Inhibitory effect of GABA (gamma-aminobutyric acid) on the induction of long-term potentiation in guinea pig superior colliculus slices.
Superior colliculus (SC) slices were prepared from guinea pigs and postsynaptic potentials (PSPs) were recorded in the superficial grey layer of the SC after electrical stimulation to the optic layer (OL). Tetanic stimulation of 50 Hz frequency and 20 s duration to the OL induced long-term potentiation (LTP) in the PSP increasing the amplitude to 140% of the original level in 30 min. Tetanic stimulation failed to induce LTP after application of gamma-aminobutyric acid (GABA) (300 microM, 1 or 3 mM) to the perfusion medium. On the other hand, tetanic stimulation to the OL after application of bicuculline methiodide (1 microM), a GABAA receptor antagonist, facilitated the formation of LTP. These results indicate that GABA modulates the formation of LTP in the SC.
Hirai
H
H
Department of Physiology, School of Medicine, Kobe University, Japan.
Tomita
H
H
Okada
Y
Y
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004558:Electric Stimulation; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009473:Neuronal Plasticity / Q000187:drug effects*; D013477:Superior Colliculi / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D005680:gamma-Aminobutyric Acid; D001640:Bicuculline