Equilibrium potential of GABA(A) current and implications for rebound burst firing in rat subthalamic neurons in vitro.
Reciprocally connected glutamatergic subthalamic and GABAergic globus pallidus neurons have recently been proposed to act as a generator of low-frequency oscillatory activity in Parkinson's disease. To determine whether GABA(A) receptor-mediated synaptic potentials could theoretically generate rebound burst firing in subthalamic neurons, a feature that is central to the proposed oscillatory mechanism, we determined the equilibrium potential of GABA(A) current (E(GABA(A))) and the degree of hyperpolarization required for rebound firing using perforated-patch recording. In the majority of neurons that fired rebounds, E(GABA(A)) was equal to or more hyperpolarized than the hyperpolarization required for rebound burst firing. These data suggest that synchronous activity of pallidal inputs could underlie rhythmic bursting activity of subthalamic neurons in Parkinson's disease.
Bevan
M D
MD
Medical Research Council Anatomical Neuropharmacology Unit, University Department of Pharmacology, Oxford OX1 3TH, United Kingdom.
Wilson
C J
CJ
Bolam
J P
JP
Magill
P J
PJ
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism; D017097:Electric Impedance; D005016:Ethoxzolamide / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010507:Periodicity; D010721:Phosphinic Acids / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000378:metabolism*; D012684:Sensory Thresholds / Q000502:physiology; D020530:Subthalamus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*; D013696:Temperature; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000494:pharmacology
D002257:Carbonic Anhydrase Inhibitors; D002712:Chlorides; D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D010721:Phosphinic Acids; D011412:Propanolamines; D011963:Receptors, GABA-A; C085075:CGP 55845A; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline; D005016:Ethoxzolamide