Abstract
The biphasic mode of action of gamma-butyrolactone (GBL) and gamma-hydroxybutyrate (GHB) in the central nervous system has been confirmed in the previous report (1). The former compound elevates the reticular arousal stimulation threshold for the manifestation of the hippocampal theta waves without significantly affecting the increased manifestation of the fast waves in the rabbit's EEG. At the same time, the thalamic recruiting response is usually depressed or sometimes is slightly augmented. In order to observe the mode of action on the brain structures more in detail, the effects of both compounds on the cortical dendritic responses (DR) caused by the electrical stimulation of the cortical surface are studied in the cats.
The small doses of GHB augment the DR, while the large doses inhibit it. Based on the obtained results the dose-response relationship of GHB and its related compounds is discussed. On the other hand, GBL proved to be inactive in this respect. Correlation of the effects between GHB and gamma-aminobutyric acid (GABA), the latter of which is now accepted as the inhibitory transmitter in the several parts of the central nervous system, is also investigated. Roth et al. (2, 3) have already postulated that GHB is the pharmacologically active metabolite derived from gamma-butyrolactone in the body.
