Developmental changes in the expression of Shaker- and Shab-related K+ channels in neurons of the rat trigeminal ganglion
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- 作者：Seifert ; Gerald ; Kuprijanova ; Elena ; Zhou ; Min ; et. al.
- 关键词：Patch-cl Single-cell RT-PCR ; Kv1 ; Kv2 ; Pharmacology
- 刊名：Molecular Brain Research
- 出版年：1999
- 出版时间：December 10, 1999
- 年：1999
- 卷：74
- 期：1-2
- 页码：55-68
- 全文大小：1.03 M
文摘
We have investigated properties of voltage-gated K+ channels in neurons of the pre- and postnatal rat trigeminal ganglion (TG). To correlate functional data with information on gene expression of Shaker- and Shab-related channels in these pseudo-unipolar neurons, the patch-clamp technique was combined with the single-cell reverse transcription-polymerase chain reaction (RT-PCR). A majority (80 % ) of prenatal TG neurons possessed only sustained delayed rectifier currents with half-maximal current inactivation at −30 mV. In the postnatal cells, steady-state inactivation of sustained currents occurred at more negative voltages (half-maximal inactivation at −58 mV). About 65 % of the postnatal cells displayed a transient outward component in addition to the sustained currents. With increasing age, the sensitivity of sustained currents to 4-aminopyridine (4-AP) decreased significantly. The Shaker channel toxins, α-dendrotoxin and agitoxin-2 (50 and 10 nM), were much less effective. Discrimination between both stages with tetraethylammonium chloride (5 mM) was not possible since the currents were reduced generally by about 50 % . After recording, the cell content was harvested and single-cell RT-PCR was performed to compare K+ current properties and mRNA expression within the same cell. Most cells simultaneously expressed several different Shaker- and Shab-like transcripts. At postnatal day 14, the frequency of cells carrying transcripts encoding Kv1.1 decreased. Detailed analysis revealed a higher 4-AP sensitivity of TG neurons expressing Kv1.1 transcripts.