GABAergic modulation in the substantia nigra of the striatal dopamine release and of the locomotor activity in rats exposed to helium pressure.
Helium-oxygen pressure induces in rodents an increase of both locomotor and motor activity (LMA) and of the striatal dopamine release, which could result from a decrease of GABA transmission in the substantia nigra. The effects of the GABA(A) receptor agonist muscimol and of the GABA(B) receptor agonist baclofen on the striatal dopamine release were measured using differential pulse voltammetry. Behavioural studies were performed in freely moving rats using actimetry. Whatever the drug used under helium pressure, bilateral administration in the substantia nigra pars reticulata (SNr) or in the substantia nigra pars compacta (SNc) counteracted the evoked dopamine release. However, only the baclofen reduced the LMA, while the muscimol administration in the SNr, but not in the SNc, increased it. These results indicate that different subtypes of GABA receptors would be involved in the control of the DA release and in the occurrence of LMA under helium pressure.
Balon
Norbert
N
Université de la Méditerranée et IMNSSA, EA 3280, Laboratoire de Physiopathologie et Action Thérapeutique des Gaz sous Pression, Faculté de Médecine Nord, IFR Jean Roche, 13916 cedex 20, Marseille, France.
Kriem
Badreddine
B
Weiss
Michel
M
Rostain
Jean-Claude
JC
D000399:Air Pressure; D000818:Animals; D001273:Atmosphere Exposure Chambers; D001418:Baclofen / Q000494:pharmacology; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000032:analysis / Q000378:metabolism*; D004333:Drug Administration Routes; D004563:Electrochemistry; D004567:Electrodes, Implanted; D018755:GABA Agonists / Q000494:pharmacology*; D058785:GABA-A Receptor Agonists; D058786:GABA-B Receptor Agonists; D006371:Helium / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009118:Muscimol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013378:Substantia Nigra / Q000187:drug effects* / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D014851:Wakefulness
D018755:GABA Agonists; D058785:GABA-A Receptor Agonists; D058786:GABA-B Receptor Agonists; D006371:Helium; D009118:Muscimol; D001418:Baclofen; D004298:Dopamine