# Paecilomycies japonica reduces repeated nicotine-induced neuronal and behavioral activation in rats

## TL;DR

This study shows that Paecilomyces japonica reduces nicotine's effects on brain activity and behavior in rats, suggesting it could help treat nicotine addiction.

## Contribution

The study is the first to demonstrate Paecilomyces japonica's effects on nicotine-induced brain and behavioral changes in rats.

## Key findings

- Paecilomyces japonica reduced nicotine-induced locomotor sensitization in rats.
- It decreased c-Fos and TH expression in key brain regions like the nucleus accumbens and ventral tegmental area.
- The effects suggest modulation of dopaminergic systems involved in nicotine addiction.

## Abstract

Many studies have demonstrated that repeated injections of nicotine can produce progressive increases in locomotor activity and enhanced expression of c-fos and tyrosine hydroxylase (TH) in brain dopaminergic areas. Paecilomyces japonica (PJ) is a herbal medicine that is commonly used to treat opiate and other addictions in Eastern Asia. However, its influence on nicotine addiction has not been examined. This study was carried out to investigate the effects of PJ on repeated nicotine-induced behavioral sensitization of locomotor activity and c-Fos and TH expression in the rat brain using immunohistochemistry.

Rats were pretreated with PJ (10, 25, 50, 100, and 200 mg/kg, intraperitoneally) 30 min before repeated injections of nicotine (0.4 mg/kg, subcutaneously, twice daily for 7 days). Locomotor activity was measured in rats during 7-day nicotine treatments. On the seventh day, c-Fos and TH expression were assessed.

Pretreatment with PJ decreased the development of nicotine-induced sensitization, c-Fos expression in the nucleus accumbens and striatum, and TH expression in the ventral tegmental area. PJ decreased nicotine-induced locomotor activity by modulating brain dopaminergic systems.

The results of the present study suggest that PJ may be a useful agent for preventing and treating nicotine addiction.