Expression and functional characterization of a melatonin-sensitive receptor in Xenopus oocytes.
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 micromol/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.
Fischer
B
B
Institut für Physiologie, Münster, Germany.
Musshoff
U
U
Fauteck
J D
JD
Madeja
M
M
Wittkowski
W
W
Speckmann
E J
EJ
D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D001345:Autoradiography; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D002110:Caffeine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D007700:Kinetics; D008550:Melatonin / Q000378:metabolism / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D008845:Microinjections; D009865:Oocytes / Q000502:physiology*; D018408:Patch-Clamp Techniques; D037342:Pertussis Toxin; D012333:RNA, Messenger / Q000008:administration & dosage / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000502:physiology*; D044094:Receptors, Melatonin; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000873:Anthracenes; D007457:Iodine Radioisotopes; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D044094:Receptors, Melatonin; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D002110:Caffeine; C010030:9-anthroic acid; D000242:Cyclic AMP; D037342:Pertussis Toxin; D008550:Melatonin