Summary
The distribution of (125I) alpha bungarotoxin (α-BTX) binding sites in the suprachiasmatic nucleus (SCN) of the adult female rat was examined by electron-microscopic autoradiography. The ultrastructural distribution of silver grains was analysed by line source, direct point count, and 50% probability circle methods. Real grain distribution was significantly different from that of randomly generated hypothetical grains. Line source analysis demonstrated two populations of sources: one associated with membranes, and one inside neuronal structures. Probability circle analysis of shared grains indicated that membrane-bound-radioactive sources were mainly asssociated with axo-dendritic appositions. Only a small proportion of labeled neuronal interfaces exhibited synaptic differentiations in the plane of section. However, the compartment containing synaptic terminals was the most enriched when comparing real to hypothetical grains. Probability circle analysis of exclusive grains demonstrated that sources that were not associated with neuronal plasma membranes were likely to be within nerve cell bodies and dendrites. It is concluded that the majority of specifically labeled α-BTX binding sites in the SCN is membrane bound, and may be associated with axodendritic synaptic transmission. The presence of a significant proportion of the label in the soma and dendrites of suprachiasmatic neurons 24 h after ventricular infusion suggests that some of the labeled binding sites (junctional or nonjunctional) may be internalized within these two compartments.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Arimatsu Y, Seto A, Amano T (1978) Localization of α-bungarotoxin binding sites in mouse brain by light and electron microscopic autoradiography. Brain Res 147:165–169
Bourgeois J-P, Ryter A, Menez A, Fromagegeot P, Changeux J-P (1972) Localization of the cholinergic receptor protein in Electrophorous electroplax by high resolution autoradiography. FEBS Lett 25:127–133
Brownstein MJ, Kobayashi R, Palkovits M, Saavedra JM (1975) Choline acetyltransferase levels in diencephalic nuclei of the rat. J Neurochem 24:35–38
Chiappinelli VA, Giacobini E (1978) Time course of appearance of α-bungarotoxin binding sites during development of chick ciliary ganglion and iris. Neurochem Res 3:465–478
Chiappinelli VA, Cohen JB, Zigmond RE (1981) The effect of α- and β-neurotoxins from the venom of various snakes on transmission in autonomic ganglia. Brain Res 211:107–126
Clarke PBS, Schwartz RD, Paul SM, Pert CB, Pert A (1985) Nicotinic binding in the rat brain: autoradiographic comparison of (3H) acetylcholine, (3H) nicotine, and (125I) α-bungarotoxin. Neuroscience 5:1307–1315
Conti-Tronconi BM, Dunn SM, Barnard EA, Dolly JO, Lai FA, Roy N, Raftery MA (1985) Brain and muscle nicotinic acetylcholine receptors are different but homologous proteins. Proc Natl Acad Sci USA 82:5208–5212
Dun NJ, Karczmar AJ (1980) Blockade of ACh potentials by α-bungarotoxin in rat superior cervical ganglion cells. Brain Res 196:536–540
Fambrough DM (1979) Control of acetylcholine receptors in skeletal muscle. Physiol Rev 59:165–227
Fertuck HC, Salpeter MM (1976) Quantitation of junctional and extrajunctional acetylcholine receptors by electron microscope autoradiography after (125I)-α-bungarotoxin binding at mouse neuromuscular junctions. J Cell Biol 69:144–158
Fumagalli L, de Renzis G (1984) Extrasynaptic localization of α-bungarotoxin receptors in the rat superior cervical ganglion. Neurochem Int 6:355–364
Hunt SP, Schmidt J (1978) The electron microscopic autoradiographic localization of α-bungarotoxin binding sites within the central nervous system of the rat. Brain Res 142:152–159
Ichikawa T, Hirata Y (1986) Organization of choline acetyltransferase-containing structures in the forebrain of the rat. J Neurosci 6:281–292
Jacob MH, Berg DK (1983) The ultrastructural localization of α-bungarotoxin binding sites in relation to synapses on chick ciliary ganglion neurons. J Neurosci 3:260–271
Kow K-M, Pfaff DW (1984) Suprachiasmatic neurons in tissue slices from ovariectomized rats: electrophysiological and neuropharmacological characterization and effects of estrogen treatment. Brain Res 297:275–286
Lentz TL, Chester J (1977) Localization of acetylcholine receptors in central synapses. J Cell Biol 75:258–267
Loring RH, Dahm LM, Zigmond RE (1985) Localization of α-bungarotoxin binding sites in the ciliary ganglion of the embryonic chick: and autoradiographic study at the light and electron microscopic level. Neuroscience 14:645–660
Mason WT (1985) Staining of the magnocellular nuclei of the rat hypothalamus of a monoclonal antibody directed against the α-subunit of the nicotinic cholinergic receptor. Neurosci Lett 59:89–95
Messing A, Gonates NK (1983) Extra-synaptic localization of α-bungarotoxin receptors in cultured chick ciliary ganglion neurons. Brain Res 269:172–176
Miller MM, Billiar RB (1986) A quantitative and morphometric evaluation of (125I) α-bungarotoxin binding components in the rat hypothalamus. Brain Res Bull 16:681–688
Miller MM, Silver J, Billiar RB (1982) Effects of ovariectomy on the binding of (125I) α-bungarotoxin (2.2 and 3.3) to the suprachiasmatic nucleus of the hypothalamus: an in vivo autoradiographic analysis. Brain Res 247:355–364
Miller MM, Silver J, Billiar RB (1984) Effects of gonadal steroids on the in vivo binding of (125I) α-bungarotoxin to the suprachiasmatic nucleus. Brain Res 290:67–75
Morley BJ, Kemp GE (1981) Characterization of a putative nicotinic acetylcholine receptor in mammalian brain. Brain Res 3:81–104
Noshino H, Koizumi K (1977) Responses of neurons in the suprachiasmatic nuclei of the hypothalamus to putative transmitters. Brain Res 120:167–172
Oswald RE, Freeman JA (1981) α-Bungarotoxin and central nervous system nicotinic acetylcholine receptors. Neuroscience 6:1–14
Pellegrino LJ, Pellegrino AS, Cushman AJ (1979) A stereotaxic atlas of the rat brain. Plenum Press, New York
Polz-Tejera G, Hunt SP, Schmidt J (1980) Nicotinic receptors in sensory ganglia. Brain Res 195:223–230
Quik M (1982) Presence of an endogenous factor which inhibits binding of α-bungarotoxin 2.2 to its receptor. Brain Res 245:57–67
Ravdin PM, Berg DK (1976) Inhibition of neuronal acetylcholine sensitivity by α-toxins from Bungarus multicinctus venom. Proc Natl Acad Sci USA 76:2072–2076
Ravdin PM, Nitkin RM, Berg DK (1981) Internalization of α-bungarotoxin on neurons induced by a neurotoxin that blocks neuronal acetylcholine sensitivity. J Neurosci 1:849–861
Salpeter MM, McHenry FA, Salpeter EE (1978) Resolution of electron microscope autoradiography. IV. Application to analysis of autoradiographs. J Cell Biol 76:127–145
Schmidt J, Hunt S, Polz-Tejera G (1980) Nicotinic receptors of the central and autonomic nervous system. In: Eissman WB (ed) Neurotransmitters, receptors, and drug action. Spectrum Publications, New York, pp 1–45
Schwartz R (1986) Autoradiographic distribution of high affinity muscarinic and nicotinic cholinergic receptors labeled with (3H) acetylcholine in rat brain. Life Sci 38:2111–2119
Smolen AJ (1983) Specific binding of α-bungarotoxin to synaptic membranes in rat sympathetic ganglion: computer best-fit analysis of electron microscope radioautographs. Brain Res 289:177–188
Williams MA (1969) The assessment of electron microscopic autoradiographs. Adv Opt Elect Microsc 3:219–272
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Miller, M.M., Billiar, R.B. & Beaudet, A. Ultrastructural distribution of alpha-bungarotoxin binding sites in the suprachiasmatic nucleus of the rat hypothalamus. Cell Tissue Res. 250, 13–20 (1987). https://doi.org/10.1007/BF00214648
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00214648