摘要:

The function and size of the rat ventral prostate are stimulated by androgens and inhibited by estrogens. In order to test whether the blood flow in prostate is influenced in a similar fashion prostatic blood flow was measured after administration of human chorionic gonadotrophin (hCG) in rats with and without pretreatment of estradiol‐17β (E2) and in rats castrated for five days with and without treatment with E2. Prostatic blood flow was measured with the microsphere technique, which allows blood flow measurement without any interference with the organ. E2treatment resulted in a decreased prostatic blood flow in both intact and castrated rats, and blood flow was restored to normal in intact rats after hCG‐injection. It was concluded that the E2induced decrement of prostatic blood flow was at least in part mediated by a direct effect on the pros

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07329.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Pial arterial and venous calibre were continuously recorded through a closed cranial window preparation during cervical sympathetic nerve stimulation in 10 cats before and after alpha‐and beta‐adrenoceptor blockade. In addition, the intracranial pressure (ICP) was simultaneously recorded in 4 of the cats. Under resting conditions 33 arteries (mean diameter 130 μm) constricted by 11.7 ± 0.8% and 80 venous portions (mean diameter 152 μm) constricted by 13.7 ± 0.7% during sympathetic nerve stimulation. ICP decreased simultaneously by 16.5 ± 6.2%. Administration of the alpha‐adrenoceptor antagonist phenoxybenzamine i. v.(1.5 mg · kg‐1) abolished the reduction of ICP and markedly reduced, but did not completely abolish, the constrictor response of arteries and veins. The beta‐adrenoceptor antagonist propranolol (1.5 mg · kg‐1) did not significantly alter the reduction of ICP or the response of pial veins and small arteries, whereas the response of arteries with a diameter>150 μm was attenuated. It is concluded that the constriction of pial veins and arteries during sympathetic stimulation is mediated predominantly via alpha‐adrenoceptors. The sympathetic nerves of cerebral blood vessels may have stronger influence on the cerebral capacitance than on resistance vessels under normotensive and n

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07330.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The enhancement of performance in stretch‐shortening exercises has been attributed to the recoil of elastic energy stored during the stretching phase. If the time between stretching and shortening (coupling time) is too long the stored elastic energy can be wasted. In the present study, coupling time was increased by asking ten male subjects to run on a treadmill at different speeds (2.2–5.2 m × s‐1) using special soft shoes in addition to normal shoes. The results indicated that running with soft shoes required greater energy consumption than running with normal shoes except at slow speed (2.2 m × s‐1). When the running speed was increased the extra energy consumed using soft shoes was parallelly enhanced (0.4 J × kg‐1/step at 5.2 m × s‐1). It was suggested that the effect of coupling time as limiting factor for recoil of elastic energy was relevant in fast twitch (FT) fibers, which were progressively recruited when the running speed was increased. This is consistent to the fact that cross‐bridge life time in FT fibers is very short, and therefore more sensitive to coupling time. At slow running speed (2.2 m ×s s‐1) only slow twitch (ST) fibers were recruited and the enhancement of coupling time was not long enough to provocate detachment of cross‐bridges of ST fibers, which possess a long cross‐bridge life time. It was concluded that the different recruitment of ST and FT fibers influenced the pattern of recoil of elastic energy which was depend

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07331.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Studies on the uptake and storage of sodium and biogenic amines (phenylethylamine, noradrenaline, histamine) by two weak cation‐exchangers, IRC‐50 and Sephadex C‐50, and by biogenic granule‐enriched preparations demonstrated that the synthetic and biogenic materials had several common characteristics. They showed similar concentration‐and pH‐dependence and fitted the same cation‐exchange and receptor‐binding equations. The observations were taken to support the view that the matrices of amine‐storing granules have the properties of weak cation‐exchangers, with carboxyls as the ca

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07332.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Effects of morphine and naloxone were investigated on cerebral, ocular and peripheral blood flow in unanesthetized rabbits. Blood flow measurements were performed with the labelled microsphere method. Cervical sympathotomy was performed on one side the day before the flow determination. Naloxone 2 mg/kg b. w.i. v.had no consistent effect on cerebral, ocular or peripheral blood flow or on mean arterial blood pressure. Morphine 2 mg/kg b. w.i. v.caused a rise in PaCO2of 0.9 kPa and tended to increase cerebral blood flow in all parts investigated. In the hippocampal region, caudate nucleus and collicles the increase in flow was about 30% which is more than expected from the rise in PaCO2· Blood flow in the retina increased while the other parts of the eye showed no consistent changes in blood flow. Morphine reduced the blood flow in the duodenum by 60%. Mean arterial blood pressure did not change after morphine. No effect of the cervical sympathotomy was detected on cerebral or ocular blood flow before or after morphine or naloxone. Thus, we found no evidence for a tonically operating opioid system controlling cerebral, ocular or peripheral blood flow. However, exogenously administrated opiate can influence blood flows in these areas

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07333.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The origin of substance P (SP)‐immunoreactive neurons in the lower respiratory tract, esophagus and heart of guinea‐pigs was demonstrated by surgical denervation or capsaicin pretreatment with subsequent determination of the tissue levels of SP by radioimmunoassay. In other experiments the effect of vagal nerve stimulation on the SP levels in these tissues was studied. The effects of capsaicin‐sensitive afferents in the respiratory tract mucosa and bronchial smooth muscle was also studied by analysis of vascular permeability to Evans blue and insufflation‐pressure changes. Our present data indicate that all SP nerves in the trachea and lung are afferent and capsaicin‐sensitive. The trachea and stem bronchi receive SP afferents mainly from the right vagus nerve with cell bodies located in both the nodose and jugular ganglia. The SP innervation of the lung seems to have a dual origin: 1. Afferents from both vagal nerves with a crossed type of innervation pattern. 2. A non‐vagal source which consists of about 40% of the SP nerves in the lung. These nerves probably originate from thoracic spinal ganglia. The effects of ether and capsaicin on insufflation pressure and increase in vascular permeability were dependent on the integrity of capsaicin‐sensitive afferents of both vagal and non‐vagal origin. In the guinea pig, systemic capsaicin pretreatment to adult animals seemed to result in irreversible changes in the respiratory tract, while in the rat a successive recovery of the functional response of capsaicin‐sensitive afferents occurred. Different regims of systemic capsaicin pretreatment induced different effects on the cholinergic (atropine‐sensitive) insufflation‐pressure response. Capsaicin pretreatment, using multiple injections over two days, depressed the cholinergic insufflation‐pressure increase, while the cholinergic vagal component was unaffected in animals which received a single dose of capsaicin or local pretreatment with capsaicin on the vagal nerves. The local treatment was more effective with regard to SP depletion in target areas when using alcohol as solvent than when capsaicin was dissolved in paraffin oil, while the functional deficits were similar. The SP nerves in the esophagus were mainly of vagal afferent origin, while the heart atrium seemed to have a dual innervation by both vagal

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07334.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The effect of increased tissue pressure on blood flow in subcutaneous and skeletal muscle tissue was studied in 8 healthy humans resting in horizontal position. Blood flow was measured by the local133Xe washout technique in the mid‐calf region. Tissue pressure in the depot area was increased by inflating a compression cuff, 50 cm wide (knee to ankle). Blood flow rates were obtained from compressed tissues with normal vasomotor tone, at papaverine‐induced vasoparalysis and during distension of the compressed vessels. The latter was achieved by inflating a proximal (extra) compression cuff on the thigh 10 or 20 mmHg above the pressure level in the more distally placed compression cuff. Increased tissue pressure was a potent stimulus for arteriolar dilatation (autoregulation) in both tissues. The autoregulatory response was to some extent counteracted by an increase in local vascular resistance in the postcapillary section as evidenced by the results of simultaneous venous stasis. Blood flow ceased in vasoparalysed tissues as well as in tissues with normal vasomotor tone, when the compression cuff was inflated to the level of the local diastolic blood pressure. Maintaining external compression at the diastolic blood pressure level, blood flow reappeared in both tissues, when the compressed vessels were distended by adding the proximal (extra) compression. It is concluded, that blood flow cessation in compressed tissues is caused by a widespread arterial‐arteriolar collapse in diastole, as the volume of blood injected during the systolic peak is too small to expand also the distal sections of the precapillary ve

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07335.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

This study aimed at comparing the effects of running and swimming training protocols and the termination of training on the activities of two proteases with alkaline pH‐optima (alkaline protease and myofibrillar protease) in the tibialis anterior, soleus, and gastrocnemius muscles of male rats. The training on treadmill decreased the activities of alkaline and myofibrillar proteases by approx.10–20% in the muscles studied. The activities of both proteases were unchanged in swimming‐trained rats. Two weeks after the termination of running training the activity of alkaline protease was increased in gastrocnemius muscle but not in the other muscles. Swimming training increased the activity of citrate synthase in all muscles studied but training by running only in the soleus muscle. The running protocol increased the activity of β‐glucuronidase in the tibialis anterior muscle and decreased the activity in the gastrocnemius muscle. The swimming program did not affect β‐glucuronidase activities. These results show diverse effects of running and swimming trainings on alkaline proteolytic activities as well as on mitochondrial and lysosomal mar

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07336.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Microneurography and intraneural microstimulation were employed in awake human subjects to study the characteristics of cutaneous mechanoreceptive units and the sensations mediated by them. 172 units innervating the hand and forearm were identified as either PC, RA (FA in hairy skin), SA I or SA II. Analysis of action potential waveforms in a sample of units suggests that most recordings were from within the myelin sheath. Receptive fields of RA and SA I units were significantly smaller than those of PC and SA II units and showed a proximodistal size gradient, which the latter two did not. The quality of sensations evoked by intraneural stimulation was determined by the type of unit activated, except in the case of SA II units, and their magnitude could be influenced by mechanical coactivation of other sensory units. As a rule projected fields of evoked sensations were larger the further away they were from the limb tip. This grading indicates that inputs from single mechanoreceptive units are processed differently according to their source and sensory submodality, possibly as a result of unequal “resolving powers” of the corresponding cortical neur

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07337.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The accuracy of the cerebral localisation function from the input of single mechanoreceptive units was studied in the hand and forearm of human subjects by means of microneurography and intraneural microstimulation (INMS). The mean distance separating the projected field of a sensation evoked by INMS at liminal amplitude from the receptive field of the activated unit (interfield distance, or IFD) was found to vary from 2.6 mm for SA I units in the fingertips to 23.4 mm for SA I units in the forearm. A less pronounced proximodistal IFD gradient was found for quickly adapting units. IFD values for each skin region were comparable with those obtained by a point localisation test directly on the skin. This indicates that functional gradients exist for inputs from single mechanoreceptive units, and that stimulus localisation hardly improves when numerous units are coactivated.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1983.tb07338.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY