Subdural applications of NO scavenger or NO blocker to the cerebellum depress the adaptation of monkey post-saccadic smooth pursuit eye movements.
We examined pharmacologically whether cerebellar long-term depression (LTD) may play a role in the adaptation of smooth pursuit eye movements in two Macaca fuscata, which were trained to pursue a target moving in the horizontal plane in a 3 degrees step-10 deg/s ramp mode. The monkeys showed small catch-up saccades followed by 6-8 deg/s post-saccadic pursuit movements. Adaptation of the post-saccadic pursuit velocity was induced by repetition of acceleration of the target to 20 deg/s after the catch-up saccades. Injections of 0.1 mM hemoglobin or 20 mM NG-monomethyl-L-arginine solution into the subdural space above the paraflocculus-flocculus scarcely affected the post-saccadic pursuit velocity, but markedly depressed its adaptation. These observations suggest that cerebellar LTD may underlie the adaptation of smooth pursuit.
Nagao
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S
Department of Physiology, Jichi Medical School, Tochigi, Japan.
Kitazawa
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H
D000818:Animals; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006454:Hemoglobins / Q000494:pharmacology*; D007267:Injections; D008251:Macaca; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052248:Nitric Oxide Synthase Type I; D011698:Pursuit, Smooth / Q000187:drug effects*; D011859:Radiography; D013238:Stereotaxic Techniques; D013355:Subdural Space; D019323:omega-N-Methylarginine / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D006454:Hemoglobins; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I