Effects of Compounds That Influence IK (KCNN4) Channels on Afterhyperpolarizing Potentials, and Determination of IK Channel Sequence, in Guinea Pig Enteric Neurons

The late afterhyperpolarizing potential (AHP) that follows the action potential in intrinsic primary afferent neurons of the gastrointestinal tract has a profound influence on their firing patterns. There has been uncertainty about the identity of the channels that carry the late AHP current, especially in guinea pigs, where the majority of the physiological studies have been made. In the present work, the late AHP was recorded with intracellular microelectrodes from myenteric neurons in the guinea pig small intestine. mRNA was extracted from the ganglia to determine the identity of the guinea pig intermediate conductance potassium ( IK) channel gene transcript. The late AHP was inhibited by two blockers of IK channels, TRAM34 (0.1–1 μM) and clotrimazole (10 μM), and was enhanced by the potentiator of the opening of these channels, DC-EBIO (100 nM). Action potential characteristics were unchanged by TRAM34 or DC-EBIO. The full sequence of the gene transcript and the deduced amino acid sequence were determined from extracts including myenteric ganglia and from bladder urothelium, which is a rich source of IK channel mRNA. This showed that the guinea pig sequence has a high degree of homology with other mammalian sequences but that the guinea pig channel lacks a phosphorylation site that was thought to be critical for channel regulation. It is concluded that the channels that carry the current of the late afterhyperpolarizing potential in guinea pig enteric neurons are IK channels.

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Feasibility of Molecular Structure Determination With a High Resolution Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101438 ◽

1968 ◽

Vol 26 ◽

pp. 338-339

Author(s):

T. A. Welton

Keyword(s):

Electron Microscope ◽

Substrate Surface ◽

Helical Axis ◽

Base Plane ◽

Resolution Electron ◽

High Resolution Electron Microscope ◽

High Degree ◽

Degree Of Order ◽

Purine Pyrimidine

An ultimate design goal for an improved electron microscope, aimed at biological applications, is the determination of the structure of complex bio-molecules. As a prototype of this class of problems, we propose to examine the possibility of reading DNA sequence by an imaginable instrument design. This problem ideally combines absolute importance and relative simplicity, in as much as the problem of enzyme structure seems to be a much more difficult one.The proposed technique involves the deposition on a thin graphite lamina of intact double helical DNA rods. If the structure can be maintained under vacuum conditions, we can then make use of the high degree of order to greatly reduce the work involved in discriminating between the four possible purine-pyrimidine arrangements in each base plane. The phosphorus atoms of the back bone form in projection (the helical axis being necessarily parallel to the substrate surface) two intertwined sinusoids. If these phosphorus atoms have been located up to a certain point on the molecule, we have available excellent information on the orientation of the base plane at that point, and can then locate in projection the key atoms for discrimination of the four alternatives.

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Influence of the Share of Renewable Energy Sources on the Level of Energy Security in EECCA Countries

Energies ◽

10.3390/en14040903 ◽

2021 ◽

Vol 14 (4) ◽

pp. 903 ◽

Cited By ~ 1

Author(s):

Ivan Trifonov ◽

Dmitry Trukhan ◽

Yury Koshlich ◽

Valeriy Prasolov ◽

Beata Ślusarczyk

Keyword(s):

Renewable Energy ◽

Energy Security ◽

Structural Characteristics ◽

Renewable Energy Sources ◽

Energy Resource ◽

Energy Sources ◽

Structural Content ◽

High Degree

In this study we aimed to determine the extent to which changes in the share of renewable energy sources, their structural complex, and the level of energy security in Eastern Europe, Caucasus and Central Asia (EECCA) countries in the medium- and long-term are interconnected. The study was performed through modeling and determination of the structural characteristics of energy security in the countries. The methodology of the approach to modeling was based on solving the problem of nonlinear optimization by selecting a certain scenario. For the study, the data of EECCA countries were used. The ability of EECCA countries to benefit from long-term indirect and induced advantages of the transformation period depends on the extent to which their domestic supply chains facilitate the deployment of energy transformation and induced economic activity. This study provides an opportunity to assess the degree of influence of renewable energy sources on the level of energy security of countries in the context of energy resource diversification. The high degree of influence of renewable energy sources on energy security in the EECCA countries has been proven in the implementation of the developed scenarios for its increase. Energy security is growing. At the same time, its level depends not only on an increase in the share of renewable sources but also on the structure of energy resources complex of countries, and the development of various renewable energy sources. Therefore, today the EECCA countries are forced not only to increase the share of renewable energy sources but also to attach strategic importance to the structural content of their energy complex.

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Resistance to Outflow of Cerebrospinal Fluid Determined by Bolus Injection Technique and Constant Rate Steady State Infusion in Humans

Neurosurgery ◽

10.1227/00006123-198503000-00010 ◽

1985 ◽

Vol 16 (3) ◽

pp. 336-340 ◽

Cited By ~ 28

Author(s):

Michael Kosteljanetz

Keyword(s):

Cerebrospinal Fluid ◽

Steady State ◽

Bolus Injection ◽

Point Of View ◽

Injection Technique ◽

Communicating Hydrocephalus ◽

Constant Rate ◽

High Degree ◽

Infusion Technique

Abstract Two methods for the determination of resistance to the outflow of cerebrospinal fluid, the bolus injection technique and the constant rate steady state infusion technique, were compared. Thirty-two patients with a variety of intracranial diseases (usually communicating hydrocephalus) were studied. There was a high degree of correlation between the resistance values obtained with the two methods, but values based on the bolus injection technique were systematically and statistically significantly lower than those obtained with the constant rate infusion test. From a practical point of view. both methods were found to be applicable in a clinical setting.

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