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Titolo:
DOPAMINE-D-2 ACTIONS ON VOLTAGE-DEPENDENT CALCIUM CURRENT AND GONADOTROPIN-II SECRETION IN CULTURED GOLDFISH GONADOTROPHS
Autore:
VANGOOR F; GOLDBERG JI; CHANG JP;
Indirizzi:
UNIV ALBERTA,DEPT BIOL SCI,BIOL SCI BLDG EDMONTON AB T6G 2E9 CANADA UNIV ALBERTA,DEPT BIOL SCI EDMONTON AB T6G 2E9 CANADA
Titolo Testata:
Journal of neuroendocrinology
fascicolo: 3, volume: 10, anno: 1998,
pagine: 175 - 186
SICI:
0953-8194(1998)10:3<175:DAOVCC>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
GROWTH-HORMONE RELEASE; RAT LACTOTROPH CELLS; PROTEIN-KINASE-C; PITUITARY-CELLS; CARASSIUS-AURATUS; SYMPATHETIC NEURONS; POTASSIUM CURRENTS; CA2+ OSCILLATIONS; WHOLE-CELL; GNRH;
Keywords:
DOPAMINE; CALCIUM CURRENT; GONADOTROPHS; GOLDFISH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
48
Recensione:
Indirizzi per estratti:
Citazione:
F. Vangoor et al., "DOPAMINE-D-2 ACTIONS ON VOLTAGE-DEPENDENT CALCIUM CURRENT AND GONADOTROPIN-II SECRETION IN CULTURED GOLDFISH GONADOTROPHS", Journal of neuroendocrinology, 10(3), 1998, pp. 175-186

Abstract

Dopamine D-2-receptor activation directly inhibits GnRH-induced gonadotropin-II (maturational gonadotropin, GTH-II) secretion from goldfishpituitary cells. In this study, we show that dopamine and its D-2 agonist, quinpirole, reduced GTH-II secretion induced by either high extracellular K+ concentration or the voltage-gated Ca2+ channel agonist, Bay K 8644. These actions of dopamine were blocked by addition of the dopamine D-2-receptor antagonist, spiperone. The actions of dopamine on Ca2+ current in single identified goldfish gonadotrophs were assessed in voltage-clamp experiments using Ba2+ as the charge carrier through voltage-gated Ca2+ channels. Dopamine caused a concentration-dependent reduction in Ba2+ current amplitude with an EC50 of 1.0 +/- 0.3 nM,but did not shift the current-voltage relationship. The D-2 agonist quinpirole also caused a dose-dependent reduction in the Ba2+ current amplitude with an EC50 of 2.7 +/- 1.4 nM. Quinpirole slowed the activation and inactivation kinetics, as well as removing the steady-state inactivation properties of the Ba2+ current. In contrast to the actions of quinpirole, the dopamine D-1-receptor agonist, SKF 38393, did not affect the Ba2+ current. The inhibitory action of dopamine on voltage-dependent Ca2+ currents was reversed by spiperone, but not by the D-1 antagonist SKF 83566. Voltage-dependent Na+ and K+ currents were not affected by dopamine or dopamine agonists. These data indicate that dopamine D-2-receptor activation reduces Ca2+ influx through voltage-dependent Ca2+ channels to inhibit GTH-II secretion.

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Documento generato il 18/01/20 alle ore 10:42:23