Norepinephrine modulates the effect of neuropeptides in coeliac ganglion on ovarian hormones release: Its relationship with ovarian

MARISA HILDA GARRAZA; MYRIAM FORNERIS; LAURA VIRGINIA GATICA; LILIANA BEATRIZ OLIVEROS

NEUROENDOCRINOLOGY LETTERS

MAGHIRA & MAAS PUBLICATIONS

Lugar: SWEDEN; Año: 2010 vol. 31 p. 103 - 112

0172-780X

OBJECTIVE: Ovarian steroids are modulated by neural influences. In this workwe investigate whether norepinephrine (NE) modifies the vasoactive intestinalpeptide (VIP) or neuropeptide Y (NPY) actions in coeliac ganglion (CG) on theovarian hormone release, and evaluate the participation of nitric oxide (NO),measured as nitrite, and of inducible nitric oxide synthetase (iNOS) protein,nerve growth factor (NGF) and its trkA receptor gene expression in the ovarianresponse.METHODS: The study was performed in the ex vivo CG-superior ovarian nerve(SON)-ovary system of rats on diestrus day 2 (D2). CG and ovary were placed inseparate compartments connected by the SON and incubated with Krebs-Ringerbuffer. After addition of 50 ng/ml VIP, 50 ng/ml NPY, 10–6 M NE, or a mix ofVIP+NE or NPY+NE in ganglion, samples from the ovarian compartment weretaken at different times throughout 180 minutes to measure progesterone, androstenedioneand nitrite levels.RESULTS: VIP and NPY in ganglion induced an increase of progesterone releasethat was associated for VIP, but not NPY, with a decrease of ovarian nitrite levels,iNOS protein, and NGF/trkA receptor mRNA expression. By contrast, NE inganglion decreased progesterone, an effect that was suppressed by addition ofpropranolol in ganglion, and increased nitrites/iNOS and NGF/trkA receptorexpression in ovary. GABA A receptor antagonist bicuculline (20 ìM) added inovarian compartment prevented the inhibitory effect on progesterone causedby NE in CG. Androstenedione was not modified under neuropeptides or NEganglionic stimulation.CONCLUSIONS: Finally, results from VIP+NE or NPY+NE in ganglion showedthat ovarian response on D2 induced by VIP or NPY alone is moderated by theopposite action of NE, and occurs only on progesterone, the most sensitive steroidto neural action.