[Reduction of apomorphine-induced rotation in rats with additional destruction of the pedunculopontine nucleus contralateral to the unilateral nigrostriatal lesion].
Pedunculopontine nucleus (PPN) has been proposed to be one of the responsible sites for dopamine agonist induced contraversive rotation in rats with unilateral dopaminergic denervation. However, previous experiments have not confirmed possible participation of PPN in this rotational behavior. To determine whether contralateral side of the PPN plays a vital role in this rotation, we investigated apomorphine induced rotation in rats with further destruction of unilateral PPN contralateral to the nigrostriatal lesion. First, rats with unilateral PPN lesioned with N-methyl-D aspartic acid (NMDA) showed contralateral rotation when they were injected with apomorphine 0.5 mg/kg s.c. Second, rats with right substantia nigra previously lesioned with 6-hydroxydopamine were microinjected with NMDA (PPN lesion group) or vehicle (sham lesion group) into the contralateral (left)side of the PPN. Contraversive rotation induced by apomorphine 0.05 mg/kg s.c. did not show any significant change in PPN lesion group as compared with sham lesion group. Whereas such rotation induced by apomorphine 0.5 mg/kg s.c. significantly reduced to 61% in PPN lesion group as compared with that in sham lesion group. These results could be interpreted as a partial cancellation of rotational activity to the contralateral side (left) by the potential rotational activity toward the opposite side (right) in rats with additional contralateral PPN lesion. Although PPN might not serve as an output route for the dopaminergic neurotransmission in the basal ganglia, PPN itself could rather induce some movement affecting the basal ganglia.
Kannari
K
K
Third Department of Medicine, Hirosaki University School of Medicine, Japan.
Maeda
T
T
Matsunaga
M
M
Suda
T
T
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001479:Basal Ganglia / Q000502:physiology; D003342:Corpus Striatum / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D018491:Dopamine Agonists / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D019578:Multiple System Atrophy; D016202:N-Methylaspartate; D011149:Pons / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012399:Rotation
D018491:Dopamine Agonists; D016202:N-Methylaspartate; D001058:Apomorphine