Qualitative identity of cerebral neuronal membrane actions of 5HT LSD, and CPZ.

Extra- and intracellular recording of the cerebral cortical actions of close-arterially injected serotonin (5HT) and LSD in the cat shows them to be powerful synaptic inhibitors. They are specifically and differentially blocked by chlorpromazine (CPZ). The membrane parameters including spike generation, polarization, transmembrane conductance, and IPSPs show that all three produce qualitatively identical changes, which must, therefore, be presumed to act on the same receptors with block by CPZ taking place because of competitive inhibition.

Hallucinogen-tranquilizer interaction: its nature.

Study of the competition between hallucinogens and tranquilizers at cerebral synapses and on behavior in various species of animals indicates a continuum of effects from protection to dominance of tranquilizer toxicity as the dose of tranquilizer increases. Data on cat and monkey behavior, supplementing that on the rat, show that it is possible to arrive at a tranquilizer dose that can aggravate instead of protect, in accord with the competitive inhibitory nature of the interaction of hallucinogen and tranquilizer.

Cerebral synaptic transmission and behavioral effects of dimethoxyphenylethylamine: a potential psychotogen.

Dimethoxyphenylethylamine, like mescaline which it resembles, impairs cerebral synaptic transmission and behavior in cats. It has properties associated with hallucinogens and, on this score, qualifies as a potential inducer of psychosis. The idea of such an endogenous inducer is thus reaffirmed by the candidacy of dimethoxyphenylethylamine.

Cerebrally active small moiety from "taraxein-like" blood fractions.

A charged, amphoteric, smiall moiety has been separated from a "taraxein-like" blood fraction by electrodialysis throuighl ion exchange membranes. Cerebral bioassay shows that the activity of the blood extract is contained in the charged small moiety so that, as the activity in the charged compartment rises during electrodialysis, the activity in the feeding (extract) compartment falls.

Carotid and vagal afferents and drug action on transcallosally evoked cortical potentials.

The use of transcallosally evoked cortical potentials to study the action of intracarotidly injected drugs on cerebral synapses has necessitated the demonstration that vagal, baroreceptor, and chemoreceptor influences do not play essential roles in the drug effects observed-for example, the cerebral synaptic inhibitory action of serotonin.

A quantifiable behavioral correlate of psychotogen and tranquilizer actions.

A representative psychotogen, lysergic acid diethylamide (LSD-25), in doses small enough to be devoid of gross effects, increases response latency in rats to a tone indicating the availability of water reward; this effect is greatly reduced by prophylactic administration of a representative phenothiazine tranquilizer, chlorpromazine (CPZ), in doses that per se do not affect performance. The nature of the chlorpromazine action and its competition with lysergic acid diethylamide is revealed by the effects of chlorpromazine in larger doses.