Interaction of psychotropic agents with central neurotransmitters as revealed by their effects on PGO waves in the cat.

One of the phasic phenomena of REM (rapid eye movement) sleep, the ponto-geniculo-occipital (PGO) waves, are induced in cats by either depleting brain monoamines with the benzoquinolizine derivative Ro 4-1284 or inhibiting the synthesis of 5-hydroxy-tryptamine (5-HT) by p-chlorophenylalanine (PCPA). The effects of the most important psychotropic agents on PGO1284 and PGOPCPA are reported and explained by their interaction with one or more of the 4 neurotransmitters known so far to be involved in the regulation of the PGO wave generation in the pontine reticular formation. Tricyclic antidepressants depress PGO waves by inhibiting the neuronal uptake of norepinephrine (NE) and/or 5-HT. Some neuroleptics increase the density of GO waves by blocking 5-HT and/or NE receptors. Various indole hallucinogens depress PGO waves by stimulating 5-HT receptors. Benzoldiazepines appear to enhance a (gamma-aminobutyric acid)-ergic (GABA)-ergic inhibitory influence on NE neurons and increase the density of PGO waves in the presence of functionally intact NE neurons.