The use of autoradiographic techniques for the identification and mapping of transmitter-specific neurones in the brain

Only in the case of the monoamine transmitters, noradrenaline (NA), dopamine (DA) and 5-hydroxytryptamine (5-HT) is there any detailed information on the distribution of neuronal pathways involving specific transmitters.

Abstract

We now know of at least six different transmitter substances used in synaptic transmission in the mammalian CNS, In most cases, however, only fragmentary information is available on the distribution of the various categories of transmitter-specific neurone in the CNS. Thus, for example, while gamma-aminobutyric acid (GABA) is thought to be an important inhibitory transmitter substance in many regions of the CNS (for reviews see Curtis and Johnston, 1970; Hebb, 1970; Krnjevic, 1970; Iversen, 1972), it is by no means clear precisely which inhibitory neurones use GABA as transmitter, nor indeed whether any inhibitory neurones using transmitters other than GABA exist in various regions of the brain. Only in the case of the monoamine transmitters, noradrenaline (NA), dopamine (DA) and 5-hydroxytryptamine (5-HT) is there any detailed information on the distribution of neuronal pathways involving specific transmitters. This information has become available during the past ten years, following the development of histochemical techniques which allow direct visualization of formaldehyde condensation derivatives of the monoamines in the fluorescence microscope (Carlsson, Falck and Hillarp, 1962; Dahlstrom and Fuxe, 1965; Fuxe, 1965).