title: Involvement of melatonin metabolites in the long-term inhibitory effect of the hormone on rat spinal nociceptive transmission.
abstract: There is evidence that melatonin and its metabolites could bind to nuclear sites in neurones, suggesting that this hormone is able to exert long-term functional effects in the central nervous system via genomic mechanisms. This study was designed to investigate (i) whether systemically administered melatonin can exert long-term effects on spinal cord windup activity, and (ii) whether blockade of melatonin degradation with eserine could prevent this effect. Rats receiving melatonin (10 mg/kg ip), the same dose of melatonin plus eserine (0.5 mg/kg ip), or saline were studied. Seven days after administration of the drugs or saline, spinal windup of rats was assessed in a C-fiber reflex response paradigm. Results show that rats receiving melatonin exhibited a reduction in spinal windup activity. This was not observed in the animals receiving melatonin plus eserine or saline, suggesting a role for melatonin metabolites in long-term changes of nociceptive transmission in the rat spinal cord.
authors.affiliation: Institute of Nutrition and Food Technology (INTA), University of Chile, P.O. Box 138-11, Santiago, Chile.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Mondaca
authors.forename: Alejandro
authors.initials: A
authors.lastname: Hernández
authors.forename: Luis
authors.initials: L
authors.lastname: Valladares
authors.forename: Walter
authors.initials: W
authors.lastname: Sierralta
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Noseda
authors.forename: Rubén
authors.initials: R
authors.lastname: Soto-Moyano
mesh_terms: D008735:5-Methoxytryptamine / Q000378:metabolism; D000581:Amidohydrolases / Q000037:antagonists & inhibitors; D000818:Animals; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004558:Electric Stimulation; D008297:Male; D008550:Melatonin / Q000378:metabolism* / Q000494:pharmacology*; D036421:Nerve Fibers, Unmyelinated / Q000187:drug effects; D009619:Nociceptors / Q000187:drug effects*; D010830:Physostigmine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000187:drug effects; D013116:Spinal Cord / Q000187:drug effects* / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects*
chemical_list: D002800:Cholinesterase Inhibitors; D008735:5-Methoxytryptamine; D010830:Physostigmine; D000581:Amidohydrolases; C072890:melatonin deacetylase; C019665:amidase; D008550:Melatonin