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Titolo:
Melatonin synthesis in the greenfrog retina in culture: II. Dopaminergic and adrenergic control
Autore:
Alonso-Gomez, AL; Valenciano, AI; Alonso-Bedate, M; Delgado, MJ;
Indirizzi:
Univ Complutense, Fac Biol, Dpto Biol Anim 2, E-28040 Madrid, Spain Univ Complutense Madrid Spain E-28040 Biol Anim 2, E-28040 Madrid, Spain
Titolo Testata:
LIFE SCIENCES
fascicolo: 8, volume: 66, anno: 2000,
pagine: 687 - 695
SICI:
0024-3205(20000114)66:8<687:MSITGR>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
SEROTONIN N-ACETYLTRANSFERASE; PIGMENT EPITHELIUM; ADENYLATE-CYCLASE; CELL-CULTURES; CHICK RETINA; FROG RETINA; RECEPTORS; PINEAL; LIGHT; BIOSYNTHESIS;
Keywords:
melatonin; retina; frog; in vitro; NAT activity; dopaminergic receptors; adrenergic receptors; retinal photoreceptors;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Alonso-Gomez, AL Univ Complutense, Fac Biol, Dept Biol Anim 2, Madrid 2840, Spain Univ Complutense Madrid Spain 2840 , Madrid 2840, Spain
Citazione:
A.L. Alonso-Gomez et al., "Melatonin synthesis in the greenfrog retina in culture: II. Dopaminergic and adrenergic control", LIFE SCI, 66(8), 2000, pp. 687-695

Abstract

Serotonin N-acetyltransferase (NAT) activity and melatonin show a daily rhythm with high levels at night. Although the rhythmic properties of NAT andmelatonin are similar in pineal gland and retina, great differences in thelight perception and transmission mechanisms exist. We have analyzed the effects of adrenergic and dopaminergic agents on greenfrog (Rana perezi) eyecup culture, in order to identify the receptors involved in the regulation of retinal melatonin synthesis. A D-2-like receptor is directly involved inthe regulation of NAT activity and melatonin release in R. perezi retina. Quinpirole mimics the effect of light, reducing the darkness-stimulated NATactivity and melatonin release, while sulpiride antagonized these actions. Neither D-1-agonist (SKF 38393) nor D-1-antagonist (SCH 23390) had effect on NAT activity. However, a significant inhibition of darkness-evoked melatonin release was produced by SKF 38393 after 6 hours of culture. The beta- and alpha(1)-agonists showed a clear inhibition. However, a direct effect of beta, alpha(1) and D-1-agonists on photoreceptors is unproven, being moreprobable that the adrenergic actions imply a non-photoreceptor retinal cell. In conclusion, eyecup culture of Rana perezi revealed a dopaminergic control of melatonin synthesis and a possible modulation of dopaminergic tone by adrenergic receptors. Melatonin release is a more sensitive parameter than NAT activity to the action of neuroactive agents, suggesting that melatonin synthesis can be regulated by more than one enzymatic step in Rana perezi.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 00:10:44