Daily rhythms of benzodiazepine receptor numbers in frontal lobe and cerebellum of the rat.
Behavioural, biochemical and neurophysiological evidence suggests that gamma-aminobutyric acid (GABA) may play an important role in the neural control of circadian rhythms. Central receptors for benzodiazepines are functionally coupled to GABA receptors and appear to mediate behavioural effects of exogenous benzodiazepines. The binding of 3H-flunitrazepam to synaptic plasma membranes prepared from various regions of rat brain was examined at 6-hour intervals over a 36-hour period. Prominent daily rhythms in receptor number (Bmax) were observed in the frontal lobe and the cerebellum but not in the temporoparietal regions, hypothalamus or medulla/pons. Binding was highest during periods of sleep/low activity with a significant decrease occurring just prior to waking. These results suggest that daily fluctuations in benzodiazepine receptor numbers may be related to the temporal control of sleep/wake and muscle activity cycles.
Brennan
M J
MJ
Volicer
L
L
Moore-Ede
M C
MC
Borsook
D
D
D000818:Animals; D002531:Cerebellum / Q000378:metabolism*; D002940:Circadian Rhythm; D005445:Flunitrazepam / Q000378:metabolism; D005625:Frontal Lobe / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism; D010296:Parietal Lobe / Q000378:metabolism; D011149:Pons / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000378:metabolism*; D012890:Sleep / Q000502:physiology; D013570:Synaptic Membranes / Q000378:metabolism; D013702:Temporal Lobe / Q000378:metabolism; D014851:Wakefulness / Q000502:physiology
D011963:Receptors, GABA-A; D005445:Flunitrazepam