# Chronic pain enhances excitability of corticotropin-releasing factor-expressing neurons in the oval part of the bed nucleus of the stria terminalis

## TL;DR

Chronic pain increases the excitability of CRF-expressing neurons in a brain region called the BNST, which may contribute to aversive and reward-related behaviors.

## Contribution

This study is the first to show that chronic pain directly enhances the excitability of CRF neurons in the ovBNST.

## Key findings

- Chronic pain reduces rheobase and firing threshold of ovBNSTCRF neurons.
- Chronic pain increases the firing rate of ovBNSTCRF neurons compared to controls.
- CRF neurons in the ovBNST show heightened excitability in a neuropathic pain model.

## Abstract

We previously reported that enhanced corticotropin-releasing factor (CRF) signaling in the bed nucleus of the stria terminalis (BNST) caused the aversive responses during acute pain and suppressed the brain reward system during chronic pain. However, it remains to be examined whether chronic pain alters the excitability of CRF neurons in the BNST. In this study we investigated the chronic pain-induced changes in excitability of CRF-expressing neurons in the oval part of the BNST (ovBNSTCRF neurons) by whole-cell patch-clamp electrophysiology. CRF-Cre; Ai14 mice were used to visualize CRF neurons by tdTomato. Electrophysiological recordings from brain slices prepared from a mouse model of neuropathic pain revealed that rheobase and firing threshold were significantly decreased in the chronic pain group compared with the sham-operated control group. Firing rate of the chronic pain group was higher than that of the control group. These data indicate that chronic pain elevated neuronal excitability of ovBNSTCRF neurons.

The online version contains supplementary material available at 10.1186/s13041-024-01094-6.