Basic electrophysiological properties of rat adrenal chromaffin cells and their sensitivity to muscarine were studied under voltage-clamp. Whole-cell patch-clamp recording of primary cultures of rat chromaffin cells reveals a prominent sodium current and one sustained component of calcium current. Outward currents are carried by three kinds of potassium currents: (1) a voltage-activated delayed-rectifier, (2) a voltage-dependent calcium-activated current and (3) a voltage-insensitive calcium-activated current. Muscarine (0.5 to 50 micromolar) suppresses spontaneous action potential firing and induces a slow outward current. This response persists in the presence of cobalt (5 millimolar). Voltage ramps during the response reveal that muscarine activates both voltage-dependent, TEA-sensitive and voltage-independent, curare-sensitive potassium currents in a manner consistent with a transient elevation of intracellular calcium. However, in some cells a marked transient suppression of the voltage-dependent component occurs coincident with the muscarine-induced increase in the voltage-independent potassium component. The suppression of the voltage-dependent component is washout sensitive in that it disappears over time, while the activation response is well maintained. / Source: Dissertation Abstracts International, Volume: 51-05, Section: B, page: 2230. / Major Professor: Christopher John Lingle. / Thesis (Ph.D.)--The Florida State University, 1990.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78259 |
| Contributors | Neely, Alan., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 254 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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