Quantitative autoradiography of muscarinic and benzodiazepine receptors in the forebrain of the turtle, Pseudemys scripta

Journal Article · Sat Nov 21 23:00:00 EST 1987 · J. Comp. Neurol.; (United States)

DOI:https://doi.org/10.1002/cne.902650406· OSTI ID:5445951

Schlegel, J R; Kriegstein, A R

The distribution of muscarinic and benzodiazepine receptors was investigated in the turtle forebrain by the technique of in vitro receptor autoradiography. Muscarinic binding sites were labeled with 1 nM /sup 3/H-quinuclidinyl benzilate (/sup 3/H-QNB), and benzodiazepine sites were demonstrated with the aid of 1 nM /sup 3/H-flunitrazepam (/sup 3/H-FLU). Autoradiograms generated on /sup 3/H-Ultrofilm apposed to tissue slices revealed regionally specific distributions of muscarinic and benzodiazepine binding sites that are comparable with those for mammalian brain. Dense benzodiazepine binding was found in the anterior olfactory nucleus, the lateral and dorsal cortices, and the dorsal ventricular ridge (DVR), a structure with no clear mammalian homologue. Muscarinic binding sites were most dense in the striatum, accumbens, DVR, lateral geniculate, and the anterior olfactory nucleus. Cortical binding sites were studied in greater detail by quantitative analysis of autoradiograms generated by using emulsion-coated coverslips. Laminar gradients of binding were observed that were specific for each radioligand; /sup 3/H-QNB sites were most dense in the inner molecular layer in all cortical regions, whereas /sup 3/H-FLU binding was generally most concentrated in the outer molecular layer and was least dense through all layers in the dorsomedial cortex. Because pyramidal cells are arranged in register in turtle cortex, the laminar patterns of receptor binding may reflect different receptor density gradients along pyramidal cell dendrites.

• Research Organization: Stanford Univ. School of Medicine, CA (USA)
• OSTI ID: 5445951
• Journal Information: J. Comp. Neurol.; (United States), Journal Name: J. Comp. Neurol.; (United States) Vol. 265:4; ISSN JCNEA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CELL CONSTITUENTS
CELL NUCLEI
CENTRAL NERVOUS SYSTEM
CHOLINE
DRUGS
HYDROXY COMPOUNDS
IN VITRO
KINETICS
LABELLED COMPOUNDS
LIGANDS
LIPOTROPIC FACTORS
MEMBRANE PROTEINS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
PROTEINS
QUATERNARY COMPOUNDS
REACTION KINETICS
RECEPTORS
REPTILES
SYMPATHOLYTICS
TRITIUM COMPOUNDS
TURTLES
VERTEBRATES