Abstract
Lysergic acid diethylamide (LSD), a compound derived from ergot alkaloids, produces in human subjects a characteristic mental disturbance with visual hallucinations and other psychotic symptoms in a very small dose. Studies of the effects of LSD on spontaneous cortical activity in animals have been reported by a number of investigators. Bradley and Elkes (1) reported that LSD produced rhythms not unlike those seen in the normal alert animal, i.e., low amplitude, diffuse fast (15 to 30 c/sec) activity in all regions of the brain of the conscious cats. Rinaldi and Himwich (2) studied the effects of LSD on the spontaneous cerebral activity in curarized rabbits and found that it caused a continuous “alert pattern” in small doses (10 to 15 μg/kg).
Recently, Yui and Takeo (3) reported on central actions of a new series of ergot alkaloids isolated by Abe et al.. The excitor group among these alkaloids produced in various species of animals characteristic symptoms with hyperpnoea, mydriasis, increase in the spontaneous activity and anxiety which were similar to those induced by LSD, and antagonized markedly reserpine-sedation. Moreover, some of these alkaloids antagonized some action of serotonin in vitro as well as in vivo. On the other hand, in contrast to the above-mentioned alkaloids, some of their dihydro-derivatives (the inhibitor group) produced in animals a syndrome probably attributed to depression of central nervous system.
From these results, it may be expected that these alkaloids produce certain electrophysiological changes of cerebral activity.
The experiments were performed on agroclavine and elymoclavine as representatives of the excitor group and dihydroagroclavine and dihydroelymoclavine of the inhibitor group.
This report is concerned with ; 1) the effects of these four alkaloids on the spontaneous cortical activity of curarized or non-curarized rabbit in comparison with LSD, methylamphetamine and physostigmine, 2) how these EEG-effects are modified by some central depressants.
