Optokinetic and vestibulo-ocular reflex adjustment by GABA antagonists
| Autor: | Victor Nzobounsana, Marie-Helene Leroy, Annie Reber, Bernard Poitevin |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Cerebellum
Eye Movements Stimulation Pharmacology GABA Antagonists Behavioral Neuroscience chemistry.chemical_compound Vestibular nuclei Neural Pathways medicine Animals Picrotoxin gamma-Aminobutyric Acid Dose-Response Relationship Drug Rats Inbred Strains Optokinetic reflex Reflex Vestibulo-Ocular GABA receptor antagonist Vestibular Nuclei Rats medicine.anatomical_structure nervous system chemistry Reflex sense organs Vestibulo–ocular reflex Neuroscience |
| Zdroj: | Behavioural brain research. 81(1-2) |
| ISSN: | 0166-4328 |
| Popis: | We determined if high and low doses of anti-GABAergic drugs have opposite effects on the visuo-vestibular activity in pigmented rats and examined a possible correlation with the level of GABA in the related structures. First, the horizontal optokinetic and vestibulo-ocular reflexes of most animals were depressed by high doses of anti-GABAergic drugs (10 −3 M purified picrotoxin or 10 −6 M picrotoxin in unpurified vegetal extract). Simultaneously, a drop in GABA level in the cerebellum and posterior brainstem was detected. Second, after a subsequent injection (1 ml) of the diluted extract (10 −13 M picrotoxin), the reflexes returned to normal despite the fact that no correlation with the GABA level was found. These results demonstrate that small doses of anti-GABAergic drugs reverse the depressive effect created by large doses of these drugs on the oculomotor system, and even adjust the reflexes to the stimulation. This adjustment, without correlation with the GABA level, suggest a powerful effect of very low dose of the drug to modulate either the activity of the cerebellar inhibiting input or of the vestibular nuclei neurons or to trigger the adaptation by other neurotransmitter systems involved in the performances of the reflexes. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect