Anatomical evidence for glutamate and/or aspartate as neurotransmitters in the geniculo-, claustro-, and cortico-cortical pathways to the cat striate cortex.
Data obtained by using various experimental approaches suggest that in the mammalian brain, most neurons within the visual system projecting to the striate cortex employ excitatory amino acids as transmitters. In order to investigate further the neurotransmitter phenotype of the ipsilateral afferents to area 17 of the cat, we have injected D-[3H]-aspartate, a retrograde tracer which selectively reveals putative glutamatergic and/or aspartatergic pathways, into this area. Retrogradely labelled neurons were observed in the dorsal lateral geniculate nucleus, visual claustrum, cortical areas 18, 19, 21a, and in both posteromedial and posterolateral parts of the suprasylvian areas but not in other known thalamic afferents such as the lateral posterior-pulvinar complex and the intralaminar nuclei. The distribution and localization of the labelled cells in all these regions were similar to that observed by using the non-selective tracer horseradish peroxidase conjugated to wheat germ agglutinin, though the number of cells was higher with the latter. Our findings provide additional evidence for the presence of excitatory amino acids as neurotransmitters in the major afferents to the cat striate cortex.
Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Vizcaya, Spain. onppecef@lg.ehu.es
F
F
Pérez-Cerdá
L
L
Martínez-Millán
C
C
Matute
D000344:Afferent Pathways / Q000033:anatomy & histology; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D001479:Basal Ganglia / Q000033:anatomy & histology / Q000378:metabolism; D002415:Cats / Q000033:anatomy & histology* / Q000378:metabolism; D007839:Functional Laterality / Q000502:physiology; D005829:Geniculate Bodies / Q000033:anatomy & histology / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D014793:Visual Cortex / Q000033:anatomy & histology* / Q000378:metabolism; D014795:Visual Pathways / Q000033:anatomy & histology* / Q000378:metabolism; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate
D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D001224:Aspartic Acid; D018698:Glutamic Acid