Please wait, while we are loading the content...
Please wait, while we are loading the content...
| Content Provider | PubMed Central |
|---|---|
| Author | Winegar, B. D. Lansman, J. B. |
| Abstract | 1. The blocking actions of Zn2+ on currents carried by Ba2+ through single dihydropyridine-sensitive Ca2+ channels were recorded from cell-attached patches on myotubes from the mouse C2 cell line. 2. Adding 100 microM-Zn2+ to the patch electrode containing 110 mM-BaCl2 produced an increase in the open channel noise, presumably arising from unresolved blocking and unblocking of the open channel by Zn2+. Adding between 200 and 1000 microM-Zn2+ to the electrode reduced the amplitude of the unitary current in a concentration-dependent manner. 3. The single-channel current-voltage (i-V) relations showed that Zn2+ reduced the amplitude of the unitary Ba2+ currents at all potentials more negative than 0 mV. A plot of the amplitude of the unitary current in the presence of Zn2+, normalized to the amplitude in its absence, showed that block of the current depended on voltage, decreasing as the patch potential was made more negative. 4. The normalized amplitudes of the unitary currents were plotted as a function of the logarithm of [Zn2+] in the electrode. The relation for currents recorded at different potentials were fitted to an expression for binding to a single site with a KD at 0 mV of approximately 500 microM. The KD changed approximately e-fold per 83 mV with hyperpolarization. The results suggest Zn2+ binds to a site located at approximately 15% of the potential drop from the surface membrane. 5. Reducing the concentration of Ba2+ in the patch electrode enhanced the steady-state block of unitary currents by Zn2+. The inverse of the unitary current was plotted as a function of [Ba2+]o in the presence and absence of Zn2+; both were linear and intersected at the ordinate, indicating Ba2+ and Zn2+ compete for a channel site. 6. The kinetics of Zn2+ block of unitary Ba2+ currents were studied by amplitude distribution analysis. As expected for a simple reaction between blocking ion and open channel, the blocking rate depended linearly on the concentration of Zn2+, while the exit rate was independent of concentration. The second-order rate coefficient for Zn2+ entry in the presence of 110 mM-BaCl2 at 0 mV was approximately 2.0 X 10(7) M-1S-1, while the exit rate was approximately 16000 s-1. 7. Both entry and exit rates increased as the membrane potential was made more negative. The entry rate increased approximately e-fold per 66 mV, while the exit rate increased approximately e-fold per 41 mV.(ABSTRACT TRUNCATED AT 400 WORDS) |
| Ending Page | 578 |
| Starting Page | 563 |
| File Format | |
| ISSN | 14697793 |
| e-ISSN | 14697793 |
| Journal | The Journal of Physiology |
| Volume Number | 425 |
| Language | English |
| Publisher Date | 1990-06-01 |
| Access Restriction | Open |
| Subject Keyword | Research in Higher Education |
| Content Type | Text |
| Resource Type | Article |
| Subject | Physiology Sports Science |
National Digital Library of India (NDLI) is a virtual repository of learning resources which is not just a repository with search/browse facilities but provides a host of services for the learner community. It is sponsored and mentored by Ministry of Education, Government of India, through its National Mission on Education through Information and Communication Technology (NMEICT). Filtered and federated searching is employed to facilitate focused searching so that learners can find the right resource with least effort and in minimum time. NDLI provides user group-specific services such as Examination Preparatory for School and College students and job aspirants. Services for Researchers and general learners are also provided. NDLI is designed to hold content of any language and provides interface support for 10 most widely used Indian languages. It is built to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is designed to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is developed, operated and maintained from Indian Institute of Technology Kharagpur.
Learn more about this project from here.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Education, through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
| Sl. | Authority | Responsibilities | Communication Details |
|---|---|---|---|
| 1 | Ministry of Education (GoI), Department of Higher Education |
Sanctioning Authority | https://www.education.gov.in/ict-initiatives |
| 2 | Indian Institute of Technology Kharagpur | Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project | https://www.iitkgp.ac.in |
| 3 | National Digital Library of India Office, Indian Institute of Technology Kharagpur | The administrative and infrastructural headquarters of the project | Dr. B. Sutradhar bsutra@ndl.gov.in |
| 4 | Project PI / Joint PI | Principal Investigator and Joint Principal Investigators of the project |
Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon |
| 5 | Website/Portal (Helpdesk) | Queries regarding NDLI and its services | support@ndl.gov.in |
| 6 | Contents and Copyright Issues | Queries related to content curation and copyright issues | content@ndl.gov.in |
| 7 | National Digital Library of India Club (NDLI Club) | Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach | clubsupport@ndl.gov.in |
| 8 | Digital Preservation Centre (DPC) | Assistance with digitizing and archiving copyright-free printed books | dpc@ndl.gov.in |
| 9 | IDR Setup or Support | Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops | idr@ndl.gov.in |
|
Loading...
|