摘要:

AbstractIn the normally innervated rat bladder methacholine, acetylcholine, adrenaline and phenylephrine elicited contraction of the detrusor musclein situ,while isoprenaline caused relaxation. The response to noradrenaline varied but was most often relaxation. Experiments with dihydroergotamine and propranolol indicated the presence of both excitatory a‐receptors and inhibitory β‐receptors in the detrusor muscle. The bladder developed supersensitivity to parasympathomimetic agents and in the case of a‐receptor mediated effects also to sympathomimetic agents after parasympathetic decentralization and denervation, and after sympathetic denervation. Regarding the adrenergic β‐receptor effects, however, no supersensitivity developed after any of the denervation procedures. Parasympathetic denervation or decentralization uncovered a contractile response to noradrenaline most often masked by predominant relaxation in the norma

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05685.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe location of the segmental relays of group II afferents in the spinal cord was investigated by recording extracellular “focal synaptic potentials” (FSP), generated by group II afferents in the gastrocnemius‐soleus nerve. Three types of group II FSPs were differentiated by their location and latency. (1) The “dorsal group II FSP” was located in the dorsal horn dorsolateral to the intermediate nucleus. Its short latency from the incoming group II volley (0.6‐1.0 ins; led to the conclusion that at least the onset is monosynaptically generated. (2) The “ventral group II FSP” was found between the intermediate nucleus and the motor nucleus. This type of FSP had a longer central latency ranging from 1.2‐2.5 ms, which made it difficult to decide whether the linkage was monosynaptic or disynaptic. However, when considering other results (Fu and Schomburg 1974) it seems probable that the ventral FSPs in the low range of central latencies were generated monosynaptically. (3) The “late group II FSP” had a long and varying central latency and was found over a wider region although less regularly than the other FSPs. Presumably the late FSP represents the postsynaptic effect in second and third order neurones. It seems likely that at least the main part of the investigated dorsal and ventral group II FSPs was generated by secondary afferents

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05686.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe intraspinal projection of functionally identified secondary muscle spindle afferents from tenuissimus and medial gastrocnemius was investigated in anesthetized cats. Centrally and peripherally intact single fibres were recorded in the L7 dorsal root. The spinal projection of their axonal branches was traced out by antidromic intraspinal microstimulation (lowest threshold 1.6‐6.0 μA). Collaterals of the investigated fibres were found not only in the dorsal funiculus, the dorsal horn and the intermediate region, but also in the ventral horn close to the motor nucleus or even reaching into it. These findings in conjunction with the results regarding group II focal synaptic potentials (Fuet al. 1974) suggest the existence of two main populations of first order interneurones activated from secondary spindle afferents located in the dorsal and ventral horn, respectively. The central delay of the antidromically conducted group II impulses indicated a substantial reduction of their effective conduction velocity within the spinal co

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05687.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe tissue distribution of125,I‐oxytocin was studied shortly after injection of 40 mU into male rats. There appeared to be a gradual accumulation of radioactivity in the neurohypophysis, and a specific uptake was observed in the vas deferens. The radioactivity content was also studied in extracts prepared from the hypophysis in animals killed 30 or 240 s after injection. There appears to be a very rapid catabolism both in the neuro‐ and adenohypophysis, since radioactivity was found in several substances already 30 s after injection of intact hormone. The uptake pattern in the various tissues is discussed in relation to known or suggested functions of oxytocin in the m

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05688.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractHistamine release in aerobic medium from rat peritoneal mast cells by anaphylactic reaction, dextran and compound 48/80 was associated with a stimulation of exogenous glucose metabolism as determined by carbon dioxide and lactate production. There was generally a correlation between the amount of histamine released and the degree of metabolic stimulation. In anaerobic medium a stimulation of lactate production was observed in most of the experiments when histamine was released by anaphylactic reaction and dextran. Compound 48/80‐induced histamine release in presence of oligomycin was not, however, associated with any appreciable change in lactate production. Galactose and fructose were metabolized by rat mast cells to CO2 and lactate, but the rate of CO2 production was only 18 % and 29%,respectively, and that of lactate production (aerobic) 5 % and 3.6 %, respectively, as compared to the metabolism of glucose to these products under the same conditions. 80 mM galactose could partially reverse the cyanide inhibition of histamine release while the same concentration of fructose was ineffectiv

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05689.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractProtein concentration and colloid osmotic pressure (COP) were estimated in the fluid contained in nylon wicks after implantation in skeletal muscle of rats for 1 to 3 h. After 1 and 2 h implantation wick fluid showed an albumin/total protein ratio of 0.44, compared to 0.61 in plasma. Average concentrations relative to that of plasma were 0.37 for albumin, 0.52 for total protein, and 0.76 (calculated by difference) for non‐albumin protein. After 3 h implantation these ratios had increased significantly to 0.49, 0.69 and 1.07 respectively, presumably indicating beginning inflammation. The unexpected “excess” of non‐albumin wick fluid protein had an electrophoretic mobility like that of plasma β‐globulins, but its origin,‐from plasma or muscle‐is uncertain. Wick fluid COP averaged 8.7 mm Hg, as compared to a plasma COP

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05690.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractIn female spontaneously hypertensive rats, 8–12 months old and consequently with considerable structural changes in their resistance vessels, the aorta was ligated below the renal arteries, markedly lowering the hindquarter blood pressure. 3, 7, 14, 21 and 135 days later the hindquarters of these rats and of control rats were subject to paired perfusions, from maximal dilatation up to maximal pressor responses, thus exploring hemodynamically the rate and extent of regressive changes in vascular design. ‐ Already after 3 days clear signs of regression of the hypertensive vascular changes were found and in about 3 weeks the resistance vessels had almost completed their considerable adjustment to the low pressure situation, with widened lumina and a reduced bulk of contractile media. However, still after another 17 weeks they displayed signs of a wall /lumen ratio elevation compared with the situation in similarly treated young SHR (Folkowet al. 1971 a). ‐ It is concluded that even though a considerable hypotensive readjustment of vascular design takes place also in adult SHR with established hypertension, it is generally more difficult to induce full regression the higher the age and the longer the duration of the disease, presumably due to the gradual addition of less reversible vascular changes such as collagen invasion of the

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05691.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe discharge pattern and recruitment order of single motor units in voluntary contraction of the normal human anterior tibial muscle was studied with an electrode having a high selectivity and a high positional stability in the muscle. In sustained contractions each motor unit was activated at a characteristic level of tension. The higher the threshold of the motor unit in sustained contraction, the higher was the frequency when the unit attained a discharge at regular intervals and the higher tended the “maximum frequency‘‐of the unit to be. Motor units with low thresholds in sustained contractions exhibited a continuous or tonic discharge in strong sustained contractions, whereas units with high thresholds tended to exhibit a discontinuous or phasic discharge. For some units the threshold of activation remained stable, for others it increased during activity. In twitch contractions the recruitment order of motor units differed considerably from that in sustained contrac

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05692.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe question, if muscles can absorb and temporarily store mechanical energy in the form of elastic energy for later re‐use, was studied by having subjects perform maximal vertical jumps on a registering force‐platform. The jumps were performed 1) from a semi‐squatting position, 2) after a natural counter‐movement from a standing position, or 3) in continuation of jumps down from heights of 0.23, 0.40, or 0.69 m. The heights of the jumps were calculated from the registered flight times. The maximum energy level, Eneg, of the jumpers prior to the upward movement in the jump, was considered to be zero in condition 1. In condition 2 it was calculated from the force‐time record of the force‐platform; and in condition 3 it was calculated from the height of the downward jump and the weight of the subject. The maximum energy level after take‐off, Ep0s, was calculated from the height of the jump and the jumper's weight. It was found that the height of the jump and Epos increased with increasing amounts of Eneg, up to a certain level (jumping down from 0.40 m). The gains in Eposover that in condition 1, were expressed as a percentage of Enegand found to be 22.9 % in condition 2, and 13.2, 10.5, and 3.3 % in the three situations of condition 3. It is suggested that the elastic energy is stored in the active muscles, and it is demonstrated that the muscles of the legs are activated in the downward jumps before contact with the platform i

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05693.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThree age groups of SHR were treated orally with hydralazine and guanethidine. The first “prehypertensive” group was treated from 2.5 until 8 months of age, and thereafter pressure was followed for another 6 months. A delayed and quite modest pressure increase then occurred and average life span was prolonged compared with untreated SHR or SHR treated only from 12 months of age. ‐ The second, 8 months old group, representing “established” hypertension, was treated for 5, 10 or 20 weeks, the last subgroup being followed for another 2 weeks without treatment. Arterial pressure, left ventricular weight and design of the resistance vessels as explored by quantitative hemodynamic analyses, were studied at these intervals. After 5 weeks pressure was normalized with some regression of hypertrophic vascular changes, particularly in females, though the increased wall/lumen ratio appeared to remain and heart weight was only slightly reduced. After 20 weeks with and 2 weeks without treatment, cardiac and vascular design were still the same as during treatment but pressure had now risen considerably. ‐ The third, 14 months old group with “advanced” hypertension was treated for 13 weeks, causing only modest pressure reduction and vascular regression. ‐ This suggests that early treatment has great advantages, that females exhibit more regression of vascular structural changes than males and that late treatment gives less regression, presumably due to addition of less reversible wall compone

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1974.tb05694.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY