摘要:

Skeletal muscle structure and morphology may be altered in obesity. To study this further, muscles from six genetically obese (fa/fa) and six normal male rats were examined at 15 weeks of age. The gluteus medius, vastus lateralis and rectus abdominis muscles were dissected out and stained for histochemical fibre typing. In addition the fibre cross‐sectional area was measured on a graphic tablet. The proportion of fast twitch fibres was larger in the vastus lateralis and rectus abdominis muscles of the obese rats (P<0.01); no difference was seen for the gluteus medius muscle. For the normal rats the cross‐sectional area of the fast‐twitch fibres was 2–3 times larger than the area of slow‐twitch fibres in the same muscle. The cross‐sectional area of the fast‐twitch fibres in the obese rats was 40–47% less than in the control animals (P<0.003), while no difference between the two groups was found for the slow‐twitch fibre area. The data thus suggest that in the genetically obese rats the development of fast‐twitch fibres was primarily affected. Moreover, in these animals some muscles may be more a

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09938.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09939.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09940.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The effects of streptozotocin‐induced diabetes, physical training and their combination on the activities of prolyl 4‐hydroxylase (PH) and galactosylhydroxylysyl glucosyl‐transferase (GGT), both marker enzymes of collagen biosynthesis, and on the concentration of hydroxyproline (Hyp) were studied in vastus lateralis, rectus femoris and gastrocnemius muscles in rats. The experimental period was 12–16 weeks. Diabetes had an overall decreasing effect on specific PH activity in all muscles studied, whereas specific GGT activity remained at control level. Total PH and GGT activities decreased in all three muscles in the diabetic animals (P<0,001). Training caused an increase in PH and GGT activities in gastrocnemius in non‐diabetic rats, whereas training in combination with diabetes did not change specific PH or GGT activity. Diabetes increased specific Hyp concentration in vastus lateralis and gastrocnemius in trained diabetic rats (P<0.05), whereas training decreased Hyp level significantly (P<0.05) in vastus lateralis in non‐diabetic rats, but not in diabetic animals. The results suggest that in streptozotocin‐induced diabetes the decrease in collagen synthesis rate exceeds the negative total protein balance in the muscle. Although physical training may have an increasing effect on muscular collagen synthesis in non‐diabetic rats, it is unable to prevent the decreasing effect of diabetes on col

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09941.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09942.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Vasostatins are the N‐terminal chromogranin A peptides 7 ˜ 22 kDa. They have been shown to be present in several endocrine tissues and exhibit vasoinhibitory activityin vitro.In a first series of experiments, we investigated the presence and subcellular localization of vasostatins in the bovine splenic nerve. Experimental results, obtained using gradient centrifugation, showed that noradrenaline was enriched 25‐fold in the large dense core vesicle fraction, compared with the original homogenate. In the latter fraction, the 7 and 18 kDa peptides were observed following immunodetection with antiserum to chromogranin A1, 4oand laser densitometric scanning revealed these two fragments as the major N‐terminal fragments. Subsequently, we examined the release of the 7 and 18 kDa peptides from perfused calf spleen during veratridine (20 μM) or 1,1‐dimethyl‐4‐phenylpiperazinium iodide (20 μM) stimulation. In the prestimulatio samples, we were not able to detect these peptides, however, following stimulation, the 7 and 18 kDa chromogranin A fragments became apparent. The vasostatin‐immunoreactivity, in both bovine chromaffin granule lysate and calf spleen perfusate, elutes at the same retention time on reversed‐phase high performance liquid chromatography. The present study demonstrated that vasostatins are present in the large dense core vesicles of sympathetic axons and are released from the nerve terminals in response to stimulation. The release of vasostatins from sympathetic nerves in the spleen suggest anin vivofunction for N‐terminal chromogranin A product

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09944.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The urinary bladder is a compliant organ, high compliance being essential for useful urine storage. The extent to which the sympathetic nervous system promotes the storage of urine by increasing bladder compliance is unclear. The aim of the present study was to determine the range of bladder volumes over which the sympathetic nervous system was to determine the range of bladder volume over which the sympathetic nervous system increased bladder wall compliance. In supine, anaesthetized cats, the bladder was filled at twice the rate of natural filling, the continence cycle being interrupted at five stages. These stages were when the bladder had become globular, during prodromal contractions, soon after non‐micturating contractions had commenced approximately two‐thirds of the way through the continence cycle and just prior to micturition. During each of these interruptions, bladder volume was held constant while pelvic nerve afferent activity and bladder pressure were recorded. Recordings were obtained before and during the intravenous infusion of trimethaphan, the resulting partial ganglion blockade decreasing arterial pressure by a third. Bladder pressure as well as afferent blocked, indicating that there had been a prevailing net sympatho‐inhibitory effect promoting bladder wall relaxation. This effect was observed during prodromal contractions and continued until the onset of micturition. This net sympatho‐inhibitory effect is a potential therapeutic path for the treatement of bladder storage di

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09945.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The objective of this study was to test whether changes in central blood volume can induce reflex effects on sweating. Multi‐unit skin sympathetic nerve activity (SSA) was recorded from the posterior cutaneous nerve of the forearm or radial nerve branches in 11 healthy volunteers. Skin electrical resistance and skin blood flow were recorded in the area innervated by the impaled nerve fascicle. Sudomotor nerve traffic and sweating was induced by whole body heating. Lower body negative pressure (LBNP) and tilting (3d̀ head up) was used for blood volume displacement from the chest to the lower body. Low levels of LBNP (5 and 10 mmHg) had no effect on blood pressure, heart rate or skin blood flow but induced a prompt inhibition of SSA and a reduced number of transient skin resistance changes (n= 9), both rapidly returning to control levels after cessation of LBNP. Quantitatively, the effect was similar at both levels of LBNP. Head up tilting also reduced SSA (n= 3, tilt manoeuvres). A capacity for mental stress‐induced SSA increase remained during LBNP. Spontaneous flucturations in blood pressure did not affect SSA, arguing against arterial (high‐pressure) baroreceptors modulating SSA. Consequently, the present results indicate that unloading of cardiopulmonary (low‐pressure) volume receptors reduces sympathetic sudomotor nerve traffic and sweating in warm subjects. It is suggested that the reflex contributes to counteracting hypo

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09946.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A possible role of endothelin (ET)‐1 in mediating hypoxic pulmonary vasoconstriction (HPV) was examined by comparing haemodynamic differences between ET‐1‐induced vasoconstriction and HPV in isolated perfused rat lungs. An ETAreceptor antagonist (BQ123) was also employed to assess the effects of ET‐1. The pulmonary arterial pressure (Ppa) was significantly increased by alveolar hypoxia (3% O2) and by ET‐1 (5 nM). The pulmonary microvascular pressure was not changed by hypoxia, but increased more than two‐fold by ET‐1 (P<0.01). Hypoxia significantly increased pulmonary arterial resistance (P<0.01) while ET‐1 significantly increased pulmonary venous resistance (P<0.01), and slightly increased arterial resistance. Lung weight was increased by ET‐1 and decreased by hypoxia, accompanied by similarPpa responses in both cases. BQ123 (10‐6mand 10‐5m) did not influence the changes inPpa and lung weight induced by hypoxia or angiotensin II (0.3 μg). BQ123 did, however, suppress (P<0.05) the increase inPpa and lung weight induced by 5 nM ET‐1. Thus, it appears unlikely that ET‐1 is involved in changes in pulmonary vasc

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09947.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

In isolated pancreative β cells from rats the insulin secretory response to glucose is amplified by L‐arginine. Since this effect is inhibited by NO synthesis inhibitors, and since L‐arginine is precursor or NO, the observation indicates a role for NO in insulin secretion from β cells. We recently reported that i. v. L‐arginine elicited insulin secretion in anaesthetized rats by a mechanism that was partly NO dependent. The aim of the present study was to assess if the insulin secretory response to an intravenous infusion of glucose also requires an intact NO formation. Anaesthetized rats were given D‐glucose (100 mg kg‐1min‐1i. v. for 30 min). Plasma insulin (PI), blood glucose (BG) levels and mean arterial blood pressure (MAP) were assessed from before and until 15 min after the end of the infusion. One group of rats were untreated and served as controls. The two other groups were pretreated with either of the NO synthase inhibitorsNw‐nitro‐L‐arginine methyl ester (l‐NAME, 50 mg kg‐1i. v.), orNG‐monomethyl‐L‐arginine (l‐NMMA, 100 mg kg‐1i. v.). In controls infusion of glucose elevated PI by up to 25pL3 UL‐1, and BG by up to 27pL1 mmol L‐1. Pretreatment withl‐NAME elevated MAP from 74pL6 to 132pL4 mmHg, indicating that NO synthase was inhibited. Infusion of glucose in rats pretreated withl‐NAME increased PI by up to 28pL2 UL‐1, and elevated BG by up to 30pL1 mmol L‐1. Pretreatment withl‐NMMA elevated MAP from 80pL5 to 132pL1 mmHg. Infusion of glucose in these rats increased PI by up to 23pL3 UL‐1, and elevated BG by up to 29pL2 mmol L‐1. The PI and BG responses to glucose infusion were not significantly affected by either of the NO synthase inhibitors studied. We conclude that the insulin secretory response to i. v. glucose infusion in

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1995.tb09948.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY