ADAPTATION OF CUTANEOUS TACTILE RECEPTORS. III

Further experimental evidence is presented indicating that the peripheral inhibitory phenomenon known as sensory adaptation, as it is manifested in tactile receptors in frogs'' skin, is produced by a neurohumor released by non-nervous cells of the skin when they are pressed upon. 1. Adaptation is not produced by electrically initiated antidromic impulses backfired into the axon branches. 2. Intermittent air jet stimulation of a region of skin several millimeters distant from a responsive single ending produces failure of response of the ending to a similar direct intermittent stimulus applied to the skin containing the ending immediately afterward. 3. Constant pressure causes an ending to adapt but no spread of the effect, as described in the above paragraph, is found. This implies that the spread is the result of the vibratory movement of the skin. 4. The time curves of recovery from adaptation are inconsistent with any known properties of isolated nerve.     

ADAPTATION OF CUTANEOUS TACTILE RECEPTORS. II

Studies of axon potentials set up by pressure stimuli applied to single cutaneous receptors in frog''s skin indicate that the mechanical stimulus excites the free nerve endings directly. Adaptation to constant pressures or to intermittently applied pressures (failure of the response) may be due to the reduction of excitability of the nerve endings by potassium released under the pressure from surrounding epithelial cells.     

ADAPTATION OF CUTANEOUS TACTILE RECEPTORS : V. THE RELEASE OF POTASSIUM FROM FROG SKIN BY MECHANICAL STIMULATION

Potassium is released from the epithelial cells of frog''s skin on stimulation by an interrupted air jet. This evidence is consistent with the hypothesis that potassium is involved in the adaptation of the tactile nerve endings in frog''s skin.     

ADAPTATION OF CUTANEOUS TACTILE RECEPTORS : IV. ELECTROLYTE CONTENT OF FROG SKIN

The potassium content of the skin of Rana pipiens is found to be 132 m.g. per cent. This is roughly of the order of magnitude of the content of potassium in nerve. Analyses were also made of the skin for Na, Ca, Mg, Cl, S, and P.     

QUANTITATIVE ASPECTS OF CUTANEOUS SENSORY ADAPTATION. I

1. Adaptation of tactile receptors in the skin of the frog to excitation by an intermittent jet of air is measured and correlated with certain properties of a series of notched discs used to interrupt the air stream. 2. Adaptation in fifteen cases is found to be described by either one of two empirical formulas, or t = -k log f + C, for nine preparations t = a f^-b, for six preparations where f is the per cent frequency at time t and -k and -b are constants defining the rate of adaptation.     

喀斯特地区植物钙含量特征与高钙适应方式分析

喀斯特地区土壤的高钙含量是影响该地区植物生理特征的最重要环境因素之一。高钙影响植物的光合作用、生长速率及磷代谢, 从而限制了许多物种在该地区的分布。选取贵州4个石漠化程度不同的地区, 测定采集地内45种优势种或常见种的地上部分和地下部分的全钙含量以及土壤的交换性钙含量。通过分析喀斯特地区植物与土壤钙含量的特征发现: 喀斯特地区植物具有较高的钙含量平均值; 土壤交换性钙含量对植物地上部分钙含量的影响总体上不显著, 对植物地下部分钙含量的影响显著; 不同类别植物的钙含量存在显著差异, 蕨类植物地上部分钙含量平均值明显低于被子植物; 不同类别植物钙的分布部位也存在显著差异, 在蕨类植物和单子叶植物中地上部分和地下部分的钙含量相近, 而双子叶植物的地上部分钙含量明显高于地下部分。分析了喀斯特地区14种优势灌木和草本植物地上部分与地下部分钙含量的差异性以及与土壤交换性钙含量的相关关系, 以此为根据将14种优势植物对土壤高钙的适应方式分为3种类型: 随遇型、高钙型和低钙型。随遇型植物的钙含量主要受土壤交换性钙含量影响, 其地上部分和地下部分的钙含量均与土壤交换性钙含量成显著正相关关系; 高钙型植物具有较强的钙富集能力, 其地上部分即使在低钙含量的土壤中也可维持较高的钙含量; 低钙型植物的地上部分即使在高钙含量的土壤中亦可维持较低的钙含量。对植物适应钙的不同方式的研究可用于筛选退化生态系统恢复所需的植物资源。     

雌二醇对豚鼠心室肌细胞L型钙通道的抑制作用

目的和方法：采用全细胞膜片钳技术,研究不同浓度（１μｍｏｌ／Ｌ、１０μｍｏｌ／Ｌ、１００μｍｏｌ／Ｌ）雌二醇（ｅｓｔｒａｄｉｏｌ,ＥＳＴ）对豚鼠心室肌细胞Ｌ型钙电流（ＩＣａ．Ｌ）的影响。结果：①ＥＳＴ明显抑制ＩＣａ．Ｌ,１μｍｏｌ／Ｌ、１０μｍｏｌ／Ｌ、１００μｍｏｌ／ＬＥＳＴ分别使峰值ＩＣａ．Ｌ降低３０．５％,５０．０％（Ｐ〈０．０１）和６８％（Ｐ〈０．０１）,该作用具有浓度依赖性;②ＥＳＴ对Ｉ     

SPECIFIC NERVE IMPULSES FROM GUSTATORY AND TACTILE RECEPTORS IN CATFISH

1. Receptors in the lips and barbels of the catfish Ameiurus nebulosus Les. are very sensitive to mechanical stimuli, giving large rapid (A-type) impulses in fibers of the facial nerve in response to touching the receptive surfaces and to movements of the water in which the preparation is immersed. 2. The great sensitivity of the barbels and lips to currents of water and the bilateral symmetry of the distribution of sensitivity of the facial nerve may serve as a basis for observed rheotropic orientation in the catfish. 3. Acetic acid, NaCl, and meat juice, dissolved in the water bathing the barbels and lips, set up impulses of very small and barely detectable potential in the fibers of the facial nerve. 4. It is suggested that the specificity of impulses for the two sense modalities may be correlated with the large size of the cells of origin of the axons in the Gasserian ganglion supplying tactile receptors and the small size of the cells of origin in the geniculate ganglion sending axons to taste-buds.     

REGULATION OF OXYGEN CONSUMPTION IN NEUROBLASTOMA CELLS: EFFECTS OF DIFFERENTIATION AND OF POTASSIUM

Abstract— The rate of oxygen consumption has been measured micromanometrically in fresh mouse neuroblastoma cells and in corresponding cells cultivated with and without 20% calf serum known to suppress differentiation. Fresh cells and cells cultivated in the serum depleted medium showed a relatively intense respiration (0.5–1.0 × 10⁻⁵μl/h/cell), whereas the proliferating, cultivated cells had a low rate of oxygen uptake (0.2 × 10^-5μl/h/cell), provided they did not differentiate morphologically during the 4 h of measurement in the serum-free diver medium. Both morphological and metabolic differentiation of such cells occurs rapidly but may be completely prevented by siliconization of the divers.
An increase of the potassium concentration in the medium to 50 mM had essentially no effect on cultivated, differentiated cells, but led to an abolishment of oxygen uptake by fresh cells. No stimulatory effect of potassium was observed.     

EFFECTS OF TAURODEOXYCHOLATE AND CALCIUM ON CONTRACTILITY OF NEWT EGGS

Injection of taurodeoxycholate (TDOC) alone or in combination with 10⁻⁵ M Ca²⁺(Ca-EGTA buffer) into newt eggs induced a cup- or furrow-like depression on the egg surface. Reduction of the Ca²⁺ concentration inhibited the response. These findings imply that TDOC induces a cytoplasmic contraction associated with the membrane and that a micromolar Ca²⁺ concentration is required for this process. Injection of 10⁻⁵ M Ca²⁺(Ca-EGTA buffer) alone had no effect. On the basis of these findings, the roles of TDOC and Ca²⁺ in induction of contraction were discussed.     

EFFECTS OF GUAIACOL AND HEXYLRESORCINOL IN THE PRESENCE OF BARIUM AND CALCIUM

Guaiacol was applied at two spots on the same cell of Nitella. At one spot it was dissolved in 0.01 M NaCl, at the other in 0.01 M CaCl₂ or BaCl₂. The effect was practically the same in all cases, i.e. a similar change of P.D. in a negative direction, involving a more or less complete loss of P.D. (depolarization). When hexylresorcinol was used in place of guaiacol the result was similar. That Ca⁺⁺ and Ba⁺⁺ do not inhibit the effect of these organic depolarizing substances may be due to a lack of penetration of Ca⁺⁺ and Ba⁺⁺. The organic substances penetrate more rapidly and their effect is chiefly on the inner protoplasmic surface which is the principal seat of the P.D.     

转铁蛋白抑制大鼠卵泡颗粒细胞FSH受体的结合与维持

转铁蛋白能抑制大鼠卵泡颗粒细胞的分化,但其机理尚不清楚。本实验用已烯雌酚处理后分离的大鼠颗粒细胞,观察了转铁蛋白对FSH结合到颗粒细胞,以及在培养过程中对颗粒细胞FSH受体量维持的影响。结果表明,生理浓度范围的转铁蛋白部分地阻断了~(125)I-rFSH结合到颗粒细胞上;将转铁蛋白与FSH一起处理细胞,发现它能剂量依赖性地抑制FSH对颗粒细胞FSH受体的维持作用,并表现为孕酮及雌二醇的分泌减少。     

EFFECTS OF pH AND OF VARIOUS CONCENTRATIONS OF SODIUM,POTASSIUM, AND CALCIUM CHLORIDE ON MUSCULAR ACTIVITY OF THE ISOLATED CROP OF PERIPLANETA AMERICANA (ORTHOPTERA)

1. Twenty-five solutions which contained KCl (0.0, 0.2, 0.4, 0.6, and 0.8 gm. per liter), in combination with CaCl₂ (0.0, 0.2, 0.4, 0.6, and 0.8 gm. per liter), 10.0 gm. of NaCl, and 0.2 gm. of NaHCO₃ per liter of solution were tested in order to determine satisfactory KCl/CaCl₂ ratios in an insect physiological salt mixture for the maintenance of muscular activity by the isolated crop of the American roach. Satisfactory activity products (0.390 to 0.549) were obtained in seven mixtures with KCl/CaCl₂ ratios of 0.2/0.2, 0.4/0.4, 0.6/0.6, 0.8/0.8, 0.2/0.4, 0.4/0.6, and 0.6/0.8, expressed as gram per liter. These ratios lie between 0.50 and 1.00. In solutions which contained calcium, but no potassium, approximately 50 per cent of the crops exhibited an initial tone increase and were arrested in rigor. See Fig. 2. In solutions which contained potassium, but no calcium, all crops showed an initial loss of tone and arrest in relaxation. See Fig. 2. 2. Seven KCl/CaCl₂ ratios (see paragraph 1 above) were tested with eight NaCl concentrations (1.0, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, and 1.8 per cent) at a pH of 8.0. In these mixtures, the ones with KCl/CaCl₂ ratios of less than 1.0 produced higher activity products than those with ratios equal to 1.00. The highest average activity product (0.849) was obtained in the solutions with 0.2 gm. of KCl and 0.4 gm. of CaCl₂ per liter. 3. Four KCl/CaCl₂ ratios (0.2/0.2, 0.4/0.4, 0.2/0.4, and 0.4/0.6 gm. per liter) were tested with 1.4, 1.5, and 1.6 per cent NaCl at a pH of 7.5. When analyzed with data from comparable solutions at a pH of 8.0, it was found that 1.4 per cent NaCl afforded an optimum environment for isolated crop activity. 4. Effects of hydrogen and hydroxyl ion concentrations were studied at pH values of 6.8, 7.5, 8.0, and 8.9. The highest average activity product, 1.011, was produced at a pH of about 8.0. 5. A satisfactory physiological salt solution for the isolated foregut of the American roach, Periplaneta americana, would contain 14.0 gm. of NaCl, 0.4 gm. of CaCl₂, 0.2 gm. of KCl, and 0.2 gm. of NaHCO₃ per liter of solution. This mixture should have a pH value between 7.8 and 8.2. 6. Durations of crop activity extending over periods as long as 25 hours were quite common, and several crops maintained contractions for more than 30 hours. The greatest longevity was for crop 814, from a female, which continued activity for slightly more than 47 hours. 7. A significant difference between the activity products of the crops from males and the crops from females was recorded. Although there was not a significant difference in the amount of food ingested by males and females, 12 hours after feeding there was more food in the females'' crops, and the food progressed more rapidly through the males'' crops than through the females''. In addition, crops from the two sexes reacted differently to the effects of day old solutions. This sex difference is apparently related to an inherently increased activity of the crop from the male roach.     

灯盏花总黄酮对血小板聚集和血栓形成的影响

采用Ｂｏｍ氏比浊法测定灯盏花总黄酮（Ｅｒｉｇｅｒｏｎ ｂｒｅｖｉｓｃａｐｕｓ ｆｌａｖｏｎｅｓ,ＥＢＦ）在体内和体外对血小板活化聚集的影响。应用Ｋｏｈｌｅｒ等法观察ＥＢＦ对小鼠尾静脉注射花生四烯酸（ＡＡ）所致突然死亡的保护作用。结果表明,ＥＢＦ在体外和体内对ＡＤＰ、ＡＡ或血小板活化因子（ＰＡＦ）引起的血小板聚集均有明显抑制作用,体外实验,其效应呈浓度依赖关系,体内试验,于给药后１８０ｍｉｎ达最大抑     

CO-REQUIREMENT FOR CALCIUM AND POTASSIUM IN THE GERMINATION OF SPORES OF THE FERN ONOCLEA SENSIBILIS

Spores of Onoclea sensibilis L. do not germinate on distilled H₂O if they are pretreated for sufficient time with dilute NaClO solution. However, spores will germinate, after NaClO pretreatment, on a simple mineral medium containing the major and trace elements. Complete germination after pretreatment also is obtained on a solution containing only Ca²⁺ and K⁺ as the cations, but neither ion by itself is sufficient. Rb⁺, but not Li⁺ or Na⁺, can replace K⁺. Hypochlorite-treated spores do not require the continuous presence of Ca²⁺ and K⁺ to germinate; exposure during the first 4 hr of culture, with the remainder of the time on distilled H₂O, is sufficient. Extraction of spores with ethylene glycol bis(aminoethyl ether) tetraacetic acid [EGTA] makes their germination dependent on Ca²⁺, as reported by other workers, but it does not produce a co-requirement for K⁺. Colorimetric analysis with arsenazo III confirms that Ca²⁺ is extracted from Onoclea spores by NaClO. Extractable Ca²⁺ amounts to about 78 nmol/mg spore dry wt. Of this amount, 31% is contained in the perispore. The perispore comprises 13% of the total spore dry wt.     

钙对萝卜幼苗抗寒性及某些生理指标的影响

研究结果表明钙能够提高萝卜幼苗的抗寒性, 同时与抗寒性有关某些生理指标也受到影响。在低温胁迫后及恢复生长后处理组的萝卜幼苗的超氧物歧化酶、过氧化物酶、抗坏血酸过氧化物酶、过氧化氢酶的活性都比对照组高;在低温胁迫后处理组的脯氨酸及抗坏血酸的含量均比对照组高, 但处理组萝卜幼苗的丙二醛含量却比对照组低。表明钙对萝卜幼苗抗寒性的影响可能与其防止膜脂过氧化有关。     

ROLE OF CALCIUM IN POTASSIUM UPTAKE BY PLANT ROOTS

The effects of EDTA·Mg or GEDTA·Mg on the uptakeof nutrient ions, the release of Ca⁺⁺ and nucleotides into themedium and the nucleic acid contents in rice and red bean rootswere investigated.

1. Both EDTA and EDTA·Mg induced similarly the release ofCa from roots.
2. EDTA·Mg as well as EDTA brought abouta significant repressionin K uptake, but had an insignificantor no effect on P, NH₄and NO₃ uptakes. EDTA·Ca did notrepress K, P, NH₄ andNO₃ uptakes.
3. EDTA or GEDTA acceleratedthe degradation of nucleic acid andthe release of nucleotides,while EDTA·Mg or GEDTA·Mghad no such effect.

These results indicate that the indispensable role of intracellularCa in K uptake does not appear to be directly associated withRNA metabolism. (Received July 29, 1965; )     

EFFECTS OF POTASSIUM AND GLUTAMATE ON BRAIN CORTEX SLICES: UPTAKE AND RELEASE OF GLUTAMIC AND OTHER AMINO ACIDS

Abstract— Effects of an increased concentration of K⁺ (55 m m ) in the medium on fluxes of glutamate and other amino acids in the presence and absence of 10 m m -glutamate were studied. The following observations were made:
(1) The efflux of glutamate is slightly increased by excess K⁺. The glutamate efflux is smaller than the potassium fluxes.
(2) The K⁺-induced increase of glutamate efflux is enhanced under anoxia or in glutamate-containing media.
(3) The influx of glutamate is unaffected or slightly increased by excess K⁺.
(4) The efflux of GABA is increased by excess K⁺, both in the absence and in the presence of glutamate.
(5) Efflux of glutamine, leucine and lysine is increased by excess K⁺, but only provided that glutamate is also present in the medium.
(6) Efflux of glutamate and of GABA is increased by addition of 10 m m -glutamate.