intermittent breathing-also termed 'periodic' or 'episodic' breathing-is associated with a variety of pathologies. Cardiovascular phenomena associated with intermittent breathing in diving species have been termed 'diving bradycardia', 'submersion bradycardia', 'immersion bradycardia', 'ventilation tachycardia', 'respiratory sinus arrhythmia' and so forth. An examination across the literature of terminology applied to these physiological phenomena indicates, unfortunately, no attempt at standardization. This might be viewed as an esoteric semantic problem except for the fact that many of the terms variously used by different authors carry with them implicit or explicit suggestions of underlying physiological mechanisms and even human-associated pathologies. In this article, we review several phenomena associated with diving and intermittent breathing, indicate the semantic issues arising from the use of each term, and make recommendations for best practice when applying specific terms to particular cardiorespiratory patterns. Ultimately, we emphasize that the biology-not the semantics-is what is important, but also stress that confusion surrounding underlying mechanisms can be avoided by more careful attention to terms describing physiological changes during intermittent breathing and diving. What is the topic of this review? This review examines the rather confusing semantics that has been used to describe patterns in the field of cardiorespiratory physiology as it applies to intermittent breathing, particularly in diving species. What advances does it highlight? This review highlights the various cardiorespiratory phenomena associated with intermittent breathing and diving. It highlights the semantic issues associated with describing each and offers a rationale for standardizing terms based on underlying mechanisms to reduce confusion and advance the study of cardiorespiratory phenomena in both medical and comparative physiological investigations.
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- Cannon, Barbara, et al.
(författare)
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Human brown adipose tissue : Classical brown rather than brite/beige?
- 2020
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Ingår i: Experimental Physiology. - 0958-0670 .- 1469-445X. ; 105:8, s. 1191-1200
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Tidskriftsartikel (refereegranskat)abstract
- New Findings What is the topic of this review? It has been suggested that human brown adipose tissue (BAT) is more similar to the brite/beige adipose tissue of mice than to classical BAT of mice. The basis of this is discussed in relationship to the physiological conditions of standard experimental mice.
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- Carpenter, GH, et al.
(författare)
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Altered plasticity of the parasympathetic innervation in the recovering rat submandibular gland following extensive atrophy.
- 2009
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Ingår i: Experimental physiology. - : Wiley. - 0958-0670. ; 94:2, s. 213-9
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Tidskriftsartikel (refereegranskat)abstract
- Adult rat submandibular glands have a rich autonomic innervation, with parasympathetic and sympathetic nerves working in synergy rather than antagonistically. Ligation of the secretory duct rapidly causes atrophy and the loss of most acini, which are the main target cell for parasympathetic nerves. Following deligation, there is a recovery of gland structure and function, as assessed by autonomimetic stimulation. This study examines whether the parasympathetic nerves reattach to new target cells to form functional neuro-effector junctions. Under recovery anaesthesia, the submandibular duct of adult male rats was ligated via an intra-oral approach to avoid damaging the chorda-lingual nerve. Four weeks later, rats were either killed or anaesthetized and the ligation clip removed. Following a further 8 weeks, both submandibular ducts were cannulated under terminal anaesthesia. Salivary flows were then stimulated electrically (chorda-lingual nerve at 2, 5 and 10 Hz) and subsequently by methacholine (whole-body infusion at two doses). Glands were excised, weighed and divided for further in vitro studies or fixed for histological examination. Ligation of ducts caused 75% loss of gland weight, with the loss of most acinar cells. Of the remaining acini, only 50% were innervated despite unchanged choline acetyltransferase activity, suggesting few parasympathetic nerves had died. Following deligation, submandibular glands recovered half their weight and had normal morphology. Salivary flows from both glands (per unit of gland tissue) were similar when evoked by methacholine but greater from the deligated glands when evoked by nerve stimulation. This suggests that parasympathetic nerves had reattached to new target cells in the recovered glands at a greater ratio than normal, confirming reinnervation of the regenerating gland.
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- Cedborg, Anna I. Hardemark, et al.
(författare)
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Co-ordination of spontaneous swallowing with respiratory airflow and diaphragmatic and abdominal muscle activity in healthy adult humans
- 2009
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Ingår i: Experimental Physiology. - : Wiley. - 1469-445X .- 0958-0670. ; 94:4, s. 459-468
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Tidskriftsartikel (refereegranskat)abstract
- Co-ordination of breathing and swallowing is essential for normal pharyngeal function and to protect the airway. To allow for safe passage of a bolus through the pharynx, respiration is interrupted (swallowing apnoea); however, the control of airflow and diaphragmatic activity during swallowing and swallowing apnoea are not fully understood. Here, we validated a new airflow discriminator for detection of respiratory airflow and used it together with diaphragmatic and abdominal electromyography (EMG), spirometry and pharyngeal and oesophageal manometry. Co-ordination of breathing and spontaneous swallowing was examined in six healthy volunteers at rest, during hypercapnia and when breathing at 30 breaths min(-1). The airflow discriminator proved highly reliable and enabled us to determine timing of respiratory airflow unambiguously in relation to pharyngeal and diaphragmatic activity. During swallowing apnoea, the passive expiration of the diaphragm was interrupted by static activity, i.e. an 'active breath holding', which preserved respiratory volume for expiration after swallowing. Abdominal EMG increased throughout pre- and post-swallowing expiration, more so during hyper- than normocapnia, possibly to assist expiratory airflow. In these six volunteers, swallowing was always preceded by expiration, and 93 and 85% of swallows were also followed by expiration in normo- and hypercapnia, respectively, indicating that, in man, swallowing during the expiratory phase of breathing may be even more predominant than previously believed. This co-ordinated pattern of breathing and swallowing potentially reduces the risk for aspiration. Insights from these measurements in healthy volunteers and the airflow discriminator will be used for future studies on airway protection and effects of disease, drugs and ageing.
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- Docherty, N. G., et al.
(författare)
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Improvements in the metabolic milieu following Roux-en-Y gastric bypass and the arrest of diabetic kidney disease
- 2014
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Ingår i: Experimental Physiology. - : Wiley. - 0958-0670. ; 99:9, s. 1146-1153
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Tidskriftsartikel (refereegranskat)abstract
- Roux-en-Y gastric bypass (RYGB) is an efficacious intervention for morbid obesity and has a diabetes-remitting effect in patients with obesity and type 2 diabetes mellitus, which occurs prior to significant weight loss. Roux-en-Y gastric bypass is also associated with early and sustained reductions in the risk factor profile for the progression of diabetic complications. Attention is therefore now being placed on RYGB as a metabolic intervention with the capacity to yield therapeutic benefit in relation to the progression of diabetic complications, such as diabetic kidney disease. As alterations in gut anatomy following RYGB coincide with attendant shifts in downstream enteroendocrine signals with direct and indirect resolutionary effects on the kidney, the concept of an endocrine gut-kidney axis post-RYGB is growing. With the model of a gut-kidney axis in mind, this article summarizes emerging data on the effects of RYGB on risk factors for diabetic kidney disease (hyperglycaemia, dyslipidaemia and hypertension), highlighting a potential role for glucagon-like peptide 1 in risk factor reduction.
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| 10. |
- Edwards, A V, et al.
(författare)
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Nitric oxide and release of the peptide VIP from parasympathetic terminals in the submandibular gland of the anaesthetized cat.
- 1996
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Ingår i: Experimental physiology. - 0958-0670. ; 81:3, s. 349-59
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Tidskriftsartikel (refereegranskat)abstract
- The role of nitric oxide (NO) in mediating various submandibular responses to stimulation of the parasympathetic innervation has been investigated in anaesthetized cats, in which N omega-nitro-L-arginine methyl ester (L-NAME; 30 mg kg-1 I.A.) was used to block the synthesis of NO. L-NAME significantly reduced the vasodilator response and the flow of saliva, together with the output of salivary protein that occurred during stimulation of the chorda lingual nerve (20 Hz for 1 s at 10 s intervals), without significantly reducing the output of vasoactive intestinal peptide (VIP) from the gland. The results show that NO is implicated not only in the release of VIP, as established previously, but also in mediating its actions following release in the submandibular gland of the cat.
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