Localization of L-glutamate receptors in rat brain by quantitative autoradiography

• Published in: The Journal of neuroscience Vol. 4; no. 9; pp. 2247 - 2258
• Main Authors: Halpain, S, Wieczorek, CM, Rainbow, TC
• Format: Journal Article
• Language: English
• Published: Washington, DC Soc Neuroscience 01-09-1984; Society for Neuroscience
• Subjects: Animals; Autoradiography; Binding Sites; Biological and medical sciences; brain; Brain - metabolism; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Densitometry; Fundamental and applied biological sciences. Psychology; In Vitro Techniques; L-glutamic acid; Male; Rats; Rats, Inbred Strains; Receptors, Glutamate; Receptors, Neurotransmitter - metabolism; Tissue Distribution; Vertebrates: nervous system and sense organs; Autoradiography; Vertebrata; Mammalia; Rat; Rodentia; Central nervous system; Brain (Vertebrata); Glutamate receptor; Localization
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/jneurosci.04-09-02247.1984

In vitro autoradiography was used to characterize and quantitatively map the sodium-independent binding of [3H]glutamate in rat brain. Measured in the presence of chloride, glutamate binding to frozen brain sections was specific, saturable, and reversible, with a Kd in the low micromolar range. At least two distinct binding sites were detected which had different affinities for quisqualic acid (0.7 microM and 1.2 mM). Autoradiograms revealed very high levels of binding in rostral forebrain areas, especially olfactory structures and frontal cortex. High levels of binding were found in sensory cortex, certain hippocampal subfields, caudate, lateral septum, and other limbic structures. Lowest levels were seen in globus pallidus, preoptic area, brainstem reticular formation, and spinal trigeminal nucleus. All other regions, including midbrain, thalamus, hypothalamus, and cerebellar cortex exhibited moderate levels of [3H]glutamate binding. Within the hippocampus glutamate binding was greatest in the inner two-thirds of the dentate molecular layer, subiculum, and CA1 stratum radiatum. CA3 was much less densely labeled; CA2 and CA4 were intermediate. Unlike cell layers in the cerebellum, hippocampal pyramidal and granule cell layers appeared mostly devoid of binding. The relationship of these binding sites to putative glutamate receptor subclasses and glutamatergic pathways is discussed.