scholarly journals Calcium and Facilitation at Two Classes of Crustacean Neuromuscular Synapses

1973 ◽  
Vol 61 (1) ◽  
pp. 56-73 ◽  
Author(s):  
Thomas M. Linder
Keyword(s):  
Action Potential ◽  
Transmitter Release ◽  
Conditioning Stimulus ◽  
Critical Factor ◽  
The Other ◽  
Double Logarithmic Plot ◽  
Neuromuscular Synapses ◽  
Logarithmic Plot ◽  
Synaptic Region ◽  
The Relationship

The closer muscle of the crab, Chionoecetes, has at least two classes of excitatory neuromuscular synapses. In one class of synapses an action potential depolarizing the synaptic region releases much more transmitter if it has been preceded recently by another action potential. The other class of synapses shows this property, called facilitation, to a far lesser extent. Immediately after one conditioning stimulus the level of facilitation is similar in both classes. The rate of the ensuing decay of the facilitation is the critical factor differentiating the two classes of synapses. The relationship between external Ca++ concentration and transmitter release is similar for both classes of synapses. The slope of a double logarithmic plot of this relationship varies from 3.1 between 5 and 10 mM Ca++ to 0.9 between 30 and 40 mM Ca++. Facilitation does not significantly change when tested in external Ca++ concentrations ranging from 7 to 30 mM. The extracellularly recorded nerve terminal action potential does not increase in amplitude during facilitation. The results suggest that the mechanism of synaptic facilitation is similar for both classes of synapses and occurs after the stage in transmitter release involving Ca++.

Intraterminal Ca2+ and Spontaneous Transmitter Release at the Frog Neuromuscular Junction

2001 ◽  
Vol 85 (1) ◽  
pp. 287-294 ◽  
Author(s):  
J. K. Angleson ◽  
W. J. Betz
Keyword(s):  
Neuromuscular Junction ◽  
Phorbol Ester ◽  
Intracellular Recording ◽  
Transmitter Release ◽  
The Other ◽  
Nerve Terminals ◽  
Frog Neuromuscular Junction ◽  
Tetraacetic Acid ◽  
Ratiometric Imaging ◽  
The Relationship

We investigated the relationship between intraterminal Ca2+concentration ([Ca2+]i) and the frequency of miniature end plate potentials (MEPPs) at the frog neuromuscular junction by use of ratiometric imaging of fura-2-loaded nerve terminals and intracellular recording of MEPPs. Elevation of extracellular [KCl] over the range of 2–20 mM resulted in increases in [Ca2+]i and MEPP frequency. Loading terminals with the fast and slow Ca2+-buffers bis-( o-aminophenoxy)- N,N,N′,N′-tetraacetic acid-acetoxymethyl (BAPTA-AM) and EGTA-AM resulted in equivalent reductions in the KCl-dependent increases in MEPP frequency. The [Ca2+]i dependence of MEPP frequency determined by elevation of [Ca2+]i due to application of 0.1–10 μM ionomycin was similar to that determined when [Ca2+]i was raised by increasing extracellular KCl. Measurements in 10 mM extracellular KCl revealed that application of the phorbol ester phorbol 12 myristate 13-acetetate (PMA) caused an increase in MEPP frequency while the inactive analogue, 4α-PMA, did not. PMA application also caused an increase in [Ca2+]i. The relationship between [Ca2+]i and MEPP frequency in PMA was the same as was determined by the other methods of raising [Ca2+]i. Under all conditions tested, our data revealed a low [Ca2+]i threshold for activation of transmitter release and are consistent with a K d for [Ca2+]i on the order of 1 μM.

A simulation of action potentials in synaptic boutons during presynaptic inhibition

1994 ◽  
Vol 71 (2) ◽  
pp. 538-549 ◽  
Author(s):  
B. Graham ◽  
S. Redman
Keyword(s):  
Action Potential ◽  
Transmitter Release ◽  
Action Potentials ◽  
Presynaptic Inhibition ◽  
Chloride Conductance ◽  
Membrane Properties ◽  
Published Data ◽  
Myelinated Nerve ◽  
Synaptic Boutons ◽  
The Relationship

1. During presynaptic inhibition, an increased conductance in the membrane of the presynaptic bouton is presumed to reduce the action potential, thereby reducing transmitter release. The object of the simulation has been to determine the magnitude of a chloride conductance required to reduce transmitter release, for various diameters of synaptic boutons, connected to axons with diameters in the range 0.1-1.0 microns. 2. A propagating action potential was simulated in axons connected to either side of a hemispherical bouton. The axons could be myelinated or unmyelinated, while the bouton membrane could be passive, a node of the myelinated nerve, or have the same active properties as the attached unmyelinated nerve. Membrane properties of the axons were derived from mammalian data and scaled to 37 degrees C. 3. A steady-state chloride conductance was included in the bouton membrane, with ECl = -40 mV. The amplitude of the action potential in the bouton was calculated for different diameters of axon and bouton and for different magnitudes of chloride conductance. 4. Using published data on the relationship between the amplitude of a presynaptic action potential and the resulting postsynaptic potential, the relationship between the chloride conductance and the postsynaptic response was calculated for different geometries. Transmitter release was reduced when an action potential was 90 mV or smaller, with no transmission for action potentials smaller than 50 mV. 5. Conductance increases in the range 3 to 10 nS were required to reduce the action potential to 90 mV, depending on the diameter of the axon (0.5-1.0 microns), diameter of the bouton (3-6 microns), whether the bouton had passive or active membrane, and whether the axon was myelinated or unmyelinated. A 3 microns passive bouton connected to a 0.5 micron myelinated axon was most sensitive to the effects of a chloride conductance, while a 6 microns active bouton connected to a 1 micron myelinated nerve was least sensitive to the effects of a chloride conductance. 6. The reduction in the action potential was compared when ECl = -40 mV and when ECl = E(rest) = -80 mV. Inactivation of the sodium conductance by terminal depolarization was the dominant influence on the amplitude of the action potential. 7. Conductances that were sufficient to completely block synaptic transmission at a bouton were insufficient to prevent the spread of the action potential away from that bouton.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Γονικότητα και διδυμία: Μία διπλή πρόκληση

2020 ◽  
Vol 18 (3) ◽  
pp. 381
Author(s):  
Μαρία Μαρκοδημητράκη
Keyword(s):  
Transition To Parenthood ◽  
Developmental Process ◽  
Critical Factor ◽  
The Other ◽  
Prenatal Period ◽  
Other Hand ◽  
The Subject ◽  
The One ◽  
The Relationship

Ιn the present paper the transition to parenthood of twins and the developmental process of the relationship between parents and their twins from the prenatal period up to adolescence are described and discussed. Our interest is focused on the distinctiveness of this relationship and the issues arising in every developmental step of twins. It is a double challenge for parents. On the one hand they should respond effectively to their role as parents and on the other hand they should simultaneously face the needs of two different children, with all the difficulties involved. In the present work the significance of the twins’ differentiation by their parents while they are still in the prenatal period, is emphasized as it is an important issue for the prevention of comparison, tension or jealousy that are harmful to the twin bond. The realisation that every twin child is different brings out the developmental advantages of twinship (companionship, empathy, cooperation etc) and diminishes the stereotypical view summarized in the phrase “for problem see twin”, which is being questioned by contemporarynaturalistic studies on the subject. Identifying the developmental advantages of twinship is a critical factor for the growth of emotionally healthy twins who respect and appreciate themselves and their relationship.

The Relationship Between Suicidal Thinking and Dating Violence in a Sample of Adolescent Abortion Patients

Crisis ◽  
2011 ◽  
Vol 32 (5) ◽  
pp. 246-253 ◽  
Author(s):  
Gretchen E. Ely ◽  
William R. Nugent ◽  
Julie Cerel ◽  
Mholi Vimbba
Keyword(s):  
Unintended Pregnancy ◽  
Dating Violence ◽  
Young Women ◽  
Psychosocial Problems ◽  
The Other ◽  
Assessment Scale ◽  
Adolescent Dating Violence ◽  
Adolescent Relationships ◽  
Suicidal Thinking ◽  
The Relationship

Background: The relationship between suicidal thinking and adolescent dating violence has not been previously explored in a sample of adolescent abortion patients. Aims: This paper highlights a study where the relationship between dating violence and severity of suicidal thinking was examined in a sample of 120 young women ages 14–21 seeking to terminate an unintended pregnancy. Methods: The Multidimensional Adolescent Assessment Scale and the Conflict in Adolescent Relationships Scale was used to gather information about psychosocial problems and dating violence so that the relationship between the two problems could be examined, while controlling for the other psychosocial problems. Results: The results suggest that dating violence was related to severity of suicidal thinking, and that the magnitude of this relationship was moderated by the severity of problems with aggression. Conclusions: Specifically, as the severity of participant’s general problems with aggression increased, the magnitude of the relationship between dating violence and severity of suicidal thinking increased. Limitations of the study and implications for practice are discussed.

Emotional Impact Feedback Changes How We Remember Negative Autobiographical Experiences

2010 ◽  
Vol 57 (5) ◽  
pp. 354-359 ◽  
Author(s):  
Melanie K. T. Takarangi ◽  
Deryn Strange
Keyword(s):  
Well Being ◽  
The Other ◽  
Personal Perspective ◽  
Emotional Impact ◽  
Potential Mechanism ◽  
Negative Experiences ◽  
Negative Memory ◽  
The Relationship ◽  
Negative Memories ◽  
Over Time

When people are told that their negative memories are worse than other people’s, do they later remember those events differently? We asked participants to recall a recent negative memory then, 24 h later, we gave some participants feedback about the emotional impact of their event – stating it was more or less negative compared to other people’s experiences. One week later, participants recalled the event again. We predicted that if feedback affected how participants remembered their negative experiences, their ratings of the memory’s characteristics should change over time. That is, when participants are told that their negative event is extremely negative, their memories should be more vivid, recollected strongly, and remembered from a personal perspective, compared to participants in the other conditions. Our results provide support for this hypothesis. We suggest that external feedback might be a potential mechanism in the relationship between negative memories and psychological well-being.

Haematocrit: Relationships with Blood Lipids, Blood Pressure and other Cardiovascular Risk Factors

1994 ◽  
Vol 72 (01) ◽  
pp. 058-064 ◽  
Author(s):  
Goya Wannamethee ◽  
A Gerald Shaper
Keyword(s):  
Physical Activity ◽  
Risk Factors ◽  
Blood Pressure ◽  
Body Mass Index ◽  
Cardiovascular Risk ◽  
Cardiovascular Risk Factors ◽  
Alcohol Intake ◽  
Blood Lipids ◽  
The Other ◽  
The Relationship

SummaryThe relationship between haematocrit and cardiovascular risk factors, particularly blood pressure and blood lipids, has been examined in detail in a large prospective study of 7735 middle-aged men drawn from general practices in 24 British towns. The analyses are restricted to the 5494 men free of any evidence of ischaemic heart disease at screening.Smoking, body mass index, physical activity, alcohol intake and lung function (FEV1) were factors strongly associated with haematocrit levels independent of each other. Age showed a significant but small independent association with haematocrit. Non-manual workers had slightly higher haematocrit levels than manual workers; this difference increased considerably and became significant after adjustment for the other risk factors. Diabetics showed significantly lower levels of haematocrit than non-diabetics. In the univariate analysis, haematocrit was significantly associated with total serum protein (r = 0*18), cholesterol (r = 0.16), triglyceride (r = 0.15), diastolic blood pressure (r = 0.17) and heart rate (r = 0.14); all at p <0.0001. A weaker but significant association was seen with systolic blood pressure (r = 0.09, p <0.001). These relationships remained significant even after adjustment for age, smoking, body mass index, physical activity, alcohol intake, lung function, presence of diabetes, social class and for each of the other biological variables; the relationship with systolic blood pressure was considerably weakened. No association was seen with blood glucose and HDL-cholesterol. This study has shown significant associations between several lifestyle characteristics and the haematocrit and supports the findings of a significant relationship between the haematocrit and blood lipids and blood pressure. It emphasises the role of the haematocrit in assessing the risk of ischaemic heart disease and stroke in individuals, and the need to take haematocrit levels into account in determining the importance of other cardiovascular risk factors.

Structuralism as a Pamphlet (On the Book by E. Reinert “How Rich CountriesGot Rich... And Why Poor Countries Stay Poor”. 2nd ed.)

2014 ◽  
pp. 147-153
Author(s):  
P. Orekhovsky
Keyword(s):  
Economic Theory ◽  
Economic Development ◽  
Structural Analysis ◽  
Increasing Returns ◽  
The Other ◽  
Static Theory ◽  
Poor Countries ◽  
Historical School ◽  
Socio Economic Development ◽  
The Relationship

The review outlines the connection between E. Reinert’s book and the tradition of structural analysis. The latter allows for the heterogeneity of industries and sectors of the economy, as well as for the effects of increasing and decreasing returns. Unlike the static theory of international trade inherited from the Ricardian analysis of comparative advantage, this approach helps identify the relationship between trade, production, income and population growth. Reinert rehabilitates the “other canon” of economic theory associated with the mercantilist tradition, F. Liszt and the German historical school, as well as a reconside ration of A. Marshall’s analysis of increasing returns. Empirical illustrations given in the book reveal clear parallels with the path of Russian socio-economic development in the last twenty years.

Dış Göç Romanlarında Temel İzlekler

2020 ◽  
Vol 7 (2) ◽  
pp. 291-317
Author(s):  
Burak Çavuş
Keyword(s):  
The Other ◽  
Guest Worker ◽  
Migration Literature ◽  
Historical Reality ◽  
Literary Process ◽  
The Relationship

Bu çalışmada, 1960-1990 yılları arasında yayınlanan ve Avrupa’ya işçi göçünü konu edinen romanlar izleksel bağlamda incelenmiştir. Romanlardaki temel izlekler çerçevesinde göç süreci irdelenmiş, inceleme, göçmenlerin tanımlanmasında ve adlandırılmasında kullanılan Gastarbeiter (konuk işçi) Auslander (yabancı) kavramları ve Almanlar tarafından Türk kimliğine atfedilen çağrışımlar üzerinden yürütülmüştür. Göçmenlere yönelik politikalarda ve yaklaşımlarda onların nasıl tanımlandığının etkili olduğuna ve yazınsal süreçte de bu politika ve yaklaşımların belirleyici olduğu savından hareket edilmiştir. Bu noktada adlandırmaların, tanımlamaların göç olayı çerçevesinde biz ve öteki ilişkisi üzerindeki etkisine odaklanılmış; toplum ve yazın ilişkisi temelinde incelenen romanlar üzerinden göç ve göçmenlik meselesine dair çıkarımlar yapılmıştır. Bunlar arasında, ayrımcılık, kötü çalışma koşulları, hak ihlalleri, ırkçılık ve ötekileştirme gibi başat sorunların bu eserlerde merkezi konumda olduğu tespit edilmiştir. Böylece çalışmanın amacı olan göç yazınını oluşturan temel izleklere ulaşılmış; sosyolojik ve tarihsel gerçekliğin yazınsal gerçekliğe aktarılmasında etkili olan unsurlar ön plana çıkarılmıştır. ABSTRACT IN ENGLISH Main Patterns in Migration Novels In this study, the novels published between 1960-1990 and dealing with the migration of workers to Europe were examined in a contextual context. The process of immigration has been examined within the framework of the basic lines in the novels, through the concepts of Gastarbeiter (guest worker), Auslander (foreigner) used in the identification and naming of immigrants and connotations attributed to Turkish identity was conducted. The argument is that how they are defined is effective in policies and approaches towards immigrants and that these policies and approaches are determinative in the literary process. At this point, the effect of naming definitions on us and the other relationship within the framework of migration has been focused; there are inferences about the issue of migration and immigration through the novels examined on the basis of the relationship between society and literature. Among these, it has been determined that dominant problems such as discrimination, poor working violations, racism and marginalization are central to these works. Thus, the basic themes that constitute the migration literature, which is the aim of the study have been reached and the factors that are effective in transferring the sociological and historical reality have been brought the fore.

“I’ve got you under my skin”: borderline states in couple relationships

2020 ◽  
Vol 10 (1) ◽  
pp. 59-71
Author(s):  
Perrine Moran
Keyword(s):  
The Other ◽  
Couple Relationships ◽  
Early Stages ◽  
Popular Songs ◽  
The Relationship

Many couples who come for therapy are struggling with separating from unconscious phantasies and beliefs that enmesh each partner with the other, resulting in states that popular songs powerfully epitomise. While this borderline experience is common and functional in the early stages of being in love its persistence paralyses the development of the relationship. Facing separation from and loss of illusion is a challenge couple therapists are often asked to help with. The argument is illustrated by a case, and by references to some of Cole Porter’s best known songs.

From Container to Claustrum: Projective Identification in Couples

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Tamara Feldman
Keyword(s):  
Psychological Health ◽  
Projective Identification ◽  
The Self ◽  
The Other ◽  
Intimate Partners ◽  
And Control ◽  
The Relationship ◽  
As If

This paper is a contribution to the growing literature on the role of projective identification in understanding couples' dynamics. Projective identification as a defence is well suited to couples, as intimate partners provide an ideal location to deposit unwanted parts of the self. This paper illustrates how projective identification functions differently depending on the psychological health of the couple. It elucidates how healthier couples use projective identification more as a form of communication, whereas disturbed couples are inclined to employ it to invade and control the other, as captured by Meltzer's concept of "intrusive identification". These different uses of projective identification affect couples' capacities to provide what Bion called "containment". In disturbed couples, partners serve as what Meltzer termed "claustrums" whereby projections are not contained, but imprisoned or entombed in the other. Applying the concept of claustrum helps illuminate common feelings these couples express, such as feeling suffocated, stifled, trapped, held hostage, or feeling as if the relationship is killing them. Finally, this paper presents treatment challenges in working with more disturbed couples.

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