Autoradiographic localization of putative nicotinic receptors in the rat brain using sup 125 I-neuronal bungarotoxin

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Journal of Neuroscience; (USA)

OSTI ID:6250167

Schulz, D W; Loring, R H; Aizenman, E; Zigmond, R E ^[1]

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1. Harvard Medical School, Boston, MA (USA)

Neuronal bungarotoxin (NBT), a snake venom neurotoxin, selectively blocks nicotinic receptors in many peripheral and central neuronal preparations. alpha-Bungarotoxin (alpha BT), on the other hand, a second toxin isolated from the venom of the same snake, is an ineffective nicotinic antagonist in most vertebrate neuronal preparations studied thus far. To examine central nicotinic receptors recognized by NBT, we have characterized the binding of 125I-labeled NBT (125I-NBT) to rat brain membranes and have mapped the distribution of 125I-NBT binding in brain sections using quantitative light microscopic autoradiography. The binding of 125I-NBT was found to be saturable, of high affinity, and heterogeneously distributed in the brain. Pharmacological studies suggested that more than one population of sites is labeled by 125I-NBT. For example, one component of 125I-NBT binding was also recognized by alpha BT, while a second component, not recognized by alpha BT, was recognized by the nicotinic agonist nicotine. The highest densities of these alpha BT-insensitive, nicotine-sensitive sites were found in the fasciculus retroflexus, the lateral geniculate nucleus, the medial terminal nucleus of the accessory optic tract, and the olivary pretectal nucleus. alpha BT-sensitive NBT binding sites were found in highest density in the lateral geniculate nucleus, the subthalamic nucleus, the dorsal tegmental nucleus, and the medial mammillary nucleus (lateral part). The number of brain regions with a high density of 125I-NBT binding sites, blocked either by alpha BT or by nicotine, is low when compared with results obtained using other approaches to studying the central distribution of nicotinic receptors, such as labeling with 3H-nicotine or labeling with cDNA probes to mRNAs coding for putative receptor subunits.

• OSTI ID: 6250167
• Journal Information: Journal of Neuroscience; (USA), Journal Name: Journal of Neuroscience; (USA) Vol. 11:1; ISSN JNRSD; ISSN 0270-6474
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALOIDS
AMINES
ANTIGENS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
AZINES
AZOLES
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
BODY
BRAIN
CELL CONSTITUENTS
CELL MEMBRANES
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HETEROCYCLIC COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
MATERIALS
MEMBRANE PROTEINS
MEMBRANES
NERVOUS SYSTEM
NICOTINE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PARASYMPATHOLYTICS
PARASYMPATHOMIMETICS
PROTEINS
PYRIDINES
PYRROLES
PYRROLIDINES
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
TOXIC MATERIALS
TOXINS