No abstract

A test procedure, inducing a defined state of vigilance in rats, has been investigated to ascertain its usefulness for EEG monitoring of the effects of drugs. In order to prevent spontaneous fluctuations in the level of vigilance, rats were trained to walk in a slowly rotating treadwheel. The level of vigilance recorded under these conditions could be shifted by amphetamine, 1.0 mg/kg p.o., to a higher state of arousal, as shown by a reduction in power in all frequency bands, and by diazepam, 0.3 mg/kg p.o., to a lower state of arousal, as indicated by a rise in the activity at low frequencies. Imipramine (1.0, 3.0 and 10.0 mg/kg p.o.) caused a dose-related reduction in power in the intermediate frequency bands (3–18 Hz).

No abstract

High-affinity uptake of [3H]gamma-aminobutyric acid (GABA) was studied in cultures of neonatal rat cortical neurons grown on pre-formed monolayers of non-neuronal (glial) cells. Both the maximum rate (Vmax) and, to a smaller extent, the Km of [3H]GABA uptake increased with time. In addition, in parallel with these changes, 2,4-diaminobutyric acid and cis-3-aminocyclohexane-1-carboxylic acid (ACHC), compounds which are considered typical substrate/inhibitors of GABA uptake in neurons, became progressively stronger inhibitors of [3H]GABA uptake. Consequently, the present results may mean that the studies using uptake of [3H]GABA, [3H]ACHC, or [3H]DABA as a specific marker for GABAergic neurons differentiating during the ontogenetic development of the central nervous system may have to be interpreted with caution.