GABAERGIC INHIBITORY INPUTS TO SUBFORNICAL ORGAN NEURONS IN RAT SLICEPREPARATIONS

INENAGA K NAGATOMO T HONDA E UETA Y YAMASHITA H

K. Inenaga et al., GABAERGIC INHIBITORY INPUTS TO SUBFORNICAL ORGAN NEURONS IN RAT SLICEPREPARATIONS, Brain research, 705(1-2), 1995, pp. 85-90

24

INGLESE

Article

Neurosciences

Brain research → ACNP

0006-8993

705

1-2

1995

85 - 90

ISI

0006-8993(1995)705:1-2<85:GIITSO>2.0.ZU;2-O

To investigate GABAergic inhibitory inputs to neurons of the subfornic al organ (SFO), intracellular recordings were made in rat brain slice preparations. Inhibitory postsynaptic potentials, which occurred spont aneously or were evoked by focal electric stimulation, had reversal po tentials of approximately - 60 mV, and were almost totally abolished b y the GABA(A) antagonists bicuculline at 3-100 mu M or picrotoxin at 5 0 mu M. Following the application of bicuculline or picrotoxin, the re sting membrane potentials were decreased by 4-8 mV. GABA at 10-100 mu M and the GABA(A) agonist muscimol at 1-100 mu M decreased the membran e resistance and the firing rate in all neurons tested. The reversal p otential of the response to muscimol was similar to that for inhibitor y postsynaptic potentials. The actions of muscimol persisted in the pr esence of 1 mu M tetrodotoxin, implying that muscimol must act directl y on the recorded neurons. These results suggest that there is a tonic inhibitory GABAergic input to SFO neurons which are mainly mediated t hrough GABA(A) receptors.