Wiley

The behaviour of noradrenaline (NA) in double ligated rat and cat sciatic nerves was studied histo‐chemically, using the fluorescence method of Hillarp and coworkers, and biochemically using the trihydroxyindole method. It was found that a large amount of the NA in thc nerve betwcen the two ligations was transported down to the part just above the low ligation. By both method:; it was shown that during the first hours after the ligation the course of accumulation of NA in the nerve just proximal to the low ligation was about the same as the accumulation curve for the nerve (connected to the cell bodies) above the high ligature. Thereafter no further changes were found to occur in the nerve between the constrictions, whereas in the part above the high ligature the accumulation of NA continued as described earlier. The total NA content in the nerve between the two ligatures did not exceed the amount of a normal nerve of the same length. It was concluded that the transport mechanism in the adrenergic fibres is mainly independent of the cell hody (and the nerve terminals) and that no increase in the NA content in the axons occurs after a ligation of the nerve. Furthermore, the present study gives support to the earlier obtained data for the transport of amine granules in the sciatic nerve of rat and cat.

Electronmicroscopical studies of the rat ileum have demonstrated the presence of submucosal neuronlike cells located just under the basal lamina of intestinal crypts. These cells had dendrite‐like processes and frequently made contacts with adjacent submucosal nerve terminals. Furthermore, within the mucosa epithelial ‘clear’ cells with apical cytoplasmic processes into the gut lumen and basal cytoplasmic processes extending underneath adjacent epithelial cells were demonstrated. The ‘clear’ cells were devoid of secretory granules, as e.g. endocrine cells. and had a morphological resembiance to taste cells. Occasionally the ‘clear’ cells made contacts with submucosal nerve tcrminals. The possibility that the ‘clear’ cells and submucosal neuronlike cells represent a receptive function within the intestine is discussed.

Previous results (MacRobbie & Ussing 1961) in combination with published values for cellular chloride concentration and for intracellular potentials show that the chloride concentration in frog skin epithelium cells is higher than predicted for equilibrium with the inside bathing solution. Both the apical and the basolateral membrane of these cells are normally almost tight to chloride, so that the maintenance of the high chloride concentration requires little work. A basolateral permeability to chloride is, however, activated by cell swelling, and the cells lose KCI. It is now shown that the KCI thus lost cannot be regained neither in the absence of sodium in the inside bath nor in the presence of furosemide. The volume regulation reactions are, however, independent of the composition of the outside bath. It is concluded that the recovery of KCI by the epithelium is due to a basolateral co‐transport of NaCl from medium to cells, combined with return of Na to the medium via the Na‐K pump. The co‐transport mechansism thus restores the high chloride concentration of the cells, but seems to be virtually dormant unless the cells have lost chloride.

The osmotic behaviour of the skin epithelium of the brown frog (R. temp.) has been investigated by microscopic measurement of thickness under different experimental conditions. Simultaneous measurements of skin potential and short‐circuit current were made. Epithelial swelling was induced by hypotonicity of the inside but not the outside bathing solution, whereas shrinkage was brought about by hypertonicity of either inside or outside bathing solutions, although the tonicity of the inside bathing solution dominates the osmotic reponse. Shrinkage can also be induced by lowering the potassium concentration of the inside solution. Complex shrinkage and swelling reactions are produced by addition of diffusible substances like urea to either bathing solution. In practically every instance shrinkage leads to inhibition of the short‐circuit current (and thus of the active sodium transport), whereas swelling of the epithelium gives rise to increased active sodium transport. The skin potential is related to swelling and shrinkage in a more involved fashion. In general hypertonicity of the outside bathing solution leads to a violent drop in skin potential. The observations indicate that hypertonicity of the outside solution increases the permeability of the outer epithelial boundary to passively diffusing electrolytes and to water.

On two subjects it is shown, that voluntary hyperventilation in atmospheric air brings about distinct electrocardiographic signs of myocardial hypoxaemia when the carbon dioxide tension in the alveolar air, and therefore also in the arterial blood, is reduced to about 20 mm Hg. It is pointed out that these findings may be of practical importance for the diagnosis of coronary insufficiency by the aid of electrocardiographic tracings after muscular work, or during respiration of a mixture of air poor in oxygen and carbon dioxide free, as these methods may cause an involuntary hyperventilation, and by this, a reduction of the carbon dioxide tension in the arterial blood.

Finally it is pointed out that these results argue in favour of using the hypoxaemia test and not the working electrocardiogram for the diagnosis of latent coronary insufficiency, and of using for the hypoxaemia test a mixture of air containing 2 or 3 per cent carbon dioxide in order to counteract the acapnia brought about by the hyperventilation.

Bài viết mô tả một phương pháp kiểm nghiệm hóa học cho một lượng nhỏ adrenaline và noradrenaline trong các mô. Các catecholamin được chiết xuất bằng axit perchloric. Các chiết xuất được đưa qua cột trao đổi cation (Dowex 50) nhằm hấp thụ catecholamin. Việc tách các amin khỏi cột được thực hiện bằng axit hydrochloric. Sự ước lượng của hai amin trong các dung dịch lọc được thực hiện thông qua phương pháp huỳnh quang sau khi thực hiện quá trình oxy hóa và tái cấu trúc trong kiềm. Phân biệt giữa adrenaline và noradrenaline được thực hiện bằng cách sử dụng sự khác biệt trong quang phổ kích hoạt của các chất gây huỳnh quang.