ISSN:
1432-2013
Keywords:
Serotonin
;
Inward rectifying potassium channel
;
Brain
;
PKC
;
5-HT2C receptor
;
Heterologous expression
;
Xenopus laevis oocytes
;
Modulation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract InXenopus laevis oocytes injected with rat brain poly(A)+ RNA, perfusion with a high-K+ solution (96 mM KCl) generated an inward current (I HK) which was absent in water-injected oocytes. Part ofI HK was blocked by low concentrations of Ba2+ (half-maximal inhibitory concentration, IC50: 4.2 ± 0.5 μM). When serotonin (5-HT) was applied to these oocytes a transient inward oscillating Cl− current arising from activation of Ca2+ -dependent Cl− channels,I Cl(Ca), was observed. When this response decayed, a 30% reduction ofI HK could be detected. Electrophysiological characterization of the K+ channel down-modulated by 5-HT revealed that it is an inward rectifier. Antisense suppression experiments revealed that the 5-HT2C receptor mediates the down-modulatory effect of 5-HT. The nature of the modulatory pathway was investigated by application of phorbol esters and intracellular injection of protein kinase C (PKC) inhibitors, ethylenebis (oxonitrilo)tetraacetate (EGTA) and inositol 1, 4, 5-trisphosphate. The results demonstrate that PKC is responsible for the down-modulatory effect.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02207270
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