| 8004449 |
Takahashi Y, Shirasaki T, Yamanaka H, Ishibashi H, Akaike N: Physiological roles of glycine and gamma-aminobutyric acid in dissociated neurons of rat visual cortex. Brain Res. 1994 Mar 21;640(1-2):229-35.
The effects of glycine (Gly) and gamma-aminobutyric acid (GABA) on the neurons acutely dissociated from rat visual cortex (VC) were investigated in the whole-cell mode using a conventional patch-clamp technique. GABA and Gly evoked Cl- currents (ICl) in a concentration-dependent manner at a holding potential (VH) of -50 mV. The half maximum effective concentrations (EC50) were 4.64 x 10 (-6) M for GABA and 6.67 x 10 (-5) M for Gly. Strychnine and bicuculline reversively inhibited both 10 (-5) M GABA- and 10 (-4) M Gly-induced ICl in a concentration-dependent manner. The half maximum inhibitory concentrations (IC50) of strychnine on GABA- and Gly-induced currents were 4.00 x 10 (-6) M and 8.26 x 10 (-8) M, respectively. The IC50 values of bicuculline on GABA and Gly responses were 1.18 x 10 (-6) M and 2.97 x 10 (-4), respectively. GABA at 10 (-5) M, which is near the EC50 of the GABA response, induced ICl in all neurons tested (n = 83). However, Gly of 10 (-4) M, which is also near the EC50 of the Gly response, induced ICl in 34 out of 83 neurons tested (41%). Moreover, the maximum amplitude of the Gly response was about 60% of that of the GABA response. On the other hand, the enhancement of N-methyl-D-aspartate (NMDA, 3 x 10 (-4) M) response by Gly (10 (-6) M) was observed in all neurons (n = 36) whether they had the Gly-induced ICl or not.(ABSTRACT TRUNCATED AT 250 WORDS) |
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