Expression and functional characterization of a melatonin-sensitive receptor in Xenopus oocytes

• Published in: FEBS letters 1996-02, Vol.381 (1), p.98-102
• Main Authors: Fischer, Bernhard, Muβhoff, Ulrich, Fauteck, Jan-Dirk, Madeja, Michael, Wittkowski, Werner, Speckmann, Erwin-Josef
• Format: Article
• Language: English
• Subjects: 9-AC, 9-anthracenecarboxylic acid; Animals; Anthracenes - pharmacology; Autoradiography; Binding Sites; Brain - metabolism; BSA, bovine serum albumine; Ca 2+-activated chloride current; Ca2+-activated chloride current; Caffeine - pharmacology; cAMP, cyclic adenosine 5′-monophosphate; Colforsin - pharmacology; Cyclic AMP - metabolism; DMSO, dimethyl sulfoxide; Female; Freshwater; G protein; G protein, guanyl nucleotide binding protein; HEPES, N-(2-hydroxyethyl)-piperazine-N′-2-ethane sulfonic acid; In Vitro Techniques; Iodine Radioisotopes; IP 3; IP3; IP3, inositol 1,4,5-triphosphate; Kinetics; MEL, melatonin; Melatonin; Melatonin - metabolism; Melatonin - pharmacology; Membrane Potentials - drug effects; Microinjections; Oocytes - physiology; Patch-Clamp Techniques; Pertussis Toxin; PTX, pertussis toxin; Rats; Receptors, Cell Surface - biosynthesis; Receptors, Cell Surface - physiology; Receptors, Melatonin; RNA, Messenger - administration & dosage; RNA, Messenger - metabolism; Tris, Tris(hydroxymethyl)aminomethane; Virulence Factors, Bordetella - pharmacology; Xenopus; Xenopus laevis; Xenopus oocyte
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(96)00090-7

Melatonin (MEL) plays a central role in the regulation of seasonal cycles and in the control of circadian rhythms in mammals. Functional MEL-sensitive receptors were expressed in Xenopus laevis oocytes following injection of poly (A) + RNA from rat brain. Administration of 0.1–100 μmol/l MEL to voltage-clamped oocytes (holding potential: −70 mV) elicited oscillatory inward currents (reversal potential: −24 mV) which could be blocked by 9-anthracenecarboxylic acid and caffeine. After preincubation with pertussis toxin (PTX) the MEL response disappeared. The expressed MEL-sensitive receptor probably activates Ca 2+-dependent chloride currents via a PTX-sensitive G protein and the phosphoinositol pathway.