Muscarinic antagonists microinjected into the subthalamic nucleus decrease muscular rigidity in reserpinized rats.
The ability of anticholinergic agents microinjected into the subthalamic nucleus to reduce reserpine-induced muscular rigidity was assessed in rats. The electromyographical activity of the gastrocnemius-soleus muscle was used as a parameter of muscular rigidity. Reserpine (5 mg/kg i.p.) produced the appearance of electromyographical activity. The muscarinic antagonists M3 (1.27 nmol of 4-DAMP) and M1 (2.36 nmol of pirenzepine) markedly reduced the reserpine-induced electromyographical activity, whereas the M2 antagonist AFDX-116 (2.37 nmol) had no effect. These results suggest that a high cholinergic tone in the subthalamic nucleus is associated with the reserpine-induced muscular rigidity. Moreover, the M3 muscarinic antagonist is more effective than the M1 muscarinic antagonist in reducing the muscular rigidity in reserpinized rats, a model of Parkinson's disease, by blocking the high cholinergic tone in the subthalamic nucleus.
Hernández-López
S
S
Departamento de Fisiología, Biofísica y Neurociencias, CINVESTAV-IPN, México D.F., Mexico.
Flores
G
G
Rosales
M G
MG
Sierra
A
A
Martínez-Fong
D
D
Aceves
J
J
D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D002697:Chloral Hydrate / Q000494:pharmacology; D018680:Cholinergic Antagonists / Q000494:pharmacology; D004576:Electromyography / Q000187:drug effects; D008124:Locomotion / Q000187:drug effects; D008297:Male; D008845:Microinjections; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D009127:Muscle Rigidity / Q000139:chemically induced / Q000188:drug therapy*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D010880:Piperidines / Q000494:pharmacology; D010890:Pirenzepine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012110:Reserpine / Q000009:adverse effects; D013565:Sympatholytics / Q000009:adverse effects; D013787:Thalamic Nuclei / Q000187:drug effects*
D018686:Anesthetics, Intravenous; D018680:Cholinergic Antagonists; D018727:Muscarinic Antagonists; D010880:Piperidines; D013565:Sympatholytics; D010890:Pirenzepine; D002697:Chloral Hydrate; C042375:4-diphenylacetoxy-1,1-dimethylpiperidinium; D012110:Reserpine