Melatonin (MEL), the principle secretory product of the pineal gland, has been shown to function as an antioxidant and free-radical scavenger. We previously showed that the release of ascorbic acid (AA) and luteinizing hormone releasing hormone (LHRH) from medial basal hypothalamus (MBH) was mediated by nitric oxide (NO) that released cyclic guanosine 3′5′-monophosphate (cGMP). Therefore, it was of interest to evaluate the effect of MEL on AA and LHRH release and study the effect of a nitric oxide synthase (NOS) inhibitor, 6-anilino-5,8-quinolinedione (LY 83583), and a guanylyl cyclase (GC) inhibitor, 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (O.D.Q.), on the release process. Because NO has been shown to activate soluble guanylyl cyclase that elicited an elevation of cGMP in target cells, in the current investigation LY 83583, O.D.Q., or NG-monomethyl-L-arginine (NMMA), a competitive inhibitor of NOS, were used to evaluate their effects on MEL-induced AA and LHRH release. Medial basal hypothalami were incubated in 0.5 ml of Krebs-Ringer bicarbonate (KRB) buffer for 1 hr. Subsequently, the tissues were incubated with graded concentrations of MEL (10−8 to 10−4 M), MEL + NMMA (3 × 104 M), MEL + LY 83583 (10−6 M), or MEL + O.D.Q. (105 M) for 1 hr. Ascorbic acid and LHRH released into the medium were measured by high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA), respectively. Melatonin (10−6 and 105 M) significantly stimulated both AA and LHRH release, but the lower and the highest concentrations were ineffective. A combination of MEL + NMMA completely blocked both AA and LHRH release, supporting a role for NO in the releasing action. Both LY 83583 and O.D.Q. significantly suppressed MEL-induced AA and LHRH release, emphasizing the role of NOS, GC, and cGMP in mediating the action of MEL. The data of these in vitro experiments support a role for MEL in the hypothalamic control of AA and LHRH release.
LernerAB, CaseJD, TakahashiY, LeeTH, MoriW. Isolation of melatonin, the pineal factor that lightens melanocytes. J Am Chem Soc80: 2587, 1958.
2.
HastingsMH, VanceG, MaywoodE. Some reflections on the physiology and function of the pineal. Experientia45: 903–909, 1989.
3.
ReiterRJ. Pineal melatonin: cell biology of its synthesis and of its physiological interactions. Endocrinol Rev12: 151–180, 1991.
4.
ZawilskaJB, NovakJZ. Regulatory mechanisms in melatonin biosynthesis in retina. Neurochem Int20: 23–36, 1992.
5.
PangSF, AllenAE. Extra pineal melatonin in the retina: its regulation and physiological function. Pineal Res Rev4: 55–95, 1986.
6.
HuetherG. The contribution of extrapineal sites of melatonin synthesis to circulating melatonin levels in higher vertebrates. Experientia49: 665–670, 1993.
7.
ReiterRJ. Pineal function during aging, attenuation of the melatonin rhythm and its neurological consequences. Acta Neurobiol Exp54(Suppl): 31–39, 1994.
8.
NowakJZ, ZurawskaE, ZawilskaJ. Melatonin and its generating system in vertebrate retina: circadian rhythm, effects of environmental lighting and interaction with dopamine. Neurochem Int14: 397–406, 1989.
9.
BinkleyS, HryshchyshynM, ReillyK. N-acetyl transferase activity responds to environmental lighting in the eye as well as in the pineal gland. Nature281: 479–481, 1979.
10.
ShidaCS, CastrucciAML, Lamy-FreundMT. High melatonin solubility in acqueous medium. J Pineal Res16: 198–201, 1994.
11.
CostaEJ, LopezRH, Lamy-FreundMT. Permeability of pure lipid bilayers to melatonin. J Pineal Res19: 123–126, 1995.
12.
Mennendez-PelaezAB, PoeggelerB, ReiterRJ, Burlow-WaldenL, PablosMI, TanDX. Nuclear localization of melatonin in different mammalian tissues: immunocytochemical and radioimmunoassay evidence. J Cell Biochem53: 572–582, 1993.
13.
Mennendez-PelaezAB, ReiterRJ. Distribution of melatonin in mammalian tissues: the relative importance of nuclear verses cytosolic localizations. J Pineal Res15: 59–69, 1993.
14.
TanDX, PoeggelerB, ReiterRJ, ChenLD, ChenS, ManchesterLC, Barlow-WaldenLR. The pineal hormone melatonin inhibits DNA-adduct formation induced by the chemical carcinogen safrole in vivo. Cancer Lett70: 65–71, 1993.
15.
ReiterRJ, PablosMI, AgapitoTT, GuerreroJM. Melatonin in the context of free radical theory of aging. Ann N Y Acad Sci786: 362–378, 1996.
16.
ReiterRJ, TangL, GarciaJJ, Munoz-HoyosA. Pharmacological actions of melatonin in oxygen radical patho-physiology. Life Sci60: 2255–2271, 1997.
17.
ReiterRJ, Acuna-CastroviojoD, TanDX, BurkhardtS. Free radical mediated molecular damage, mechanism for the protective actions of melatonin in the central nervous system (review). Ann N Y Acad Sci939: 200–215, 2001.
18.
HardelandR, ReiterRJ, PoeggelerB, TanDX. The significance of the metabolism of the neurohormone melatonin: auto-oxidative protection and formation of bioactive substances. Neurosci Biobehav Rev17: 347–357, 1993.
GiladE, CuzzocreaS, ZingarelliB, SalzmanAL, SzaboC. Melatonin is a scavenger of peroxynitrite. Life Sci60: 169–174, 1998.
21.
ZangLY, CosmaG, GardnerH, VallyathanV. Scavenging of reactive oxygen species by melatonin. Biochem Biophys Acta1425: 469–477, 1998.
22.
PangSF, PangCS, PanAMS, ShiuSWY, SongY, LeePPN, ShoY, LiuZM. Pineal melatonin and its receptors in humans. In: TangPL, PangSF, ReiterRJ, Eds. Melatonin: A Universal Periodic Signal with Diverse Actions. Basal: Karger, Vol 21:pp 133–146, 1996.
23.
CaroleoMC, FrascaD, NisticoG, DoriaG. Melatonin as immunomodulator in immuno deficient mice. Immunopharmacology23: 81–89, 1992.
24.
ViswanathanM, LaitinenJT, SaavedraJM. Expression of melatonin receptors in arteries involved in thermoregulation. Proc Natl Acad Sci USA87: 6200–6203, 1990.
PierpaoliW, RegelsonW. Pineal control of aging: effect of melatonin and pineal grafting on aging mice. Proc Natl Acad Sci U S A91: 787–791, 1994.
27.
LincolnGA, MaedaK. Reproductive effects of placing micro-implants of melatonin in the mediobasal hypothlamus and preoptic area in rams. J Endocrinol132: 201–215, 1992.
28.
MalpauxB, DaveauA, MauriceF, GayrardV, ThieryJC. Short day effects of melatonin on luteinizing hormone secretion in the ewe: evidence for central sites of action in the mediobasal hypothalamus. Biol Reprod48: 752–760, 1993.
29.
DuncanWJ, TakahashiJS, DubokovitchML. Characteristics and autoradiographic localization of I 125 Iodomelatonin binding sites in Djungarian hamster brain. Endocrinology125: 1011–1018, 1989.
30.
WilliamsLM, MorganPJ, HastingsMH, LawsonW, DavidsonG, HowellE. Melatonin receptor sites in the Syrian hamster brain and pituitary. Localization and characterization using I125 Iodomelatonin. J Neuroendocrinology1: 315–320, 1989.
AyreEA, PangSF. I-[125] Iodomelatonin binding sites in the testis and ovary. Putative melatonin receptors in the gonads. Biol Signals3: 71–84, 1994.
33.
WeaverDR, ReppertSM. The melatonin receptor gene is expressed in human suprachiasmatic nuclei. Neureport8: 109–112, 1996.
34.
PioliC, CarleoMC, NisticoG, DoriaG. Melatonin increases antigen presentation and amplifies specific and non specific signals for T-cell proliferation. Int J Immunopharmacol15: 463–468, 1993.
35.
HaiderC, SinghR. Pineal modulation of thymus and immune function in a seasonally breeding tropical rodent Funambulus Pennanti. J Exp Zool289: 90–98, 2001.
36.
WeaverDR, ReppertSM, RivkeesSA, StopaEG. Putative melatonin receptors in a human biological clock. Science242: 78–81, 1988.
37.
MorganPJ, WilliamsLM, DavidsonG, LawsonW, HowellE. Melatonin receptors on ovine pars tuberalis: characterization and autoradiographical localization. J Neuroendocrinology1: 1–4, 1989.
38.
FitzgeraldKT. The structure and function of the pars tuberalis of the vertebrate adenohypophysis. Gen Comp Endocrinology37: 383–399, 1979.
39.
NakazawaK, MarubayashiU, McCannSM. Mediation of the short-loop negative feedback of luteinizing hormone (LH) on LH releasing hormone release by melatonin-induced inhibition of LH release from the pars tuberalis. Proc Natl Acad Sci U S A88: 7576–7579, 1991.
40.
MahalHS, SharmaHS, MukherjeeT. Antioxidant properties of melatonin: a pulse radiolysis study. Free Rad Biol Med26: 557–565, 1999.
41.
KaranthS, YuWH, WalczewskaA, MastronardiCA, McCannSM. Ascorbic acid acts as an inhibitory transmitter in the hypothalamus to inhibit stimulated luteinizing hormone-releasing hormone release by scavenging nitric oxide. Proc Natl Acad Sci U S A97: 1891–1896, 2000.
42.
KamagaiY, MidorikawaK, NakaiY, YoshikawaT, KushidaK, Homma-TakedaS, ShimojoN. Inhibition of nitric oxide formation and superoxide generation during reduction of LY 83583 by neuronal nitric oxide synthase. Eur J Pharmacol360: 213–218, 1998.
43.
GarthwaiteJ, SouthanE, BoultonCL, NielsenEB, SchmidtK, MayerB. Potent and selective inhibition of nitric oxide sensitive guanylyl cyclase by 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one. Mol Pharmacol48: 184–188, 1995.
44.
HarapanhalliRS, HowellRW, RaoDV. Testicular and plasma ascorbic acid levels in mice following dietary intake, a high performance liquid chromatographic analysis. J Chromatography614: 233–243, 1993.
45.
DluzenDE, RamirezVD. In vivo activity of the LHRH pulse generator as determined with push-pull perfusion of the anterior pituitary gland of unrestrained intact and castrate male rats. Neuroendocrinology45: 328–332, 1987.
46.
KaoLW, WeiszJ. Release of gonadotrophin-releasing hormone (GnRH) from isolated, perifused and medial-basal hypothalamus by melatonin. Endocrinology100: 1723–1726, 1977.
47.
BigdeliH, SnyderPJ. Gonadotropin releasing hormone release from the rat hypothalamus: dependence on membrane depolarization and calcium influx. Endocrinology103: 281–286, 1978.
48.
RichardsonSB, PrasadJA, HollanderCS. Acetylcholine, melatonin and potassium depolarization stimulate release of luteinizing hormone-releasing hormone from rat hypothalamus in vitro. Proc Natl Acad Sci USA79: 2681–2689, 1982.
49.
MessagerS, CaillolM, MartnetL. Long-term exposure of hypothalamic expiants to melatonin alters the release of gonadotropin releasing hormone and the density of melatonin binding sites in the pars tuberalis of the male mink (Mustek vison). J Pineal Res26: 17–27, 1999.
50.
DubosovichML. Pharmacology and function of melatonin receptors. FASEB J2: 2766–2773, 1988.
MahachoklertwattanaP, BlackSM, KaplanSL, BristowJD, GrumbachMM. Nitric oxide synthesized by gonadotropin releasing hormone neurons is a mediator of N-methyl-D-aspartate (NMDA) induced GnRH secretion. Endocrinology135: 1709–1712, 1994.
57.
RettoriV, BelovaN, DeesWJ, NybergCI, GimenoM, McCannSM. Role of nitric oxide in the control of luteinizing hormone releasing hormone release in vitro. Proc Natl Acad Sci U S A90: 11543–11546, 1993.
58.
PalmerRM, FerrigeAG, MoncadaS. Nitric oxide release accounts for the biological activity of endothelium derived relaxing factor. Nature327: 524–526, 1987.
59.
SchumannEM, MadisonDV. Nitric oxide and synaptic function. Ann Rev Neuro17: 153–183, 1994.
60.
GarthwaiteJ, CharlesSJ, Chess-WilliamsR. Endothelium-derived relaxing factor release on activation of NMDA receptor suggests role as intercellular messenger in the brain. Nature336: 385–388, 1988.
KnowlesRG, PalaciosM, PalmerRM, MoncadaS. Formation of nitric oxide from L-arginine in the central nervous system: a transduction mechanism for stimulation of the soluble guanylyl cyclase. Proc Natl Acad Sci U S A86: 5159–5162, 1989.
63.
DawsonTM, SnyderSH. Gases as biological messengers: nitric oxide and carbon monoxide in the brain. J Neurosci14: 5147–5159, 1994.
64.
BredtDS, SnyderSH. Isolation of nitric oxide synthase, a calmodulin requiring enzyme. Proc Natl Acad Sci U S A87: 682–685, 1994.
65.
LamasS, MarsdenPA, LiGK, TempstP, MichelT. Endothelial nitric oxide synthase: molecular cloning and characterization of a distinct constitutive enzyme isoform. Proc Natl Acad Sci U S A89: 6348–6352, 1992.
66.
BhatGK, MaheshVB, LamarCA, PingL, AguanK, BrannDW. Histochemical localization of nitric oxide neurons in the hypothalamus: association with gonadotropin releasing hormone neurons and colocalization with N-methyl-D-aspartate receptors. Neuroendocrinology62: 187–197, 1995.
67.
BettahiI, PozoD, OsunaC, ReiterRJ, Acuna-CastroviegoD, and GuerreroJM. Melatonin reduces nitric oxide synthase activity in rat hypothalamus. J Pineal Res20: 205–210, 1996.
68.
BettahiI, GuerreroJM, ReiterRJ, OsunaC. Physiological concentrations of melatonin inhibit the norepinephrine induced activation of E2 and cyclic AMP production in rat hypothalamus: a mechanism involving inhibition of nitric oxide synthase. J Pineal Res25: 34–40. 1998.
69.
PozoD, ReiterRJ, CalvoJR, GuerreroJM. Physiological concentrations of melatonin inhibit the nitric oxide synthase in rat cerebellum-Life Sci55: 455–460, 1994.
70.
DiamondJ, ChuEB. A novel cyclic GMP-lowering agent LY 83583, blocks carbachol-induced cyclic GMP elevation in rabbit atrial strips without blocking the negative ionotropic effects of carbachol. Can J Physiol Pharmacol68: 908–911, 1985.
71.
SchmidtMJ, SawyerBO, TruexLL, MarshallWS, FleischJH. LY 83583: an agent that lowers intracellular levels of cyclic guanosine 3′5′-monophosphate. J Pharmacol Exp Ther232: 764–769, 1985.
72.
FedeleE, JinY, VarnierG, RaiteriM. In vivo microdialysis study of a specific inhibitors of soluble guanylyl cyclase on the glutamate receptor / nitric oxide / cyclic GMP pathway. British J Pharmacol119: 590–594. 1996.
