Lesion of the subthalamic nucleus reverses motor deficits but not death of nigrostriatal dopaminergic neurons in a rat 6-hydroxydopamine-lesion model of Parkinson's disease

Braz J Med Biol Res. 2010 Jan;43(1):85-95. doi: 10.1590/s0100-879x2009007500020. Epub 2009 Dec 4.

Abstract

The objective of the present study was to determine whether lesion of the subthalamic nucleus (STN) promoted by N-methyl-D-aspartate (NMDA) would rescue nigrostriatal dopaminergic neurons after unilateral 6-hydroxydopamine (6-OHDA) injection into the medial forebrain bundle (MFB). Initially, 16 mg 6-OHDA (6-OHDA group) or vehicle (artificial cerebrospinal fluid - aCSF; Sham group) was infused into the right MFB of adult male Wistar rats. Fifteen days after surgery, the 6-OHDA and SHAM groups were randomly subdivided and received ipsilateral injection of either 60 mM NMDA or aCSF in the right STN. Additionally, a control group was not submitted to stereotaxic surgery. Five groups of rats were studied: 6-OHDA/NMDA, 6-OHDA/Sham, Sham/NMDA, Sham/Sham, and Control. Fourteen days after injection of 6-OHDA, rats were submitted to the rotational test induced by apomorphine (0.1 mg/kg, ip) and to the open-field test. The same tests were performed again 14 days after NMDA-induced lesion of the STN. The STN lesion reduced the contralateral turns induced by apomorphine and blocked the progression of motor impairment in the open-field test in 6-OHDA-treated rats. However, lesion of the STN did not prevent the reduction of striatal concentrations of dopamine and metabolites or the number of nigrostriatal dopaminergic neurons after 6-OHDA lesion. Therefore, STN lesion is able to reverse motor deficits after severe 6-OHDA-induced lesion of the nigrostriatal pathway, but does not protect or rescue dopaminergic neurons in the substantia nigra pars compacta.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dopamine / physiology*
  • Immunohistochemistry
  • Male
  • Motor Activity / drug effects*
  • Motor Activity / physiology
  • N-Methylaspartate
  • Neurons / drug effects
  • Neurons / pathology*
  • Neurons / physiology
  • Parkinson Disease, Secondary / chemically induced
  • Parkinson Disease, Secondary / pathology*
  • Parkinson Disease, Secondary / physiopathology
  • Pharmaceutical Vehicles
  • Random Allocation
  • Rats
  • Rats, Wistar
  • Substantia Nigra / cytology*
  • Substantia Nigra / physiopathology
  • Subthalamic Nucleus / drug effects
  • Subthalamic Nucleus / injuries*
  • Subthalamic Nucleus / pathology
  • Subthalamic Nucleus / surgery
  • Tyrosine 3-Monooxygenase / metabolism

Substances

  • Pharmaceutical Vehicles
  • N-Methylaspartate
  • Tyrosine 3-Monooxygenase
  • Dopamine