Lesions of the entopeduncular nucleus and the subthalamic nucleus reduce dopamine receptor antagonist-induced catalepsy in the rat.
The role of the entopeduncular nucleus (EP) and the subthalamic nucleus (STN) in mediating dopamine receptor antagonist-induced catalepsy in the rat was investigated. Five days after bilateral lesions of EP and STN respectively with the excitotoxin quinolinic acid (15, 30 nmol/0.5 microliter/side and 24 nmol/0.5 microliter/side, respectively) rats were injected intraperitoneally with the dopamine D1 receptor antagonist SCH 23390 (0.5 mg/kg) or the dopamine D2 receptor antagonist haloperidol (0.5 mg/kg). Complete EP lesions prevented both SCH 23390- and haloperidol-induced catalepsy. STN lesions exerted pronounced anticataleptic effects in case of haloperidol-induced catalepsy, but less pronounced in case of SCH 233390-induced catalepsy. Further characterization of these anticataleptic effects in an open field demonstrated, that neither EP- nor STN lesions reversed bradykinesia, which occurred after selective dopamine receptor blockade. In conclusion, both EP and STN participate in the mediation of catalepsy induced by dopamine D1- and dopamine D2 receptor antagonists. Thereby these nuclei preferentially mediate rigidity and akinesia, but to a lesser extent bradykinesia.
Zadow
B
B
Zoological Institute, University of Tübingen, Germany.
Schmidt
W J
WJ
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D001931:Brain Mapping; D003342:Corpus Striatum; D018492:Dopamine Antagonists / Q000494:pharmacology*; D005917:Globus Pallidus / Q000187:drug effects* / Q000502:physiology; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009048:Motor Skills / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000502:physiology; D013378:Substantia Nigra / Q000187:drug effects* / Q000502:physiology; D013787:Thalamic Nuclei / Q000187:drug effects* / Q000502:physiology
D001552:Benzazepines; D018492:Dopamine Antagonists; D011954:Receptors, Dopamine; D006220:Haloperidol