Involvement of the mesenteric ganglia on androstenedione, noradrenaline and nitrite release using a testis ex vivo system.

The autonomic nerve fibres converge to the testis along two major pathways, the superior spermatic nerve (SSN) and the inferior spermatic nerve (ISN). The object of this work was to evaluate whether the addition of noradrenaline (NA) in the ganglionic compartment of two ex vivo systems: superior mesenteric ganglion (SMG)-SSN-testis, inferior mesenteric ganglion (IMG)-ISN-testis modulate androstenedione (A2), NA and nitrite release and to determine whether there are secretory differences between the right and the left testis. Each gonad with its respective ganglion was transferred into a cuvette with two compartments and incubated in a Dubnoff metabolic shaker. The testis incubation liquids were collected and analysed for NA by HPLC, A2 by RIA and nitrites by the Griess method. When NA is added to the IMG, A2 and NA release diminishes and nitrite increases in the left testis, while in the right gonad, A2 and NA increase and nitrite decreases. When NA was administered to the SMG, A2 and NA increase and nitrite diminishes in the left gonad, but they show opposite fluctuations in the right testis. These ex vivo systems appear to be excellent models for studying the sympathetic ganglionic control of the testis though A2, NA and nitrite release from the male gonad. It is evident that a better knowledge about the role of catecholamines and nitric oxide in the testis physiology may facilitate the understanding of some reproductive diseases.

Coeliac ganglion adrenergic activity modifies ovarian progesterone during pregnancy: its inter-relationship with LH.

Most of the fibres that constitute the superior ovarian nerve (SON) originate at the neuronal bodies of the coeliac ganglion and innervate rat ovarian stroma cells. The purpose of this work was to study the part played by innervation on ovarian release of progesterone on day 15 and at the end of pregnancy in an integrated in vitro system known as the coeliac ganglion-SON-ovary system. We also investigated, in the same system, whether there is some kind of inter-relationship between the effect of adrenergic agents and LH on progesterone release on day 15 of pregnancy. The coeliac ganglion and the ovary were incubated in separate compartments, linked by the SON. The ovary was immersed in 2 ml buffer solution (ovarian compartment) and the coeliac ganglion was immersed in 2 ml of a different buffer solution (ganglion compartment). Under these conditions, the accumulation of progesterone in the ovarian compartment medium was used as an endpoint. Conditions were standardised on day 15 of pregnancy, when the decrease in the release of ovarian progesterone caused by non-specific stimulation on the ganglion with KCl (56 mM) demonstrated the functional integrity of the system. Neural influence was evaluated by the addition of adrenergic agents at a concentration of 10(-6)M to the coeliac ganglion. On day 15 of pregnancy, noradrenaline and propranolol increased progesterone release while phentolamine diminished it. The existence of ganglionic tone was assessed by analysing progesterone basal levels at different stages of pregnancy. The highest secretion of progesterone was found to take place on day 15, diminishing as pregnancy advanced. In addition, adrenergic neural participation was studied during the physiological luteolysis occurring at the end of pregnancy. Major findings were that noradrenaline increased ovarian accumulation of progesterone on day 19 and decreased it on day 20, while propranolol and phentolamine diminished progesterone release on both days. In additional studies, some neuroendocrine aspects were investigated at a peripheral level. The addition of LH only to the ovarian compartment did not affect progesterone secretion. However, when LH in the ovarian compartment was accompanied by noradrenaline, propranolol or phentolamine in the ganglion compartment, the release of progesterone decreased. It can be concluded that modifications of the neural state of the coeliac ganglion affect ovarian progesterone secretion and the physiology of pregnancy via the SON. The results may confirm that the coeliac ganglion-SON-ovary system provides a direct link between the autonomic nervous system and physiological events during pregnancy.

Adrenergic influences on coeliac ganglion affect the release of progesterone from cycling ovaries: characterisation of an in vitro system.

The superior ovarian nerve (SON) arrives at the ovary through the suspensory ligament and innervates mainly the ovarian stroma. Most neurones from which the SON fibres originate are located in the complex coeliac and mesenteric ganglia. Taking into account that other ganglia have been shown to have alpha- and beta-adrenergic receptors, and that the coeliac ganglion receives adrenergic fibres from other sympathetic paravertebral and preaortic ganglia, we utilised adrenergic agonists and antagonists specific to the ganglion, to analyse the role of the alpha and beta receptors in ovarian physiology. To that end, it was necessary to develop and standardise an in vitro coeliac ganglion-SON-ovary (coeliac ganglion-SON-O) experimental system that would enable study of the release of steroids in the ovary in the absence of humoral factors. We investigated the effect of adrenergic agents on the liberation of progesterone in the different stages of the oestrous cycle. To this end we placed the coeliac ganglion and the ovary in different compartments, connected through the SON, to produce a system being studied as a whole. Combined neural and hormonal (luteinising hormone (LH)) effects were also examined. Non-specific stimulation with KCl in the ganglion compartment evoked different responses in terms of release of progesterone, depending on the physiological conditions of the cycle; this demonstrated the sensitivity and viability of the system. During pro-oestrus, stimulation of the ganglion compartment with adrenergic agents such as the agonist noradrenaline or the beta-adrenergic antagonist propranolol, did not modify the release of progesterone. In contrast, the alpha-adrenergic antagonist, phentolamine, induced a strong inhibitory response. During the oestrous stage, noradrenaline was inactive, but phentolamine and propranolol exerted a strong stimulus throughout the experiment. On dioestrus day 1 (D1), both noradrenaline and propranolol increased the release of ovarian progesterone, whereas phentolamine had the opposite effect. Finally, on dioestrus day 2 (D2), what was noteworthy was the pronounced inhibitory effect of noradrenaline, whereas phentolamine was inactive and propranolol showed its greatest stimulatory effect. In order to compare the combined neural and endocrine effects on the ovarian release of progesterone, the experiment was carried out during stages D1 and D2, when the corpora lutea are at their peak of activity. Adrenergic agents were added to the ganglion and LH in a final concentration of 50 ng/ml was added to the ovarian comparment. Different effects were observed indicating a differential response to these agents in stimulated and basal conditions. We conclude that the in vitro coeliac ganglion-SON-ovary system is a functional entity because it possesses its own autonomic tone. This is verified because different basal values of progesterone appear in the different stages of the oestrous cycle. In similar fashion, variations of progesterone induced via the neural pathway were observed under different experimental conditions. In contrast, on D2, noradrenaline added to the ganglion compartment had an inhibitory effect on the liberation of ovarian progesterone. This would indicate that, during this phase, noradrenaline may not be the neurotransmitter released in the ovarian compartment, but that other inhibitory molecules might participate in the observed effects. Finally, during D2, the neural input would condition the ovarian response to LH, facilitating the decrease in progesterone necessary to start a new cycle. The experimental scheme is, in our opinion, a valuable tool for the study of peripheral neural participation in ovarian physiology.