Molecular Identification and Quantitative Analysis of Voltage‐gated K+ Channels of Rat Hypothalamic Paraventricular Nucleus Neurons

Abstract

The hypothalamic paraventricular nucleus (PVN), an important integrating site in regulating the neuroendocrine and autonomic nervous systems, is composed of heterogeneous neurons. These neurons are classified into two groups, type I and type II neurons, based on their electrophysiological properties. In the present study, we investigated the molecular identification of voltage‐gated K (Kv) channels. These are known to be associated with a delay in the onset of the first action potential, which is a distinctive characteristic of type I neurons.In order to identify the mRNA expression profiles, the PVN neurons were divided into type I and type II neurons according to their electrophysiological properties. The recorded cells were harvested and single‐cell RT‐PCR analysis was performed. The single‐cell RT‐PCR analysis revealed that Kv1.2, Kv1.3, Kv1.4, Kv4.1, Kv4.2, and Kv4.3 were expressed in both type I and type II neurons. The relative quantitative analysis revealed that the expression density of Kv1.2, Kv4.2, and Kv4.3 were significantly higher in type I neurons than in type II neurons. These results suggest that several Kv channels are present in both type I and type II neurons and Kv1.2, Kv4.2 and Kv4.3 are the potential Kv channels responsible for determining the distinct electrophysiological properties. This work is supported by National Research Foundation of Korea (2009‐0067186)