Electrical Excitability in the Rat Clonal Pituitary Cell and Its Relation to Hormone Secretion
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- OZAWA Seiji
- Department of Physiology, Jichi Medical School
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- MIYAZAKI Shun-ichi
- Department of Physiology, Jichi Medical School
Bibliographic Information
- Other Title
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- Electrical Excitability in the Rat Clon
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Abstract
Membrane electrical properties of the clonal anterior pituitary cell (GH3) were studied using intracellular recording techniques. The resting potential in the GH3cell was -48.0±1.1 mV (mean±S.E., n=39) in normal saline. The input resistance estimated from the linear portion of the current-voltage relationship was 453±30 MΩ(n=21). The maximum rate of rise of the action potential was 7.0±1.1 V/sec (n=12) at room temperature (23-25°C). The action potential had both Na and Ca components. The Ca component was abolished by addition of 4 mm Co2+. Sr2+ could substitute for Ca2+in supporting spike initiation. As the concentration of Sa2+ was increased, the maximum rate of rise of the action potential increased. After replacement of Ca2+with isomolar Ba2+ the membrane potential shifted to -6.1±1.1 mV (n=11). In the Ba solution, prolonged action potentials were evoked by a depolarizing current pulse after maintaining the membrane potential more negative than -50 mV. The release of both prolactin and growth hormone was enhanced by increasing the external K+ concentration to 50 mm in the presence of Ca2+. Sr2+could substitute for Ca2+. Ba2+enhanced the release of both hormones, even if the K+ concentration was unaltered. The facilitatory effects of high K+ and Ba2+were markedly suppressed by addition of 2-4 mm Co2+. These results may suggest that the potential-dependent increase in the membrane permeability to Ca2+, responsible for initiation of the Ca spike, plays a significant role in stimulation of hormone secretion in GH3 cells.
Journal
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- The Japanese Journal of Physiology
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The Japanese Journal of Physiology 29 (4), 411-426, 1979
THE PHYSIOLOGICAL SOCIETY OF JAPAN
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Details 詳細情報について
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- CRID
- 1390001205040910080
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- NII Article ID
- 130003476735
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- NII Book ID
- AA00691224
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- COI
- 1:CAS:528:DyaE1MXmtVynsrs%3D
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- ISSN
- 18811396
- 0021521X
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- NDL BIB ID
- 2077532
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- PubMed
- 533944
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- Text Lang
- en
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- Data Source
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- JaLC
- NDL
- Crossref
- PubMed
- CiNii Articles
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- Abstract License Flag
- Disallowed