TY - JOUR
T1 - Effects of GABA and anxiolytics on the single unit discharge of suprachiasmatic neurons in rat hypothalamic slices
AU - Liou, S. Y.
AU - Shibata, S.
AU - Albers, H. E.
AU - Ueki, S.
N1 - Funding Information:
This work was supported by NOOO14-89-J-1640f rom the Office of Naval Researcht o H.E.A. The authorst hank the CIBACEIGY Corporation for providing the baclofen used in this study.
PY - 1990/7
Y1 - 1990/7
N2 - The effects of gamma-aminobutyric acid (GABA), muscimol, baclofen and the anxiolytics; diazepam (DZP), flurazepam (FZP) and zopiclone on single-unit neural activities in the suprachiasmatic nucleus (SCN) were investigated using the rat hypothalamic slice preparation. Exposure of the slice to GABA 10-4 M produced inhibitory responses in 65% of the 49 SCN neurons examined. The threshold concentration of GABA ranged from 10-6 to 10-f4 M. Neurons responsive to GABA were not found to be restricted to a subdivision of the SCN, but were diffusely distributed throughout the nucleus. DZP, FZP and zopiclone produced responses similar to those of GABA. The inhibitory effects of GABA (10-5 M) were potentiated by coadministration of DZP (10-5 M). Muscimol and baclofen (10-7 M to 10-4 M) also inhibited SCN neuronal activity in a dose-dependent manner. Bicuculline (10-5 M-10-4 M) scarcely affected the baclofen-induced inhibition ( 1 6) but strongly antagonized the effects of muscimol ( 6 6), GABA ( 6 8) and DZP ( 4 5). These results suggest that the receptors mediating the inhibitory effects of GABA and anxiolytics within the SCN may be GABAA and/or GABAB or GABA-BDZ receptor complex, respectively.
AB - The effects of gamma-aminobutyric acid (GABA), muscimol, baclofen and the anxiolytics; diazepam (DZP), flurazepam (FZP) and zopiclone on single-unit neural activities in the suprachiasmatic nucleus (SCN) were investigated using the rat hypothalamic slice preparation. Exposure of the slice to GABA 10-4 M produced inhibitory responses in 65% of the 49 SCN neurons examined. The threshold concentration of GABA ranged from 10-6 to 10-f4 M. Neurons responsive to GABA were not found to be restricted to a subdivision of the SCN, but were diffusely distributed throughout the nucleus. DZP, FZP and zopiclone produced responses similar to those of GABA. The inhibitory effects of GABA (10-5 M) were potentiated by coadministration of DZP (10-5 M). Muscimol and baclofen (10-7 M to 10-4 M) also inhibited SCN neuronal activity in a dose-dependent manner. Bicuculline (10-5 M-10-4 M) scarcely affected the baclofen-induced inhibition ( 1 6) but strongly antagonized the effects of muscimol ( 6 6), GABA ( 6 8) and DZP ( 4 5). These results suggest that the receptors mediating the inhibitory effects of GABA and anxiolytics within the SCN may be GABAA and/or GABAB or GABA-BDZ receptor complex, respectively.
KW - Anxiolytics
KW - Brain slice
KW - Gamma-aminobutyric acid
KW - Single unit activity
KW - Suprachiasmatic nucleus
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U2 - 10.1016/0361-9230(90)90259-3
DO - 10.1016/0361-9230(90)90259-3
M3 - Article
C2 - 1976421
AN - SCOPUS:0025118410
SN - 0361-9230
VL - 25
SP - 103
EP - 107
JO - Journal of Electrophysiological Techniques
JF - Journal of Electrophysiological Techniques
IS - 1
ER -