Elsevier

Neuroscience

Volume 103, Issue 4, 4 April 2001, Pages 899-919
Neuroscience

Distribution and expression of TREK-1, a two-pore-domain potassium channel, in the adult rat CNS

https://doi.org/10.1016/S0306-4522(01)00030-6Get rights and content

Abstract

TREK-1 is a member of the two-pore-domain potassium channel family which is expressed predominantly in the CNS. Using an anti-peptide polyclonal antiserum, we have determined the distribution of TREK-1 in the brain and spinal cord of adult rats. Specificity of the antiserum was tested using a TREK-1-transfected cell line and confirmed with c-myc-tagged TREK-1. In thin tissue sections, immunoreactivity was widespread throughout the rat brain and spinal cord. TREK-1-like signals were observed in the cerebral cortex, basal ganglia, hippocampus, and various other subcortical nuclei in the hypothalamus, thalamus, mesencephalon and rhombencephalon. TREK-1 labelling appeared to be over the entire cell membrane, including the cell body and processes. Cells that morphologically resembled projection neurones and interneurones but not glial cells were labelled. As interneurones and known GABAergic projection neurones were the predominant population labelled, we investigated the possibility that TREK-1 is expressed in GABA-containing neurones using a specific anti-GABA antiserum. Expression of TREK-1 in GABA-containing neurones was observed in a number of areas, including the isocortex, hippocampus and thalamus. Thus, TREK-1 expression defines a unique and specific subset of interneurones and principal cells.

These studies indicate a widespread distribution of TREK-1 potassium channels throughout the rat brain and spinal cord, with expression in a number of areas being demonstrated to be present on GABA-containing neurones.

Section snippets

Animals

Adult male Wistar rats (200–250 g, Charles River, UK) were kept in a fixed 12-h/12-h light–dark cycle with food and water provided ad libitum. All procedures performed on animals during this study conformed to the UK Animals (Scientific Procedures) Act, 1986, and all efforts were made to minimise animal suffering and reduce the number of animals used in this study.

Chemicals

All chemicals were purchased from Merck (UK) unless otherwise stated. The bovine serum albumin (BSA) used in all experiments was of a

Western blot analysis

Under non-reducing conditions, affinity-purified TREK-1 antiserum detected a high-molecular-weight aggregate (100–500 kDa) in c-myc-tagged TREK-1-transfected cells (Fig. 1A, lanes b and c). The immunoreactivity was specific to transfected cells and not detected in untransfected wild-type cells (Fig. 1A, lanes a, d and f). The aggregate was partially resolved into a 56-kDa monomer and a 112-kDa dimer after treatment with either β-mercaptoethanol (Fig. 1A, lane g) or 8 M urea (Fig. 1A, lanes h and

Discussion

In these studies, we have used an antibody raised against a 17-amino-acid-containing peptide sequence that is present at the intracellular N-terminal of the human,29 rat (Chapman C. G., personal communication) and mouse TREK-1.8 Searching with this sequence in the GenEMBL database indicates that this 17-amino-acid sequence is unique to TREK-1. Western blots using cell lysates from human TREK-1-transfected cells were carried out in order to establish the specificity of the antibody. The blots

Conclusion

We have reported the distribution of TREK-1 potassium channel protein visualised with a polyclonal anti-peptide antibody. The distribution of TREK-1 potassium channels indicates that they are often expressed in GABAergic cells. The functional involvement of TREK-1 potassium channels in a number of neuronal systems, however, requires further investigations which will become more accessible once specific pharmacological modulators of these channels have been identified.

Acknowledgements

We would like to thank C. G. Chapman for information on the rat TREK-1 sequence.

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