Are retinal or mesencephalic dopaminergic systems involved in monocular optokinetic nystagmus asymmetry in frog?
In monocular vision, frogs display a unidirectional optokinetic horizontal nystagmus (H-OKN) reacting only to temporal-nasal (T-N) stimulation. The N-T component is almost absent. The analysis of search coil recordings after administration of dopamine into the viewing eye, the occluded eye or directly into the pretectum, hardly modifies the H-OKN triggered by the viewing eye irrespective of the concentration used. Conversely, administration of Piribedil, a strong D2 dopamine agonist, provokes the appearance of a N-T component, suppressing the monocular H-OKN asymmetry, whether the drug is injected by intravitreal or intrapretectal route. It is suggested that Piribedil could also bind with receptors other than dopamine's.
Jardon
B
B
Laboratoire de Neurophysiologie et Biologie des Comportements, Centre de Neurochimie, CNRS UPR 419, Strasbourg, France.
Bonaventure
N
N
D000818:Animals; D004298:Dopamine / Q000494:pharmacology; D008636:Mesencephalon / Q000502:physiology*; D017120:Nystagmus, Optokinetic / Q000187:drug effects / Q000502:physiology*; D010891:Piribedil / Q000494:pharmacology; D011893:Rana esculenta; D017448:Receptors, Dopamine D2 / Q000187:drug effects; D011976:Receptors, Muscarinic / Q000502:physiology; D012160:Retina / Q000502:physiology*; D013997:Time Factors; D015349:Vision, Monocular / Q000502:physiology*
D017448:Receptors, Dopamine D2; D011976:Receptors, Muscarinic; D010891:Piribedil; D004298:Dopamine