Neural activity between ovaries and the prevertebral celiac-superior mesenteric ganglia varies during the estrous cycle of the rat

Structural organization of the neuronal pathways of the superior ovarian nerve in the rat

BACKGROUND

In the rat, studies have shown that ovary innervation arrives via the superior ovarian nerve (SON) and the ovarian plexus nerve, which originates from the celiac plexus (CP). In the present study, we performed a neuroanatomical technique to investigate the anatomy of the SON between the ovary and the CP.

RESULTS

We found that the SON fibers were concentrated on the lateral border of the suprarenal ganglion and projected towards, then inserted into the suspensory ligament. Then, it ran parallel to the long axis of the ligament to reach and innervate the ovaries. At this level, the SON was composed of two coiled nerve fibers, each between 10 and 15 µm in diameter. The SON was linked to three different ganglia: the suprarenal ganglia, the celiac ganglia, and the superior mesenteric ganglion.

CONCLUSIONS

The postganglionic fibers that project to the ovary via the SON emerge from the suprarenal ganglia. The trajectories on the right and left sides to each ovary are similar. The somas of ipsilateral and contralateral SON neurons are located in the prevertebral ganglia, mostly in the celiac ganglia.

Superior mesenteric ganglion neural modulation of ovarian angiogenesis, apoptosis and proliferation by the neuroactive steroid allopregnanolone

Allopregnanolone (ALLO), a potent neuroactive steroid, is synthesized and active in the peripheral nervous system. Previous studies have shown that ALLO participates in the central regulation of reproduction with effects on ovarian physiology, although there is little evidence for its ability to modulate peripheral tissues. The present study aimed to determine whether ALLO, administered to an ex vivo system that comprises the superior mesenteric ganglion (SMG), the ovarian nervous plexus (ONP) and the ovary (O), or to the denervated ovary (DO), was able to modify ovarian apoptosis, proliferation and angiogenesis. For this purpose, the SMG-ONP-O system and DO were incubated during 120 min at 37°C, in the presence of two ALLO doses (0.06 µm and 6 µm). The intrinsic and extrinsic pathways of apoptosis were analyzed. Incubation of the SMG-ONP-O system with ALLO 0.06 µm led to an increase in the BAX/BCL-2 ratio and a reduction of FAS-L mRNA levels. ALLO 6 µm induced a decrease of FAS-L levels. Incubation of DO with ALLO 0.06 µm reduced FAS-L, whereas ALLO 6 µm significantly increased it. Cyclin D1 mRNA was measured to evaluate proliferation. Treatment with ALLO 6 µm increased proliferation in both SMG-ONP-O and DO. ALLO 0.06 µm produced an increase of Cyclin D1 in DO only. Administration of either ALLO dose led to a higher ovarian expression of vascular endothelial growth factor in the SMG-ONP-O system, but a lower one in the DO system. ALLO 6 µm induced ovarian sensitization to GABA by increasing GABA_A receptor expression. In conclusion, ALLO participates in the peripheral neural modulation of ovarian physiology. It can also interact directly with the ovarian tissue, modulating key mechanisms involved in normal and pathological processes in a dose-dependent manner.

Administration of a VIP-antagonist in vivo modifies ovarian hormone secretion in a rat model with polycystic ovary syndrome

AIMS

In the cyclic rat in estrus, the vasoactive intestinal peptide (VIP) has an impact on ovarian function, which depends on the endocrine status of the animal. In this work, we aimed to clarify the participation of VIP in the pathophysiological condition of polycystic ovary syndrome (PCOS) using a model of PCOS induced by estradiol valerate (EV-PCOS) in rats.

MAIN METHODS

In the cyclic rat in estrus and in the EV-PCOS model, we analyzed the acute effects of blocking VIP receptors with the use of an antagonist (Ant-VIP) injected into the left or right ovarian bursa on the steroidogenic response and ovarian catecholamine levels.

KEY FINDINGS

In the cyclic animal in estrus, the treatment with Ant-VIP in the left ovarian bursa resulted in a reduction in testosterone serum levels and in ovarian levels of dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC), without changes in 4-hydroxy-3-methoxyphenyl (MHPG) and norepinephrine (NE). When the treatment was applied on the right side, only MHPG levels increased. In the EV-PCOS model, the treatment with Ant-VIP in the left ovarian bursa increased testosterone, estradiol, MHPG, and NE levels. When the treatment was performed on the right side, progesterone levels decreased and estradiol increased, without changes in ovarian catecholamines.

SIGNIFICANCE

The binding of VIP to its receptors differentially regulates steroidogenesis in the cyclic animal in estrus and in the EV-PCOS model. The blocking of VIP signaling produces changes in ovarian catecholamines.

Effect of nervous stimulation on ovarian steroid secretion in amphibians

In the present study, the effect of nerve stimulation on the secretory activity of the ovary of adult females was analyzed for the first time in amphibians. Results revealed that in Rhinella arenarum the stimulation of nerves that supply the gonad induced an increase in estradiol and progesterone secretion, this response showing differences during the reproductive cycle of the species. During the postreproductive period, an increase in estradiol secretion was observed while, in the reproductive period, progesterone secretion increased. Our results suggest that the sympathetic division of the autonomic nervous system would be responsible for this increase, taking into account that, under our experimental conditions, acetylcholine did not affect the endocrine activity of the gonad, while adrenaline (epinephrine) was effective in inducing steroid secretion an effect that could be due to interaction with β receptors. On the other hand, our data show that the association of adrenaline with follicle-stimulating hormone increased estradiol secretion during the postreproductive period, while the association of catecholamine with LH or hCG increased progesterone secretion during the reproductive period. Our results would suggest that nerve stimulation, mediated by the release of adrenaline, would act synergistically with gonadotrophins to stimulate steroid secretion.

"Rapid actions of the neurosteroid allopregnanolone on ovarian and hypothalamic steroidogenesis: Central and peripheral modulation"

The present study aimed to determine whether an i.c.v. administration of allopregnanolone (ALLO) rapidly modifies the hypothalamic and ovarian 3β-hydroxysteroid dehydrogenase (3β-HSD) enzymatic activity and gene expression in in vivo and ex vivo systems in pro-oestrus (PE) and dioestrus I (DI) rats. Animals were injected with vehicle, ALLO, bicuculline or bicuculline plus ALLO and were then killed. In the in vivo experiment, the hypothalamus, ovaries and serum were extracted and analysed. In the ex vivo experiment, the superior mesenteric ganglion - ovarian nerve plexus - ovary system was extracted and incubated during 120 minutes at 37 ºC. The serum and ovarian compartment fluids were used to determine progesterone by radioimmunoanalysis. In the in vivo experiments, ALLO caused a decrease in hypothalamic and ovarian 3β-HSD enzymatic activity during PE. During DI, ALLO increased hypothalamic and ovarian 3β-HSD activity and gene expression. The ovarian 3β-HSD activity increased in both stages in the ex vivo system; gene expression increased only during DI. ALLO induced an increase in serum progesterone only in D1 and in the ovarian incubation liquids in both stages. All findings were reversed by an injection of bicuculline before ALLO. Ovarian steroidogenic changes could be attributed to signals coming from ganglion neurones, which are affected by the acute central neurosteroid stimulation. The i.c.v. administration of ALLO via the GABAergic system altered 3β-HSD activity and gene expression, modulating the neuroendocrine axis. The present study reveals the action that ALLO exerts on the GABAA receptor in both the central and peripheral nervous system and its relationship with hormonal variations. ALLO is involved in the "fine tuning" of neurosecretory functions as a potent modulator of reproductive processes in female rats.

The Neural Signals of the Superior Ovarian Nerve Modulate in an Asymmetric Way the Ovarian Steroidogenic Response to the Vasoactive Intestinal Peptide

The superior ovarian nerve (SON) provides neuropeptide-Y, norepinephrine and vasoactive intestinal peptide (VIP) to the ovaries. Ovarian steroidogenesis is modulated by the SON. In the cyclic rat, the acute steroidogenic response to ovarian microinjection of VIP is asymmetric and varies during the estrous cycle. In the present study, we analyze whether the differential effects of VIP in each ovary are modulated by the neural signals arriving through the SON. Cyclic female rats were submitted on diestrus-1, diestrus-2, proestrus, or estrus to a unilateral section of the SON, and immediately afterward, the denervated ovary was either microinjected or not with VIP. Animals were sacrificed 1 h after treatment. The injection of VIP into the left denervated ovary performed on diestrus-1 decreased progesterone levels in comparison with the left SON sectioning group; similar effects were observed on proestrus when VIP was injected into either of the denervated ovaries. Compared to the left SON sectioning group, VIP treatment into the left denervated ovary on diestrus-2 or proestrus decreased testosterone levels, whereas on diestrus-1, proestrus or estrus, the same treatment resulted in higher estradiol levels. Compared to the right SON sectioning group, VIP injected into the right denervated ovary yielded higher testosterone levels on diestrus-1 and estrus and lower testosterone levels on proestrus. VIP injection into the right denervated ovary increased estradiol levels on diestrus-2 or estrus while decreasing them on proestrus. Our results indicate that in the adult cyclic rat, the set neural signals arriving to the ovaries through the SON asymmetrically modulate the role of VIP on steroid hormone secretion, depending on the endocrine status of the animal. The results also support the hypothesis that the left and right ovary respond differently to the VIPergic stimulus.

Hemi-ovariectomies promote a decrease in the dendritic lengths of CA1 and CA3 neurons: A dimorphic effect of the cerebral hemispheres

Certain structures of the central nervous system (CNS) are morphologically and functionally related to the ovaries. Ovariectomy has been used to study the functional role of the ovaries in the CNS, as well as the role of the CNS on the reproductive system. In the present study, the effects of left and right hemi-ovariectomy on the morphology of pyramidal neurons from the CA1 and CA3 regions of the ventral hippocampus were studied. During the estrus phase, female Long-Evans rats underwent either left and right hemi-ovariectomies or left and right sham surgeries. Three estrous cycles later, the animals were sacrificed, and their brains were processed in Golgi-Cox stain and analyzed by the Sholl method to calculate the dendritic length of the CA1 and CA3 neurons of the left and right hemispheres. The results indicate that the dendritic lengths of the basilar and apical arbors of the CA1 neurons from the left hemisphere were shorter after both left and right hemi-ovariectomy, while the CA1 neurons from the right hemisphere were not affected by either procedure. However, the basilar dendritic arbors of the CA3 neurons from both hemispheres were affected by right hemi-ovariectomy. The spine density only decreased in the apical arbors in the CA3 neurons from the left hemisphere of rats that underwent right hemi-ovariectomy. This study's results indicate that hemi-ovariectomy in adult rats changes in the morphology of the CA1 and CA3 pyramidal neurons in the ventral hippocampus and that there are dimorphic responses between the hemispheres.

Anatomical organization and neural pathways of the ovarian plexus nerve in rats

BACKGROUND

In this work, a detailed anatomical description of the ovarian plexus nerve (OPN) in rats is presented. The distribution of the OPN was analyzed by gross anatomy; the features of the superior mesenteric ganglion (SMG) were determined by histological studies; and the localization of the postganglionic neurons innervating the ovary were identified with retrograde tracer. We studied 19 adult cyclic rats of the CIIZ-V strain.

RESULTS

We found that the right OPN originates from the celiac ganglion, the lumbar ganglion of the sympathetic trunk (LGST) and the SMG. The left OPN originates from the LGST and the anastomotic branch from the splanchnic nerve. The SMG was attached to the inferior vena cava containing sympathetic neurons that innervate the right ovary through the OPN, and which is anatomically single. When the tracer was injected into the right ovary, only the SMG showed positive neurons, while when the tracer was injected into the left ovary, labeled postganglionic neurons were observed in the LGST.

CONCLUSIONS

This is the first time that it is reported that the SMG is attached to the inferior vena cava and it is directly related to the right ovary. The neural pathways and sympathetic ganglia involved in the communication between the ovaries and the preganglionic neurons are different in the left and right side.

Oxidative stress and altered steroidogenesis in the ovary by cholinergic stimulation of coeliac ganglion in the first proestrous in rats. Implication of nitric oxide

An ex-vivo Coeliac Ganglion-Superior Ovarian Nerve-Ovary (CG-SON-O) system from virgin rats in the first proestrous was used to test whether cholinergic stimulation of CG affects oxidative status and steroidogenesis in the ovary. The CG and the O were placed in separate buffered-compartments, connected by the SON, and the CG was stimulated by acetylcholine (Ach). To test a possible role of nitric oxide (NO) in the ovarian response to cholinergic stimulation of CG, aminoguanidine (AG) - an inhibitor of inducible-NO synthase was added to the O compartment. After 180 min incubation, the oxidative status was assessed in O whereas nitrite and steroidogenesis were assessed at 30, 120 and 180 min. Ach in CG decreased the total antioxidant capacity, but increased NO production and protein carbonization in O. Ach stimulation of CG increased estradiol, but decreased progesterone release in O by reducing the mRNAs related to their synthesis and degradation. The addition of AG to the O compartment caused an opposite effect, which was more pronounced in the presence of Ach in the CG compartment than in its absence. These results show that the stimulation of the extrinsic-cholinergic innervation of the O increases the concentration of NO, causes oxidative stress and modulates steroidogenesis in the first rat proestrous.

Effects of ovarian dopaminergic receptors on ovulation

Hormonal and neural signals regulate the ovarian follicular development. The present study's hypothesis is that the blockade of ovarian dopamine receptors locally will affect follicle development and ovulation. Groups of adult 4-day cyclic rats of the CII-ZV strain on estrus, diestrus-1, diestrus-2, or proestrus day were injected with vehicle, haloperidol (DA2 > DA1 blocker), sulpiride (DA2 blocker), or SCH-23390 (DA1 blocker) into the bursa of both ovaries at 08:00, 13:00, or 20:00 h. Animals were sacrificed the following predicted estrus day. The following treatments blocked ovulation: injecting haloperidol to rats on estrus or diestrus-1 at 8:00, 13:00, or 20:00 h and to rats on diestrus-2 at 08:00, or 20:00 h; injecting SCH-23390 to rats on diestrus-1 at 8:00, 13:00, or 20:00 h; injecting sulpiride to rats on estrus at 20:00 h, diestrus-1 at 08:00, 13:00, or 20:00 h and to rats on diestrus-2 at 08:00 h. In rats treated with any of the dopamine antagonists that blocked ovulation, injecting GnRH at 14.00 h on the next predicted proestrus day restored ovulation. Injecting estradiol benzoate at 14.00 h of the next predicted diestrus-2 restored ovulation in some animals treated with haloperidol on estrus or diestrus-2 and was ineffective in rats treated on diestrus-1. In rats treated with sulpiride or SCH-23390 ovulation occurred in most animals (SCH-23390: 6/8; SPD: 9/12). Present results suggest that dopamine ovarian receptors' participation in regulating follicular development and ovulation varies along the estrus cycle, with their most prominent activity occurring on diestrus-1.

Ovulation requires the activation on proestrus of M₁ muscarinic receptors in the left ovary

We analyzed the effects of chemically blocking type 1 muscarinic receptors (M1R) on either the left or right ovary on ovulation rate, number of ova shed and steroid hormones levels. M1R were unilaterally blocked in ovary with the M1R selective antagonist pirenzepine (PZP). PZP was delivered into the bursa ovarica of the left or right ovary of adult rats at 13:00 h on proestrus day. PZP treatment in the left but not in the right ovary blocked ovulation. PZP did not modify the number of ova shed, nor progesterone or 17β-estradiol serum levels. The surge of luteinizing hormone levels was diminished while that of follicle-stimulating hormone did not change in animals treated with PZP in the left ovary. Interestingly, treatment with either synthetic luteinizing hormone-releasing hormone or human chorionic gonadotropin 1 h after PZP administration in the left ovary restored ovulation in both ovaries. The presence of M1R protein in the theca cells of the ovarian follicles as well as in cells of the corpus luteum was detected on proestrus day. These results suggest that M1R activation in the left ovary is required for pre-ovulatory gonadotropin-releasing hormone (GnRH) secretion and ovulation. Furthermore, these results also suggest that M1R in the left ovary might be regulating ovulation asymmetrically through a stimulatory neural signal relayed to the hypothalamus via the vagus nerve to induce the GnRH secretion which then triggers ovulation.

Asymmetric steroidogenic response by the ovaries to the vasoactive intestinal peptide

In vitro the vasoactive intestinal peptide (VIP) stimulates progesterone, androgens, and estradiol secretion, and the effects are time-dependent. The present study analyzed the acute (1 h) and sub-acute (24 h) effects of unilateral injection of VIP into the ovarian bursa on each day of the estrous cycle on progesterone, testosterone, and estradiol serum levels. Cyclic 60-day-old virgin female rats on diestrus-1, diestrus-2, proestrus, or estrus were injected with saline or VIP 10(-6) M into the left or right ovarian bursa. One hour after saline injection on each day of estrus cycle, progesterone levels were higher than in control animals. The acute effects of saline solution on testosterone and estradiol levels were asymmetric and varied during the estrous cycle. In comparison with saline groups, the effects of VIPergic stimulation on progesterone, testosterone, and estradiol serum levels depend on the time elapsed between treatment and autopsy and vary during the estrous cycle. An acute asymmetric response from the ovaries to the VIP was observed at diestrus-1, diestrus-2, and proestrus on progesterone and estradiol levels. The asymmetries on testosterone levels were observed at diestrus-1, diestrus-2, and estrus days. The present results suggest that in the cyclic rat, each ovary has different sensitivities to VIPergic stimulation which depends on the endocrine status of the animal.

Unilateral or bilateral vagotomy induces ovulation in both ovaries of rats with polycystic ovarian syndrome

BACKGROUND

Injecting estradiol valerate (EV) to pre-pubertal or adult female rat results in effects similar to those observed in women with polycystic ovarian syndrome (PCOS). One of the mechanisms involved in PCOS development is the hyperactivity of the sympathetic nervous system. In EV-induced PCOS rats, the unilateral sectioning of the superior ovarian nerve (SON) restores ovulation of the innervated ovary. This suggests that, in addition to the sympathetic innervation, other neural mechanisms are involved in the development/maintenance of PCOS. The aims of present study were analyze if the vagus nerve is one of the neural pathways participating in PCOS development.

METHODS

Ten-day old rats were injected with EV dissolved in corn oil. At 24-days of age sham-surgery, unilateral, or bilateral sectioning of the vagus nerve (vagotomy) was performed on these rats. The animals were sacrificed at 90-92 days of age, when they presented vaginal estrous preceded by a pro-estrus smear.

RESULTS

In EV-induced PCOS rats, unilateral or bilateral vagotomy restored ovulation in both ovaries. Follicle-stimulating hormone (FSH) levels in PCOS rats with unilateral or bilateral vagotomy were lower than in control rats.

CONCLUSIONS

This result suggests that in EV-induced PCOS rats the vagus nerve is a neural pathway participating in maintaining PCOS. The vagus nerve innervates the ovaries directly and indirectly through its synapsis in the celiac-superior-mesenteric ganglion, where the somas of neurons originating in the SON are located. Then, it is possible that vagotomy effects in EV-induced PCOS rats may be explained as a lack of communication between the central nervous system and the ovaries.

Identification of a novel lipin homologue from the parasitic protozoan Trypanosoma brucei

Background

Arginine methylation is a post-translational modification that expands the functional diversity of proteins. Kinetoplastid parasites contain a relatively large group of protein arginine methyltransferases (PRMTs) compared to other single celled eukaryotes. Several T. brucei proteins have been shown to serve as TbPRMT substrates in vitro, and a great number of proteins likely to undergo methylation are predicted by the T. brucei genome. This indicates that a large number of proteins whose functions are modulated by arginine methylation await discovery in trypanosomes. Here, we employed a yeast two-hybrid screen using as bait the major T. brucei type I PRMT, TbPRMT1, to identify potential substrates of this enzyme.

Results

We identified a protein containing N-LIP and C-LIP domains that we term TbLpn. These domains are usually present in a family of proteins known as lipins, and involved in phospholipid biosynthesis and gene regulation. Far western and co-immunoprecipitation assays confirmed the TbPRMT1-TbLpn interaction. We also demonstrated that TbLpn is localized mainly to the cytosol, and is methylated in vivo. In addition, we showed that, similar to mammalian and yeast proteins with N-LIP and C-LIP domains, recombinant TbLpn exhibits phosphatidic acid phosphatase activity, and that two conserved aspartic acid residues present in the C-LIP domain are critical for its enzymatic activity.

Conclusions

This study reports the characterization of a novel trypanosome protein and provides insight into its enzymatic activity and function in phospholipid biosynthesis. It also indicates that TbLpn functions may be modulated by arginine methylation.

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.

Epigenetic factors and cardiac development

Congenital heart malformations remain the leading cause of death related to birth defects. Recent advances in developmental and regenerative cardiology have shed light on a mechanistic understanding of heart development that is controlled by a transcriptional network of genetic and epigenetic factors. This article reviews the roles of chromatin remodelling factors important for cardiac development with the current knowledge of cardiac morphogenesis, regeneration, and direct cardiac differentiation. In the last 5 years, critical roles of epigenetic factors have been revealed in the cardiac research field.

Effects of acute unilateral ovariectomy to pre-pubertal rats on steroid hormones secretion and compensatory ovarian responses

In the present study we analyzed the existence of asymmetry in the secretion of steroid hormones in pre-pubertal female rats treated with unilateral ovariectomy (ULO) or unilateral perforation of the abdominal wall (sham-surgery). Treated rats were sacrificed at different times after surgery. Since sham-surgery had an apparent effect on the age of first vaginal estrous (FVE) and serum levels hormone, the results of the sham surgery groups were used to assess the effects of their respective surgery treatment groups. On the day of FVE, compensatory ovulation (CO) and compensatory ovarian hypertrophy (COH) were similar in animals with ULO, regardless of the ovary remaining in situ. In ULO treated animals, progesterone (P4) levels were higher than in animals with sham-surgery one hour after treatment but lower in rats sacrificed at FEV. Left-ULO resulted in lower testosterone (T) concentration 48 and 72 hours after surgery. In rats with Right-ULO lower T concentrations were observed in rats sacrificed one or 72 hours after surgery, and at FVE. ULO (left or right) resulted in lower estradiol (E2) concentrations one or 72 hours after treatment. In rats with Left-ULO, E2 levels were higher 48 hours after surgery and at FVE. Left-ULO resulted in higher levels of follicle stimulating hormone (FSH) five hours after surgery and at FVE. FSH levels were higher in rats with Right-ULO sacrificed on FVE. The present results suggest that in the pre-pubertal rat both ovaries have similar capacities to secrete P4, and that the right ovary has a higher capacity to secrete E2. Taken together, the present results support the idea that the effects of ULO result from the decrease in glandular tissue and changes in the neural information arising from the ovary.

Acute effects of unilateral sectioning the superior ovarian nerve of rats with unilateral ovariectomy on ovarian hormones (progesterone, testosterone and estradiol) levels vary during the estrous cycle

The present study analyzed the participation of the left and right superior ovarian nerves (SON) in regulating progesterone, testosterone, and estradiol serum levels in unilaterally ovariectomized rats on each day of the estrous cycle. For this purpose, ovarian hormone concentrations in serum were measured in animals with either sham-surgery, unilateral ovariectomy (ULO), unilateral sectioning of the SON, or sectioning of the SON innervation of the in situ ovary in rats with ULO.This investigation results show that the right and left ovaries have different capacities to maintain normal hormone levels, that such capacity varies during the estrous cycle, and that it depends on the integrity of the SON innervation. In rats with only one ovary, the effects of ovarian denervation on hormone levels varied according to which ovary remained in situ, the specific hormone, and the day of the estrous cycle when treatment was performed. Present results support the idea that the ovaries send and receive neural information that is processed in the central nervous system and we propose that this information participates in controlling the secretion of gonadotropins related to the regulation of ovarian functions.

Endometriosis-induced vaginal hyperalgesia in the rat: role of the ectopic growths and their innervation

Endometriosis is a painful disorder defined by extrauteral endometrial growths whose contribution to pain symptoms is poorly understood. Endometriosis is created in rats by autotransplanting on abdominal arteries pieces of either uterus (ENDO), which form cysts, or fat (shamENDO), which do not form cysts. ENDO, but not shamENDO induces vaginal hyperalgesia. We tested the hypothesis that the cysts are necessary to maintain vaginal hyperalgesia by assessing the effect of surgically removing them. Complete-cyst-removal eliminated ENDO-induced vaginal hyperalgesia up to 4 months post-operatively. Sham-cyst-removal in ENDO rats, in which cysts were not removed, or partial cyst-removal increased the ENDO-induced hyperalgesia. The decreases and increases both took 3-6 weeks to develop. Changes in ENDO-induced hyperalgesia did not occur in a control group of ENDO rats who had no surgery after ENDO. In a double-surgery control group, neither shamENDO surgery nor a subsequent sham surgery that mimicked "removal" of non-existent cysts influenced vaginal nociception. In a no-surgery control group, vaginal nociception remained stable for >6 months. The increases in ENDO-induced hyperalgesia produced by the sham-cyst-removal surgery were smaller in proestrus than in other estrous stages. During the other stages (but not during proestrus), sympathetic innervation of the cysts increased. These results suggest that maintenance of ENDO-induced vaginal hyperalgesia requires continued presence of at least some ectopic endometrial tissue, and that surgical treatment that fails to remove ectopic endometrial tissue can exacerbate the hyperalgesia, possibly due in part to an increase in the cysts' sympathetic innervation.

Lateralization of the connections of the ovary to the celiac ganglia in juvenile rats

During the development of the female rat, a maturing process of the factors that regulate the functioning of the ovaries takes place, resulting in different responses according to the age of the animal. Studies show that peripheral innervation is one relevant factor involved.In the present study we analyzed the anatomical relationship between the neurons in the celiac-superior mesenteric ganglia (CSMG), and the right or left ovary in 24 or 28 days old female pre-pubertal rats. The participation of the superior ovarian nerve (SON) in the communication between the CSMG and the ovaries was analyzed in animals with unilateral section of the SON, previous to injecting true blue (TB) into the ovarian bursa. The animals were killed seven days after treatment. TB stained neurons were quantified at the superior mesenteric-celiac ganglia.The number of labeled neurons in the CSMG of rats treated at 28 days of age was significantly higher than those treated on day 24. At age 24 days, injecting TB into the right ovary resulted in neuron stains on both sides of the celiac ganglia; whereas, injecting the left side the stains were exclusively ipsilateral. Such asymmetry was not observed when the rats were treated at age of 28 days.In younger rats, sectioning the left SON resulted in significantly lower number of stained neurons in the left ganglia while sectioning the right SON did not modify the number of stained neurons. When sectioning of the SON was performed to 28 days old rats, no staining was observed.Present results show that the number and connectivity of post-ganglionic neurons of the CSMG connected to the ovary of juvenile female rats change as the animal mature; that the SON plays a role in this communication process as puberty approaches; and that this maturing process is different for the right or the left ovary.

Asymmetric post-natal development of superior cervical ganglion of paca (Agouti paca)

Functional asymmetry has been reported in sympathetic ganglia. Although there are few studies reporting on body side-related morphoquantitative changes in sympathetic ganglion neurons, none of them have used design-based stereological methods to address this issue during post-natal development. We therefore aimed at detecting possible asymmetry-related effects on the quantitative structure of the superior cervical ganglion (SCG) from pacas during ageing, using very precise design-based stereological methods. Forty (twenty left and twenty right) SCG from twenty male pacas were studied at four different ages, i.e. newborn, young, adult and aged animals. By using design-based stereological methods the total volume of ganglion and the total number of mononucleate and binucleate neurons were estimated. Furthermore, the mean perikaryal volume of mononucleate and binucleate neurons was estimated, using the vertical nucleator. The main findings of this study were: (1) the right SCG from aged pacas has more mononucleate and binucleate neurons than the left SCG in all other combinations of body side and animal age, showing the effect of the interaction between asymmetry (right side) and animal age, and (2) right SCG neurons (mono and binucleate) are bigger than the left SCG neurons (mono and binucleate), irrespective of the animal age. This shows, therefore, the exclusive effect of asymmetry (right side). At the time of writing there is still no conclusive explanation for some SCG quantitative changes exclusively assigned to asymmetry (right side) and those assigned to the interaction between asymmetry (right side) and senescence in pacas. We therefore suggest that forthcoming studies should focus on the functional consequences of SCG structural asymmetry during post-natal development. Another interesting investigation would be to examine the interaction between ganglia and their innervation targets using anterograde and retrograde neurotracers. Would differences in the size of target organs explain ganglia structural asymmetry?

Predominance of supraspinal innervation of the left ovary

In our previous studies using the viral transneuronal tracing technique we demonstrated the spinal and supraspinal components of the ovarian innervation. Since increasing number of data indicate the presence of morphological and functional laterality in the control of gonadal functions, we aimed to investigate whether cerebral structures trans-synaptically involved in the innervation of the ovary exhibit asymmetry or not. In one of the studies the left or the right ovary was injected with the red fluorescent protein expressing pseudorabies virus and the number of infected "red" autofluorescent neurons from the right and the left ovary was compared. In another study in order to have distinct labeling of cell groups connected with the right- and left-sided ovary in the same animal, a dual viral labeling was applied. The left- and right-sided ovary were inoculated with genetically engineered pseudorabies virus expressing a red fluorescent protein or a green fluorescent protein gene. Viral infection of brain nuclei including the dorsal vagal nucleus, caudal raphe nuclei, A5 noradrenergic cell group, hypothalamic paraventricular nucleus, from the left ovary in each case was enhanced when compared with labeling from the right gonad. Data suggest a predominance in the supraspinal innervation of the left ovary.

Ipsilateral vagotomy to unilaterally ovariectomized pre-pubertal rats modifies compensatory ovarian responses

The present study evaluates the participation of the vagus nerve in pre-pubertal rats with unilateral ovariectomy on puberty onset, and on progesterone, testosterone and estradiol serum levels, and the compensatory responses of the ovary. Unilateral vagotomy did not modify the onset of puberty in unilaterally ovariectomized rats. Ovulation rates of animals with the left vagus nerve sectioned and the left ovary in-situ was lower than in rats with only unilateral ovariectomy. Sectioning the left vagus to 32-day old rats with the left ovary in-situ resulted in lower compensatory ovarian hypertrophy than in rats with right unilateral ovariectomy. Twenty-eight or 32-day old animals with sectioning of the right vagus nerve and the right ovary in situ showed higher compensatory ovulation. Twenty-eight -day old rats with the right ovary in situ had higher progesterone and testosterone levels than animals of the same age with the left ovary in-situ. Compared to animals with the right ovary in situ, animals treated at 32-days of age, sectioning the ipsi-lateral vagus nerve resulted in higher progesterone levels. Higher progesterone levels were observed in 28- and 32 days old rats with the left ovary in situ and left vagus nerve sectioned. Thirty-two day old animals with the right ovary in situ and right vagus nerve sectioned had higher progesterone levels than rats of the same age with the left ovary in situ and left vagus nerve sectioned. Left vagotomy to 28-day old rats with the left ovary in situ resulted in higher testosterone levels, a reverse response to that observed in animals with sectioning of the right vagus and the right ovary in situ. Thirty-two day old rats with the left ovary in situ and left vagus nerve sectioned showed lower testosterone levels than animals without vagotomy and with the left ovary in situ.Twenty-eight -day old animals with the left vagus sectioned and left ovary in situ had lower estradiol serum levels than rats without unilateral vagotomy, a response similar to that observed in 32-day old rats with the right ovary in situ and right vagus nerve sectioned. Present results suggest an asymmetric regulation of steroid hormones secretion by the vagus nerve innervations in animals with unilateral ovariectomy, and those differences in testosterone serum levels observed are associated to the ovary remaining in-situ, vagal innervation and age when the animals were treated.

Increased Protein Arginine Methylation in Chronic Hypoxia

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthesis. ADMA is generated by catabolism of proteins containing methylated arginine residues, and its levels are correlated with endothelial dysfunction in systemic cardiovascular diseases. Arginine methylation of cellular proteins is catalyzed by protein arginine methyltransferases (PRMT). The expression and localization of PRMT in the lung has not been addressed. Here, we sought to analyze the expression of PRMT isoforms in the lung and to determine whether PRMT expression is altered during exposure to chronic hypoxia (10% oxygen). Adult mice were exposed to hypoxia for up to 3 wk, and lung tissues were harvested and processed for RT-PCR, Western blotting, immunohistochemistry, and determination of tissue ADMA levels. All PRMT isoforms investigated were detected at the mRNA and protein level in mouse lung, and were localized primarily to the bronchial and alveolar epithelium. In lungs of mice subjected to chronic hypoxia, PRMT2 mRNA and protein levels were up-regulated, whereas the expression of all other PRMT isoforms remained unchanged. This was mainly due to increased expression of PRMT2 in alveolar type II cells, which did not express detectable levels of PRMT2 under normoxic conditions. Consistent with these observations, lung ADMA levels and ADMA/l-Arginine ratios were increased under hypoxic conditions. These results demonstrate that PRMTs are expressed and functional in the lung, and that hypoxia is a potent regulator of PRMT2 expression and lung ADMA concentrations. These data suggest that structural and functional changes caused by hypoxia may be linked to ADMA metabolism.

The participation of the cholinergic system in regulating progesterone secretion through the ovarian-adrenal crosstalk varies along the estrous cycle

This study was designed to analyze the acute effects of unilateral or bilateral ovariectomy or adrenalectomy, performed on different days of the estrous cycle, on progesterone (P4) serum levels 1 h after surgery. The effects of blocking the cholinergic system by injecting atropine sulfate were also analyzed. Ether anesthesia treatment on diestrus 1 (D1) increased P4 serum levels. Compared to right sham-operated animals, right ovariectomy (left ovary in situ) performed on diestrus 2 (D2) or proestrus (P), resulted in P4 serum levels increase. Compared to animals with left sham surgery, left adrenalectomy (right adrenal in situ) performed on P day resulted in significantly lower P4 concentrations. Bilateral adrenalectomy resulted in a significant drop of P4 serum levels; the most remarkable drop was observed in animals treated on D2. Bilateral ovariectomy performed on D1 resulted in lower P4 serum levels, and the same treatment performed on P resulted in a significant rise of P4 serum levels. Injecting atropine sulfate to untouched (control group) rats resulted in significantly higher P4 concentrations. Blocking the cholinergic sys-tem on D1 or P to rats with the right adrenal removed resulted in lower P4 serum levels; while, in contrast, atropine sulfate treatment performed on D2 resulted in P4 serum levels increase. The results support the hypothesis of asymmetry in the ovaries' and adrenals' capacities to secrete P4; that this capacity varies along the estrous cycle; and that P4 secretion by the ovaries and adrenals is regulated by the cholinergic system.