Ovaric physiology in the first oestral cycle: influence of noradrenergic and cholinergic neural stimuli from coeliac ganglion.

Both peripheral innervation and nitric oxide (NO) participate in ovarian steroidogenesis. The aims of the work were (1) to investigate whether ganglionic noradrenergic (NE) and cholinergic (Ach) stimulus modify the ovarian steroids and NO release and (2) to examine the effect of those stimuli on the mRNA expression of 3beta-HSD and P450 aromatase in the ovary. The experiments were carried out using the ex vivo coeliac ganglion-superior ovarian nerve-ovary (CG-SON-O) system of rats in the first oestral cycle. The system was incubated in a buffer solution for 120min, with the ganglion and ovary located in different compartments and linked by the SON. NE and Ach were added into the ganglion compartment. Both NE and Ach predominantly induced ovarian release of androstenedione and oestradiol while inhibited progesterone release. Ovarian NO release increased after ganglionic stimulation during proestrous while its secretion decreased during the diestrous. Noteworthily, 3beta-HSD and P450 aromatase expression were modulated by neural stimulation. In the follicular phase, Ach in CG increased 3beta-HSD and NE increased P450 aromatase. In the luteal phase both neurotransmitters increased 3beta-HSD and Ach increased P450 aromatase transcript levels. All above observations suggest that the preponderancy of an either noradrenergic or cholinergic effect would depend on the stage of the first oestral cycle in the rat. The ovarian response to noradrenergic and cholinergic stimuli on GC, via SON, is strongly linked to oestral-stage-specific ovarian structures and their secretion products.