Summary
Tritium labelled gamma-aminobutyric acid (3H-GABA) was infused into the third ventricle of rats with normal or deafferented hypothalamus and the distribution of the label was studied by light and electron microscopic autoradiography.
In control as well as deafferented hypothalamus a few neurones accumulated radioactivity, while the majority was unlabelled. Characteristic clusters and rows of silver grains were observed in the neuropil of several regions probably indicating labelled cell processes and terminal axons. Electron microscopy showed that at least some of the clusters were over axon terminals with synaptic vesicles.
3H-GABA accumulated also in the ependyma and glial elements.
The results suggest that in the medial hypothalamus there is a preferential uptake of GABA in some neurones and nerve fibers; at least some of these are hypothalamic interneurones. This supports the hypothesis that some hypothalamic neurones and nerve endings may use GABA as a transmitter.
Similar content being viewed by others
References
Baldessarini, R.J., Karobath, M.: Biochemical physiology of central synapses. Ann. Rev. Physiol. 35, 273–304 (1973)
Collins, G.G.S.: GABA-2-Oxoglutarate transaminase, glutamate decarboxylase and the halflife of GABA in different areas of rat brain. Biochem. Pharmacol. 21, 2849–2858 (1972)
Fuxe, K., Hökfelt, T., Ritzen, M., Ungerstedt, U.: Studies on uptake of intraventricularly administrated tritiated noradrenaline and 5-hydroxytryptamine with combined fluorescence histochemical and autoradiographic techniques. Histochemie 16, 186–194 (1968)
Halász, B., Pupp, L.: Hormone secretion of the anterior pituitary gland after partial or total interruption of all nervous pathways to the hypophyseotrophic area. Endocrinology 77, 553–562 (1965)
Hattori, T., McGeer, P.L., Fibiger, H.C., McGeer, E.G.: On the source of GABA-containing terminals in the substantia nigra. Electron microscopic autoradiographic and biochemical studies. Brain Res. 54, 103–114 (1973)
Hökfelt, T., Johnson, G., Ljungdahl, Å.: Regional uptake and subcellular localization of (3H) gamma-aminobutyric acid (GABA) in rat brain slices. Life Sci. 9, 203–212 (1970)
Hökfelt, T., Ljungdahl, Å.: Autoradiographic identification of cerebral and cerebellar cortical neurons accumulating labeled gamma-aminobutyric acid (3H-GABA). Exp. Brain Res. 14, 354–362 (1972)
Hösli, E., Ljungdahl, Å., Hökfelt, T., Hösli, L.: Spinal cord tissue cultures —a model for autoradiographic studies on uptake of putative neurotransmitters such as glycine and GABA. Experientia (Basel) 28, 1342 (1972)
Iversen, L.L.: Role of transmitter uptake mechanisms in synaptic neurotransmission. Brit. J. Pharmacol. 41, 571–591 (1971)
Iversen, L.L., Bloom, F.E.: Studies of the uptake of 3H-GABA and (3H) glycine in slices and homogenates of rat brain spinal cord by electron microscopic autoradiography. Brain Res. 41, 131 (1972)
Ljungdahl, Å., Seiger, Å., Hökfelt, T., Olson, L.: (3H)-GABA uptake in growing cerebellar tissue: autoradiography of intraocular transplants. Brain Res. 61, 379–384 (1973)
Makara, G.B., Stark, E.: Effect of gamma-aminobutyric acid (GABA) and GABA antagonist drugs on ACTH release. Neuroendocrinology 16, 178–190 (1974)
Murphy, J.T., Renaud, L.P.: Inhibitory interneurons in the ventromedial nucleus of the hypothalamus. Brain Res. 9, 385–389 (1968)
Okada, Y., Nitsch-Hassler, C., Kim, J.S., Bak, I.J., Hassler, R.: Role of gamma-aminobutyric acid (GABA) in the extrapyramidal motor system. I. Regional distribution of GABA in rabbit, rat, guinea pig and baboon CNS. Exp. Brain Res. 13, 514–518 (1971)
Parizek, J., Hassler, R., Bak, I.J.: Light and electron microscopic autoradiography of substantia nigra of rat after intraventricular administration of tritium labelled norepinephrine, dopamine, serotonin and the precursors. Z. Zellforsch. 115, 137–148 (1971)
Schon, F., Iversen, L.L.: Selective accumulation of (3H) GABA by stellate cells in rat cerebellar cortex in vivo. Brain Res. 42, 503–507 (1972)
Schubert, P., Kreutzberg, G.W., Reinhold, K., Herz, A.: Selective uptake of 3H-6-hydroxydopamine by neurones of the central nervous system. Exp. Brain Res. 17, 539–548 (1973)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Makara, G.B., Rappay, G. & Stark, E. Autoradiographic localization of 3H-gamma-aminobutyric acid in the medial hypothalamus. Exp Brain Res 22, 449–455 (1975). https://doi.org/10.1007/BF00237347
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00237347