Summary
Injections of the fluorescent dyes Fast Blue or Granular Blue into either the hippocampus (volume approximately 50 nl) or the entorhinal area (100–150 nl) resulted in labeling by retrograde axonal transport of cells in the diagonal band of Broca (dbB) and the medial septum (MS). A large number (approximately 30%) of these cells contained glutamic acid decarboxylase (GAD)-like immunoreactivity, as determined by combined retrograde fluorescent tracing and GAD-immunohistochemistry. Not all GAD positive cells in the dbB and MS were labeled by fluorochromes in a single experiment. The GAD-stained and fluorochrome-containing cells were present at all rostro-caudal levels of the septum and appeared not to belong to any single morphological class of cells. Double staining experiments showed that the GAD-positive cells did not contain acetylcholinesterase reaction product. These findings provide evidence that a significant portion of the septohippocampal projection may utilize gamma-aminobutyric acid as a neurotransmitter.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Alonso A, Köhler C (1982) Organization of the septo-entorhinal connections in the rat brain. Neuroscience 7:54 (Abstract)
Crutcher KA, Madison R, Davis JN (1981) A study of the rat septo-hippocampal pathway using anterograde transport of horseradish peroxidase. Neuroscience 6:1961–1973
Fonnum F, Walaas I (1978) The effect of intrahippocampal kainic acid injections and surgical lesions on neurotransmitters in hippocampus and septum. J Neurochem 31:1173–1181
Geneser-Jensen FA, Blackstad TW (1971) Distribution of acetylcholinesterase in the hippocampal region of the guinea pig. Entorhinal area, parasubiculum and presubiculum. Z Zellforsch 114:460–481
Harkmark W, Mellgren SI, Srebro B (1975) Acetylcholinesterase histochemistry of the septal region in the rat and human. Distribution of enzyme activity. Brain Res 95:281–289
Hökfelt T, Dahlström A (1971) Effects of two mitosis inhibitors (colchicine and vinblastine) on the distribution and axonal transport of noradrenaline storage particles studied by fluorescence and electron microscopy. Z Zellforsch 119:460–482
Köhler C, Chan-Palay V (1983) Distribution of gamma-aminobutyric acid containing neurons and terminals in the septal area. An immunohistochemical study using antibodies to glutamic acid decarboxylase in the rat brain. Anat Embryol 167:53–57
Köhler C, Steinbusch H (1982) Identification of serotonin and nonserotonin-containing neurons of the midbrain raphe projecting to the entorhinal area and the hippocampal formation. A combined immunohistochemical and fluorescent retrograde tracing study in the rat brain. Neuroscience 7:951–973
Mesulam MM, Van Hoesen GW (1976) Acetylcholinesterase-rich projections from the basal forebrain of the rhesus monkey to the neocortex. Brain Res 109:152–157
Oderfeld-Nowak B, Narkiewicz O, Bialowas J, Dabrowska J, Wieraszko A, Gradkowska M (1974) The influence of septal nuclei lesions on activity of acetylcholinesterase and choline acetyltransferase in the hippocampus of the rat. Acta Neurobiol Exp 34:787–789
Ropert N, Ben-Ari K, Krnjeric K, Pole P (1980) Septo-hippocampal pathway and cholinergic disinhibition of pyramidal cells. Can J Physiol 11:118
Sethy VH, Kuhar M, Roth RH, Van Woert MH, Aghajanian GK (1973) Cholinergic neurons: effect of acute septal lesions on acetylcholine and choline content of the rat hippocampus. Brain Res 55:481–484
Swanson LW, Cowan MW (1979) The connections of the septal region in the rat. J Comp Neurol 186:621–656
Wu J-Y, Matsuda T, Roberts E (1973) Purification and characterization of glutamic acid decarboxylase from mouse brain. J Biol Chem 248:3029–3034
Wyss JM, Swanson LW, Cowan MW (1979) A study of subcortical afferents to the hippocampal formation in the rat. Neuroscience 4:463–477
Author information
Authors and Affiliations
Additional information
This investigation was supported in part by USPHS grants NS 14740, NS 65392, NS 68462, and NS 67752; and AFOSR grant 82-0328
Rights and permissions
About this article
Cite this article
Köhler, C., Chan-Palay, V. & Wu, JY. Septal neurons containing glutamic acid decarboxylase immunoreactivity project to the hippocampal region in the rat brain. Anat Embryol 169, 41–44 (1984). https://doi.org/10.1007/BF00300585
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00300585