Biomaterial Database

2-[125I]iodomelatonin binding sites in the rat vas deferens. 1993

R C Carneiro, and R P Markus, and M L Dubocovich

Department of Pharmacology, Northwestern University Medical School, Chicago, Ill. 60611.

To further understand the mechanism by which melatonin potentiates noradrenergic transmission in the rat vas deferens, we localized and partially characterized 2-[125I]-iodomelatonin-binding sites in tissue sections of the rat vas deferens using quantitative autoradiography. High-affinity 2-[125I]-iodomelatonin-binding sites were localized around the lumen of the prostatic portion, but not in the epididymal portion of the rat vas deferens. The binding of 2-[125I]-iodomelatonin to sections of the prostatic portion was stable, reversible and saturable. Saturation studies revealed a single class of high-affinity binding sites with a dissociation constant (Kd) of 104.2 +/- 23.7 pM (n = 4) and a binding capacity (Bmax) of 2.07 +/- 0.19 fmol/mg of protein (n = 4). These results suggest that melatonin may regulate sympathetic neurotransmission through activation of specific melatonin receptors in the prostatic portion of the rat vas deferens.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D008297	Male		Males
D008550	Melatonin	A biogenic amine that is found in animals and plants. In mammals, melatonin is produced by the PINEAL GLAND. Its secretion increases in darkness and decreases during exposure to light. Melatonin is implicated in the regulation of SLEEP, mood, and REPRODUCTION. Melatonin is also an effective antioxidant.
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001345	Autoradiography	The making of a radiograph of an object or tissue by recording on a photographic plate the radiation emitted by radioactive material within the object. (Dorland, 27th ed)	Radioautography
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D014649	Vas Deferens	The excretory duct of the testes that carries SPERMATOZOA. It rises from the SCROTUM and joins the SEMINAL VESICLES to form the ejaculatory duct.	Ductus Deferens,Deferens, Ductus,Deferens, Vas
D044094	Receptors, Melatonin	A family of G-protein-coupled receptors that are specific for and mediate the effects of MELATONIN. Activation of melatonin receptors has been associated with decreased intracellular CYCLIC AMP and increased hydrolysis of PHOSPHOINOSITIDES.	Melatonin Receptors,MT3 Receptor,Mel(1c) Receptor,Melatonin MT3 Receptor,Receptor, Mel1c,Receptor, Melatonin,Receptor, Melatonin, 1C,Receptor, Melatonin, MT3,MT3 Receptor, Melatonin,Mel1c Receptor,Melatonin Receptor,Receptor, MT3,Receptor, Melatonin MT3
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus