1 Department of Physiology and Pathophysiology, School of Medicine, Xi’an Jiaotong University, Xi’an 710061, China 
2 Department of Neurology, the Second Hospital, Xi’an Jiaotong University, Xi’an 710004, China 
3 Key Laboratory of Environment- and Genes- Related Diseases, Ministry of Education of China, Xi’an 710061, China

Abstract 

Objective 
To investigate the changes in the firing activity of noradrenergic neurons in the locus coeruleus (LC) in a rat model of Parkinson disease (PD). 
Methods 
2 and 4 weeks after unilateral lesion of the nigrostriatal pathway in the rat by local injection of 6-hydroxydopamine (6-OHDA) into the right substantia nigra pars compacta (SNc), the firing activity of noradrenergic neurons in LC was recorded by extracellular single unit recording. 
Results 
The firing rate of LC noradrenergic neurons increased significantly 2 and 4 weeks after 6-OHDA lesions compared to normal rats, respectively (P < 0.05). The percentage of irregularly firing neurons was obviously higher than that of normal rats during the fourth week after SNc lesion (P < 0.05). 
Conclusion 
LC noradrenergic neurons are overactive and more irregular in 6-OHDA-lesioned rats. These changes suggest an implication of the LC in the pathophysiological mechanism of PD.

Keywords

locus coeruleus; 6-hydroxydopamine; Parkinson disease; electrophysiology

[SpringerLink]