Constitutively active melatonin MT(1) receptors in male rat caudal arteries.
This study assessed the state of melatonin MT(1) receptor coupling in sections of male rat caudal arteries by [35S]GTPgammaS binding autoradiography. The melatonin MT(1) receptor inverse agonist 4-phenyl-2-propionamidotetraline (4P-PDOT) (0.1-1 microM) significantly decreased [35S]GTPgammaS binding compared to basal, strongly suggesting the presence of constitutively active receptors. Formation of constitutively active receptors during subjective day, when the levels of melatonin are low, may be a physiological mechanism by which the organism maintains vascular tone.
Erşahin
Cağatay
C
Department of Molecular Pharmacology and Biological Chemistry (S215), Northwestern University Medical School, 303 East Chicago Avenue, Chicago, IL 60611, USA.
Masana
Monica I
MI
Dubocovich
Margarita L
ML
D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000378:metabolism*; D001345:Autoradiography; D001667:Binding, Competitive / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D008297:Male; D008550:Melatonin / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D044094:Receptors, Melatonin; D013462:Sulfur Radioisotopes; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
C114459:4-phenyl-2-propionamidotetraline; D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; D044094:Receptors, Melatonin; D013462:Sulfur Radioisotopes; D013764:Tetrahydronaphthalenes; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D008550:Melatonin