title: Melatonin increases cGMP and decreases cAMP levels in rat medial basal hypothalamus in vitro.
abstract: Measurement of cyclic nucleotide accumulation in rat medial basal hypothalamus (MBH) incubated in vitro with methoxyindoles indicated that melatonin (10(-8) M or greater) increased significantly cGMP and depressed cAMP levels. Only the effect on MBH cAMP was shared by 5-methoxytryptophol which exhibited a greater activity than melatonin. 6-Fluoromelatonin (10(-7) M) increased cGMP, whereas the effect of 6-hydroxymelatonin was not significant. Both 6-fluoro- and 6-hydroxymelatonin (10(-5) M) depressed MBH cAMP accumulation while only 6-fluoromelatonin affected it at 10(-7) M concentrations. These data suggest that melatonin and 5-methoxytryptophol affect differently cyclic nucleotide content of MBH at physiological concentrations.
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000242:Cyclic AMP; D006152:Cyclic GMP; D008550:Melatonin