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Neurotransmitter Receptor Ligand Binding and Enzyme Regional Distribution in the Pigeon Visual System
Author(s) -
Vischer A.,
Cuenód M.,
Henke H.
Publication year - 1982
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1982.tb07915.x
Subject(s) - glutamate decarboxylase , choline acetyltransferase , neuroscience , biology , dopaminergic , medicine , endocrinology , chemistry , dopamine , cholinergic , biochemistry , enzyme
The relative importance of acetylcholine, dopamine, endogenous opiates, γ‐aminobutyric acid (GABA), glutamate, glycine, noradrenaline, and serotonin as transmitters in the pigeon visual system was estimated by measuring the activity of choline acetyltransferase (ChAT), glutamic acid decarboxylase (GAD), and aromatic amino acid decarboxylase (AAD) as well as the binding of dihydroalprenolol, etorphine, kainic acid, muscimol, serotonin, spiroperidol, strychnine, and quinuclidinyl benzilate (QNB) in the tectum opticum, nucleus rotundus, ectostriatum, dorsolateral thalamus, and hyperstriatum (Wulst). As a nonvisual reference structure, the paleostriatal complex was included in the examination. The regional distribution of most of these parameters was very similar to data reported in the mammalian CNS supporting the hypothesis that the avian tectofugal and thalamofugal visual systems are homologous to the mammalian tecto‐thalamo‐cortical and retinogeniculo‐striate pathways, respectively. On the basis of the low values of their parameters, some transmitters can be excluded as significant contributors in a number of structures. As a hypothesis for further investigations, the presence of cholinergic and serotoninergic systems in the Wulst, possibly originating in the dorsolateral thalamus and nucleus raphe, respectively, and of glycinergic and dopaminergic terminals in the paleostriatal complex is proposed.