ABSTRACT
The development of dressings based on electrospun membranes with polymers and plant extracts is an interesting approach to skin regeneration, providing elements to prevent contamination and a matrix that accelerates the healing process. We developed a membrane composed of polyvinylpyrrolidone (PVP), gel and Aloe vera peel extract via the electrospinning technique. Additionally, an optimal ratio of PVP/Av gel/Av skin extract was determined to facilitate membrane formation. Electrospun membranes were obtained with fiber diameters of 1403 ± 57.4 nm for the PVP and 189.2 ± 11.4 nm for PVP/Av gel/Av peel extract, confirming that the use of extracts generally reduced the fiber diameter. The incorporation of gel and peel extract of Aloe vera into the electrospun membrane was analyzed via FTIR and UV-Vis spectroscopies. FTIR revealed the presence of functional groups associated with phenolic compounds such as aloin, aloe-emodin, emodin and aloesin, which was confirmed by UV-Vis, revealing absorption bands corresponding to aloin, phenols and carbonyl groups. This finding provides evidence of the effective integration and prevalence of bioactive compounds of a phenolic and polysaccharide nature from the gel and the Av skin extract in the electrospun fibers, resulting in an advanced membrane that could improve and accelerate the healing process and protect the wound from bacterial infections.
ABSTRACT
Autism Spectrum Disorder (ASD) is characterized by differences in social communication and interaction, as well as areas of focused interests and/or repetitive behaviors. Recent studies have highlighted a higher prevalence of endocrine and reproductive disturbances among females on the autism spectrum, hinting at potential disruptions within the hypothalamus-pituitary-ovary (HPO) axis. This research aims to explore the reproductive health disparities in ASD using an animal model of autism, the C58/J inbred mouse strain, with a focus on reproductive performance and hormonal profiles compared to the C57BL/6J control strain. Our findings revealed that the estrous cycle in C58/J females is disrupted, as evidenced by a lower frequency of complete cycles and a lack of cyclical release of estradiol and progesterone compared to control mice. C58/J females also exhibited poor performance in several reproductive parameters, including reproductive lifespan and fertility index. Furthermore, estrogen receptor alpha content showed a marked decrease in the hypothalamus of C58/J mice. These alterations in the estrous cycle, hormonal imbalances, and reduced reproductive function imply dysregulation in the HPO axis. Additionally, our in-silico study identified a group of genes involved in infertility carrying single-nucleotide polymorphisms (SNPs) in the C58/J strain, which also have human orthologs associated with autism. These findings could offer valuable insights into the molecular underpinnings of neuroendocrine axis disruption and reproductive issues observed in ASD.
ABSTRACT
The neuropeptide kisspeptin (Kiss) is crucial in regulating the hypothalamic-pituitary-gonadal axis. It is produced by two main groups of neurons in the hypothalamus: the rostral periventricular region around the third ventricle and the arcuate nucleus. Kiss is the peptide product of the KiSS-1 gene and serves as the endogenous agonist for the GPR54 receptor. The Kiss/GPR54 system functions as a critical regulator of the reproductive system. Thus, we examined the effect of intracerebroventricular administration of 3 µg of Kiss to the right lateral ventricle of ovariectomized rats primed with a dose of 5 µg subcutaneous (sc) of estradiol benzoate (EB). Kiss treatment increased the lordosis quotient at all times tested. However, the lordosis reflex score was comparatively lower yet still significant compared to the control group. To investigate receptor specificity and downstream mechanisms on lordosis, we infused 10 µg of GPR54 receptor antagonist, Kiss-234, 5 µg of the progestin receptor antagonist, RU486, or 3 µg of antide, a gonadotropin-releasing hormone-1 (GnRH-1) receptor antagonist, to the right lateral ventricle 30 min before an infusion of 3 µg of Kiss. Results demonstrated a significant reduction in the facilitation of lordosis behavior by Kiss at 60 and 120 min when Kiss-234, RU486, or antide were administered. These findings suggest that Kiss stimulates lordosis expression by activating GPR54 receptors on GnRH neurons and that Kiss/GPR54 system is an essential intermediary by which progesterone activates GnRH.
Subject(s)
Estradiol , Kisspeptins , Receptors, LHRH , Receptors, Progesterone , Sexual Behavior, Animal , Animals , Kisspeptins/pharmacology , Kisspeptins/metabolism , Female , Sexual Behavior, Animal/drug effects , Sexual Behavior, Animal/physiology , Receptors, LHRH/antagonists & inhibitors , Receptors, LHRH/metabolism , Rats , Estradiol/pharmacology , Estradiol/analogs & derivatives , Receptors, Progesterone/metabolism , Receptors, Progesterone/drug effects , Receptors, Progesterone/antagonists & inhibitors , Ovariectomy , Rats, Wistar , Progesterone/pharmacology , Hormone Antagonists/pharmacology , Posture/physiology , Receptors, Kisspeptin-1/metabolism , Mifepristone/pharmacologyABSTRACT
The present study investigated the participation of the nitric oxide pathway in facilitating lordosis behavior induced by intrahypothalamic administration of apelin-13 in ovariectomized rats primed with estradiol benzoate (EB). The experiments involved the administration of a nitric oxide synthase inhibitor (L-NAME) or a nitric oxide-dependent, soluble guanylyl cyclase inhibitor (ODQ), and an inhibitor of protein kinase G (KT5823) to the ventromedial hypothalamus (VMH) of EB-primed rats 30 min before infusion of apelin-13 (0.75 µg/µl). This dose of apelin-13 consistently induces lordosis behavior at 30 min, 120 min, and 240 min following infusion. Results showed that injections of either L-NAME or KT5823 significantly reduced the lordosis induced by apelin at 120 and 240 min. However, VMH infusion of ODQ 30 min before apelin-13 infusion reduced but did not significantly inhibit, the lordosis elicited by this peptide at the same time points. We conclude that the nitric oxide pathway in the VMH plays an important role in lordosis induced by apelin-13 in EB-primed rats.
Subject(s)
Lordosis , Nitric Oxide , Rats , Female , Animals , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide/metabolism , Lordosis/chemically induced , Sexual Behavior, Animal/physiology , Estradiol/pharmacologyABSTRACT
Intracerebroventricular (ICV) administration of estradiol benzoate (E2B) and progesterone (P) induces intense lordosis behavior in ovariectomized rats primed peripherally with E2B. The present study tested the hypothesis that the Kisspeptin (Kiss) and melanin-concentrating hormone (MCH) pathways regulate female sexual behavior induced by these steroid hormones. In Experiment 1, we tested the relevance of the Kiss pathway by ICV infusion of its inhibitor, kiss-234, before administration of E2B or P in estrogen-primed rats. Lordosis induced by E2B alone or with the addition of P was reduced significantly at 30, 120, and 240 min. In Experiment 2, ICV infusion of MCH 30 min before E2B or P significantly reduced lordosis in rats primed with E2B alone. These data support the hypothesis that the Kiss and MCH pathways, which can release or modulate gonadotropin-releasing hormone (GnRH), are involved in E2B- and P-induced lordosis.
Subject(s)
Lordosis , Progesterone , Animals , Female , Rats , Estradiol/pharmacology , Gonadotropin-Releasing Hormone/pharmacology , Kisspeptins/pharmacology , Lordosis/chemically induced , Ovariectomy , Progesterone/pharmacology , Sexual Behavior, Animal/physiologyABSTRACT
In normal hormonal conditions, increased neuronal activity in the ventromedial hypothalamus (VMH) induces lordosis whereas activation of the preoptic area (POA) exerts an opposite effect. In the present work, we explored the effect of bilateral infusion of different doses of the apelin-13 (0.37, 0.75, 1.5, and 15 µg) in both brain areas on the expression of lordosis behavior. Lordosis quotient and lordosis reflex score were performed at 30, 120, and 240 min. Weak lordosis was observed following the 0.37 µg dose of apelin-13 at 30 min in the VMH of EB-primed rats; however, the rest of the doses induced significant lordosis relative to the control group. At 120 min, all doses induced lordosis behavior, while at 240 min, the highest dose of 15 µg did not induce significant differences. Interestingly, only the 0.75 µg infusion of apelin in the POA induced significant lordosis at 120 and 240 min. These results indicate that apelin-13 acts preferably in HVM and slightly in POA to initiate lordosis behavior in estrogen-primed rats.
Subject(s)
Intercellular Signaling Peptides and Proteins , Lordosis , Preoptic Area , Animals , Estradiol/pharmacology , Estrogens/pharmacology , Hypothalamus/drug effects , Hypothalamus/pathology , Intercellular Signaling Peptides and Proteins/pharmacology , Lordosis/chemically induced , Preoptic Area/drug effects , Preoptic Area/pathology , Progesterone/pharmacology , Rats , Sexual Behavior, Animal/drug effects , Ventromedial Hypothalamic Nucleus/drug effects , Ventromedial Hypothalamic Nucleus/pathologyABSTRACT
Intracerebroventricular (icv) administration of oxytocin (OT) induces robust lordosis behavior (lordosis quotient and lordosis intensity) in estrogen-primed rats. The present study explored the hypothesis that the OT-Prostaglandin E2-GnRH pathway (a pathway produced in astrocytes) is involved in the facilitation of lordosis behavior by icv infusion of OT (2 µg). In Experiment 1, we tested the involvement of the OT receptor (OTR) by infusion of the OTR antagonist, atosiban (ATO). OT-induced lordosis was significantly reduced at both 30 and 120 min by prior infusion of ATO. In Experiment 2, we studied the effects of aspirin (COX2 inhibitor) and ONO-AE3-208 (ONO; EP4 prostaglandin receptor antagonist) on OT-induced lordosis. Infusions of both compounds diminished OT-induced lordosis at both 120 and 240 min. In Experiment 3, the involvement of the GnRH-1 receptor inhibitor antide on OT-induced lordosis was evaluated. Antide significantly inhibited OT-induced lordosis at all times tested. These data indicate that the OT/PGE2/GnRH pathway is involved in the expression of OT-induced lordosis behavior, an effect that may be occurring directly in hypothalamic astrocytes.
Subject(s)
Dinoprostone , Lordosis , Animals , Dinoprostone/pharmacology , Female , Gonadotropin-Releasing Hormone/metabolism , Gonadotropin-Releasing Hormone/pharmacology , Lordosis/chemically induced , Oxytocin/pharmacology , Rats , Rats, Sprague-Dawley , Sexual Behavior, AnimalABSTRACT
Activation of progesterone receptor (PR) facilitates lordosis 40â¯hr after estradiol treatment, but induces concurrent inhibition (CI) when given with estradiol, or sequential inhibition (SI) when given subsequent to the faciliatory time interval. Tibolone (TBL) is a broad spectrum gonadal steroid agonist that facilitates lordosis when given after estradiol and in place of progesterone (P). The present experiment examined whether it can also induce CI or SI of lordosis behavior in rats as a means of determining its dominant receptor mechanism of action. Subcutaneous (SC) injections of estradiol benzoate (EB), TBL, or P were varied in time to examine whether P induced CI in females pre-treated with TBL or EB, or whether P or TBL induced CI when injected prior to EB (Experiment 1); whether P or TBL induced SI after EB treatment (Experiment 2); and whether P induced SI after TBL treatment (Experiment 3). In Experiment 1, P injected 1â¯h before EB induced CI after a second P administration 40â¯h later. However, the same treatment of P to females primed with TBL did not induce CI. In Experiment 2, injections of P or TBL 40â¯h after EB or TBL induced lordosis within 4â¯h (facilitation test); however, a second injection of P, 24â¯h later, induced significant lordosis in rat pretreated with TBL, but not in rats pretreated with P (inhibition test). In Experiment 3, P injected 40â¯hs after different doses of TBL induced intense lordosis behavior (facilitation test); however, a second dose of P injected 64â¯h later induced SI, but not in females primed with the highest dose of TBL (inhibition test). Unlike P, TBL did not induce CI or SI. This suggests that TBL likely induces its facilitation of lordosis by an action that is independent of PR.
Subject(s)
Inhibition, Psychological , Norpregnenes/administration & dosage , Posture/physiology , Sexual Behavior, Animal/drug effects , Sexual Behavior, Animal/physiology , Animals , Contraceptive Agents, Hormonal/administration & dosage , Dose-Response Relationship, Drug , Estradiol/administration & dosage , Estradiol/analogs & derivatives , Female , Injections, Intraventricular , Male , Progesterone/administration & dosage , Progestins/administration & dosage , Rats , Rats, Sprague-DawleyABSTRACT
A dose-response study was made of the broad-spectrum gonadal steroid agonist tibolone (TBL) on lordosis behavior in estradiol benzoate (EB: 5 µg) primed rats. Doses of TBL (0, 1, 4, and 16 µg) were infused to the right lateral ventricle 2 h before testing. The highest dose increased lordosis quotients significantly at 240 min and 360 min following infusion. However, the intensity of lordosis was weak. In experiment 2, the TBL dose of 16 µg was selected to determine whether tamoxifen (TMX), RU486, or antide could modify the lordosis response to TBL. Infusions of the three compounds, before TBL, significantly attenuated the TBL-induced facilitation of lordosis. The results suggest that TBL stimulates lordosis by activating estrogen, progesterone, and may do so by downstream stimulation of GnRH release. The physiological role TBL plays in controlling lordosis behavior remains to be determined.
Subject(s)
Estrogen Receptor Modulators/pharmacology , Norpregnenes/pharmacology , Posture , Sexual Behavior, Animal/drug effects , Animals , Estradiol/analogs & derivatives , Estradiol/pharmacology , Female , Hormone Antagonists/pharmacology , Mifepristone/pharmacology , Oligopeptides/pharmacology , Rats , Rats, Sprague-Dawley , Receptors, Estrogen/antagonists & inhibitors , Receptors, LHRH/antagonists & inhibitors , Receptors, Progesterone/antagonists & inhibitorsABSTRACT
An injection of unesterified oestradiol (E2 ) facilitates receptive behaviour in E2 benzoate (EB)-primed, ovariectomised female rats when it is administered i.c.v. or systemically. The present study tested the hypothesis that inhibitors of protein kinase A (PKA), protein kinase G (PKG) or the Src/mitogen-activated protein kinase (MAPK) complex interfere with E2 facilitation of receptive behaviour. In Experiment 1, lordosis induced by i.c.v. infusion of E2 was significantly reduced by i.c.v. administration of Rp-cAMPS, a PKA inhibitor, KT5823, a PKG inhibitor, and PP2 and PD98059, Src and MAPK inhibitors, respectively, between 30 and 240 minutes after infusion. In Experiment 2, we determined whether the ventromedial hypothalamus (VMH) is one of the neural sites at which those intracellular pathways participate in lordosis behaviour induced by E2 . Administration of each of the four protein kinase inhibitors into the VMH blocked facilitation of lordosis induced by infusion of E2 also into the VMH. These data support the hypothesis that activation of several protein kinase pathways is involved in the facilitation of lordosis by E2 in EB-primed rats.
Subject(s)
Estrogen Antagonists/pharmacology , Lordosis/physiopathology , Protein Kinase Inhibitors/pharmacology , Ventromedial Hypothalamic Nucleus/physiology , Animals , Carbazoles/pharmacology , Cyclic AMP/analogs & derivatives , Cyclic AMP/pharmacology , Estradiol/physiology , Female , Flavonoids/pharmacology , Infusions, Intraventricular , Lordosis/chemically induced , Male , Microinjections , Protein Kinase Inhibitors/administration & dosage , Pyrimidines/pharmacology , Rats , Thionucleotides/pharmacology , Ventromedial Hypothalamic Nucleus/drug effectsABSTRACT
Parturient rats show a postpartum estrus, a period of sexual receptivity that occurs from 6 to 15â¯h after the birth of a litter, which allows the mother to gestate a second litter while simultaneously nursing the first one (lactating and pregnant). The present study investigated hormone levels and the expression pattern of estrogen receptor α, and ß, progesterone receptor isoforms and SRC1 in the hypothalamus and the preoptic area of lactating as well as in lactating-pregnant rats. In the latter, estradiol levels were 3-fold higher than those observed in lactating rats on day 14, meanwhile progesterone levels did not change in any condition. There were higher levels of prolactin in both lactating and lactating-pregnant rats on day 7 and decreased on the following days. In the hypothalamus of the lactating rat, the content of ERα increased during lactation meanwhile that of ERß decreased 50% on day 10. The content of both estrogen receptor subtypes in the hypothalamus increased 3-fold on day 21 in lactating-pregnant rats. In the preoptic area, the content of ERα was higher in lactating-pregnant rats on days 14 and 21 while the content of progesterone receptor isoforms was lower as compared with those found in lactating animals on days 7 and 10. The content of SRC1 increased 2-fold in the preoptic area only in lactating rats at day 14 and 21. These findings suggest that lactating- pregnant animals should exhibit differential neuroendocrine and molecular characteristics as compared to lactating animals.
Subject(s)
Gonadal Steroid Hormones/metabolism , Lactation , Receptors, Estrogen/metabolism , Receptors, Progesterone/metabolism , Animals , Female , Pregnancy , Rats , Rats, Sprague-DawleyABSTRACT
The present study was designed to assess the participation of estrogen receptors alpha (ERα) and beta (ERß) in the short-term facilitation of lordosis behavior in ovariectomized (ovx), estradiol (E2) primed rats. In experiment 1, dose response curves for PPT and DPN (ERα and ERß agonists, respectively) facilitation of lordosis behavior (lordosis quotient and lordosis score) were established by infusing these agonists into the right lateral ventricle (icv) in female rats injected 40h previously with 5µg of E2 benzoate. PPT doses of 0.08 and 0.4ng produced high lordosis quotients starting at 30min and continuing at 120 and 240min post-injection. DPN induced high levels of lordosis behavior at all times tested. However, the intensity of lordosis induced by both agonists was weak. In experiment 2, we tested the involvement of each ER in facilitation of lordosis by icv infusion of MPP (ERα-selective antagonist) or PHTPP (ERß-selective antagonist) prior to infusion of 2ng of free E2. Icv infusion of either MPP or PHTPP 30min before free E2 significantly depressed E2 facilitation of lordosis. The results suggest that both forms of ER are involved in the short-latency facilitation of lordosis behavior in E2-primed rats.
Subject(s)
Estrogen Receptor alpha/physiology , Estrogen Receptor beta/physiology , Posture/physiology , Sexual Behavior, Animal/physiology , Animals , Estradiol/pharmacology , Estrogen Receptor alpha/agonists , Estrogen Receptor beta/agonists , Estrous Cycle/drug effects , Estrous Cycle/physiology , Female , Male , Ovariectomy , Rats , Rats, Sprague-Dawley , Sexual Behavior, Animal/drug effectsABSTRACT
An investigation of aspects ranging from behavior to molecular electronic structure and physicochemical properties was performed to explore the role of 5α-pregnanedione (5α-DHP), 5ß-pregnanedione (5ß-DHP) and their precursor progesterone (P) on the concurrent inhibition of the sexual lordosis response in female rats. The concurrent inhibition of lordosis behavior occurs when ovariectomized rodents are primed simultaneously with estradiol (E2) and P. Thus, a second administration of P 40h later fails to induce the expected sexual response that takes place when E2 and P are administered sequentially 40h apart. In this study, it is hypothesized that the modulation of the sexual behavior display depends to some extent on the molecular structure and associated physicochemical properties of steroid hormones such as P and its metabolites. Therefore, these molecules must be studied chemically and structurally to explain their role in sexual behavior, including the concurrent inhibition effect. Analysis of the electronic structure and physicochemical properties demonstrated striking differences in the A-ring region of P, 5α-DHP and 5ß-DHP, particularly in atomic charges, dipole moment (DM) and electrostatic potentials. Similarly, the structural differences between the trans (5α-DHP) and cis (5ß-DHP) configurations were remarkable. 5α-DHP most significantly promoted the concurrent inhibition of the lordosis behavior, followed by P and 5ß-DHP. These data indicate that variations in pregnane structure are related to the extent of the concurrent inhibition effect and also suggest that P may act as a prehormone in certain functions of the central nervous system.
Subject(s)
5-alpha-Dihydroprogesterone/pharmacology , Estradiol/pharmacology , Progesterone/pharmacology , Sexual Behavior, Animal/drug effects , Animals , Female , Male , Ovariectomy , Rats , Rats, Sprague-Dawley , Sexual Behavior, Animal/physiology , Stereoisomerism , Stereotaxic Techniques , Structure-Activity Relationship , Time FactorsABSTRACT
In some conditions, female sexual behavior in ovariectomized rats can be induced by continuous exposure of estradiol (E2) alone or by a single injection of a high dose of the long-lasting, esterified estradiol benzoate (EB). However, there are inconsistencies in the literature on the role of estrogens during priming or in the facilitation on female sexual behavior in EB-primed rats, as well as the cellular mechanisms involved. Either subcutaneous (sc) or intracerebral (icv) administration of some doses of free unesterified E2, induced lordosis in EB-primed rats. Either sc or icv injection of E2, immediately prior to testing, induced high levels of sexual receptivity when the female rats were primed with an EB sc injection of 2 µg EB. The roles of progesterone receptor (PR) and estrogen receptor on lordosis induced by sc or icv administration of E2 were explored. Tamoxifen or RU486 administrated sc or icv; each reduced lordosis induced by E2. Similarly, antisense oligonucleotides directed at PR-B or total PR (PR-A + PR-B) administrated icv immediately before EB injection inhibited lordosis induced by daily injections of EB. These results suggest that lordosis facilitated by free E2 is dependent on priming dose of EB. Furthermore both ERs and PRs are involved in this action of E2.
Subject(s)
Estradiol/analogs & derivatives , Psychotropic Drugs/administration & dosage , Receptors, Estrogen/metabolism , Receptors, Progesterone/metabolism , Sexual Behavior, Animal/drug effects , Animals , Dose-Response Relationship, Drug , Estradiol/administration & dosage , Estrogen Antagonists/pharmacology , Female , Hormone Antagonists/pharmacology , Mifepristone/pharmacology , Oligonucleotides, Antisense/administration & dosage , Ovariectomy , Posture/physiology , Rats, Sprague-Dawley , Receptors, Estrogen/antagonists & inhibitors , Receptors, Progesterone/antagonists & inhibitors , Sexual Behavior, Animal/physiology , Tamoxifen/pharmacology , Time FactorsABSTRACT
The present study tested the hypothesis that the Janus kinase 2, Src tyrosine kinases, and mitogen-activated protein kinase interact to regulate lordosis behavior induced by leptin in ovariectomized, estrogen-primed rats. The role of protein kinase A and protein kinase C in lordosis facilitation by leptin was also assessed. In experiment 1, the intracerebroventricular administration of leptin to ovariectomized, estradiol-primed rats significantly stimulated lordosis behavior at 1, 2 and 4 h post-injection tests. In experiment 2, the Janus kinase 2 inhibitor AG490, the Src tyrosine kinase inhibitor PP2 and the mitogen-activated protein kinase inhibitor PD98059 were administered into the right lateral ventricle before leptin. The lordosis quotient and the lordosis score induced by leptin were significantly decreased by each of these kinase inhibitors. In experiment 3, we examined the effects of RpcAMPS and bisindolylmaleimide, protein kinase A and protein kinase C inhibitors on the lordosis elicited by leptin administration. Lordosis behavior induced by leptin was significantly decreased by both the protein kinase A and protein kinase C inhibitors at 1 h post-leptin injection. The results confirm that multiple intracellular pathways participate in the expression of lordosis behavior in estrogen-primed rats elicited by leptin.
Subject(s)
Back/physiology , Estrogens/administration & dosage , Leptin/physiology , Ovariectomy , Protein Kinases/metabolism , Sexual Behavior, Animal , Animals , Female , Infusions, Intraventricular , Leptin/administration & dosage , Rats , Rats, Sprague-DawleyABSTRACT
The progesterone receptor (PR) is a dual function protein that acts in the nucleus as a transcriptional factor and at the cytoplasm as a scaffold for the Src-MAPK signaling pathway. Several agents lacking affinity for the PR, such as 5ß-reduced progestins, GnRH or prostaglandin E(2) (PGE(2)) facilitate estrous behavior in ovariectomized (ovx), estrogen-primed rats yet their action is blocked by the antiprogestin RU486. We hypothesize that these agents act by using the PR-Src-mitogen activated protein kinase alternative pathway. To test this hypothesis we used PP2, a specific inhibitor of the Src kinase family. Intraventricular infusion of 30 µg of PP2, 30 min before behavioral testing, significantly attenuated estrous behaviors induced in estradiol benzoate (E(2)B)-primed rats by 5ß-dihydroprogesterone (5ß-DHP), 5ß-pregnan-3ß-ol-20-one (5ß,3ß-Pgl), GnRH, PGE(2) and by manual flank/vaginocervical stimulation. These results suggest that the Src signaling system, by activating mitogen-activated protein kinases, participates in the facilitation of estrous behavior in E(2)B-primed rats induced by agents lacking affinity for the PR.
Subject(s)
Dinoprostone/pharmacology , Estradiol/pharmacology , Estrus/drug effects , Gonadotropin-Releasing Hormone/pharmacology , Progestins/pharmacology , Sexual Behavior, Animal/drug effects , src-Family Kinases/physiology , Animals , Cervix Uteri/drug effects , Drug Administration Schedule , Estradiol/administration & dosage , Female , Physical Stimulation , Progestins/chemistry , Rats , Rats, Sprague-Dawley , Signal Transduction/drug effects , Signal Transduction/physiology , Vagina/drug effects , Vagina/physiology , src-Family Kinases/metabolismABSTRACT
Intracerebroventricular (icv) administration of leptin facilitates lordosis behavior in ad libitum-fed, estrogen-primed rats. The cellular mechanism involved in this response is unknown. The present study tested the hypothesis that the nitric oxide-guanylyl cyclase, cGMP-dependent protein kinase (PKG) pathway is involved in the facilitation of lordosis behavior induced by the central administration of leptin. We tested the importance of the nitric oxide/cGMP pathway for lordosis stimulation by either icv infusion of a nitric oxide synthase inhibitor (L-NAME) or a nitric oxide-dependent, soluble guanylyl cyclase inhibitor (ODQ) 30 min before leptin administration (1 µg). This dose of leptin reliably induced lordosis behavior in ovariectomized estradiol benzoate treated rats. The lordosis induced by leptin at 1 and 2h after infusion was significantly reduced by the previous injection of either L-NAME or by ODQ. Intracerebroventricular infusion of the PKG inhibitor (KT5823) 30 min before leptin infusion, also significantly inhibited the lordosis behavior induced by leptin at 1 and 2h after hormone administration. These data support the hypothesis that the nitric oxide/cGMP/PKG pathway is involved in the facilitation of lordosis by leptin in estrogen-primed female rats.
Subject(s)
Cyclic GMP-Dependent Protein Kinases/metabolism , Leptin/administration & dosage , Nitric Oxide/metabolism , Sexual Behavior, Animal , Animals , Carbazoles/pharmacology , Cyclic GMP-Dependent Protein Kinases/antagonists & inhibitors , Female , Guanylate Cyclase/pharmacology , Leptin/pharmacology , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide/physiology , Ovariectomy , Posture , Rats , Rats, Sprague-Dawley , Receptors, Cytoplasmic and Nuclear/pharmacology , Soluble Guanylyl CyclaseABSTRACT
Progesterone exerts a variety of actions in the brain through the interaction with its receptors (PR) which have two isoforms with different function and regulation: PR-A and PR-B. Progesterone may modulate neurotransmission by regulating the expression of neurotransmitters synthesizing enzymes or their receptors in several brain regions. The role of PR isoforms in this modulation is unknown. We explored the role of PR isoforms in the regulation of tryptophan (TPH) and tyrosine (TH) hydroxylase, and glutamic acid decarboxylase (GAD) expression in the hypothalamus of ovariectomized rats. Two weeks after ovariectomy, animals were subcutaneously injected with 5 µg of estradiol benzoate (EB), and 40 h later, progesterone (P) was intracerebroventricularly (ICV) injected. Each animal received two ICV injections of 1 µg/µl (4 nmol) of PR-B and total PR (PR-A+PR-B) sense or antisense (As) oligonucleotides (ODNs). First injection was made immediately before sc EB injection, and 24h later animals received the second one. Twenty-four hours after P administration, rats were euthanized and brains removed to measure the expression of PR-A and PR-B, TPH, TH and GAD by Western blot. We observed that sense ODNs modified neither PR isoforms nor enzymes expression in the hypothalamus, whereas PR A+B antisense (PR A+B As) clearly decreased the expression of both PR isoforms in this region. ICV administration of PR-B As only decreased PR-B isoform expression with no significant effects on PR-A expression. A differential protein expression of TPH, TH and GAD was observed after PR isoforms antisense administration. PR-B As administration decreased the expression of TPH (65% with respect to control). In contrast, PR A+B As and PR-B As administration increased (51.6% and 34.4%, respectively) TH expression. The administration of PR A+B As and PR-B As diminished GAD expression (33.4% and 41.6%, respectively). Our findings indicate that PR isoforms play a differential role in the regulation of the content of TPH, TH and GAD in the rat hypothalamus.
Subject(s)
Glutamate Decarboxylase/biosynthesis , Hypothalamus/enzymology , Receptors, Progesterone/metabolism , Tryptophan Hydroxylase/biosynthesis , Tyrosine 3-Monooxygenase/biosynthesis , Animals , Blotting, Western , Estradiol/analogs & derivatives , Estradiol/pharmacology , Female , Gene Expression Regulation, Enzymologic/drug effects , Gene Expression Regulation, Enzymologic/physiology , Hypothalamus/drug effects , Injections, Intraventricular , Isomerism , Oligonucleotides, Antisense , Ovariectomy , Rats , Rats, Sprague-Dawley , Receptors, Progesterone/chemistry , Receptors, Progesterone/drug effectsABSTRACT
The effect of genital stimulation, either by vaginocervical stimulation (VCS) using a calibrated vaginal probe combined with manual flank stimulation (FS), or by mounts performed by the male, on the hypothalamus and preoptic area concentration of the progesterone receptors A (PR-A) and B (PR-B) was assessed in ovariectomized (ovx) estrogen-primed rats. VCS/FS or stimulation provided by male mounts, even without intromission, significantly decreased PR-B concentration in the hypoythalamus. Down regulation of PR produced by genital stimulation was quantitatively similar to that elicited by progesterone (P) administration. Bilateral or unilateral transection of the pelvic or the pudendal nerves prevented down regulation elicited by VCS/FS. Repeated VCS/FS elicited lordosis behavior in most ovx estrogen primed rats, but the lordosis intensity was lower than that observed in response to P. P administered to ovx estrogen primed rats, induced sequential inhibition, i.e., failure to display estrous behavior in response to a second P injection (24h after the initial P injection). VCS/FS failed to elicit sequential inhibition, since rats responded with normal estrous behavior to the second injection of P. This suggests that down regulation by VCS, by contrast with P, failed to inhibit the subpopulation of PR involved in the facilitation of estrous behavior by P.
Subject(s)
Brain/metabolism , Estrus/drug effects , Progesterone/pharmacology , Receptors, Progesterone/metabolism , Vagina/innervation , Animals , Brain/anatomy & histology , Brain/drug effects , Dose-Response Relationship, Drug , Female , Male , Ovariectomy , Physical Stimulation/methods , Rats , Rats, Sprague-Dawley , Sexual Behavior, Animal/drug effects , Sexual Behavior, Animal/physiology , Statistics, Nonparametric , Time Factors , Vagina/drug effectsABSTRACT
Dose response curves for leptin facilitation of estrous behavior (lordosis and proceptivity) were made by infusing the peptide into the lateral ventricle (icv) of ovariectomized (ovx), ad libitum-fed rats injected 40h previously with 5µg of estradiol benzoate. Leptin doses of 1 and 3µg produced significant lordosis quotient at 60min post-injection, with maximal lordosis being displayed at 120min. Yet the intensity of lordosis was weak, and a high incidence of rejection behaviors was found. Moreover, leptin did not induce significant proceptive behaviors at any dose. The leptin doses of 1 and 3µg were selected for determining whether antide, a GnRH-1 receptor antagonist, or the progestin receptor antagonist RU486 could modify the lordosis response to leptin. Icv injection of either antide or RU486 1h before leptin significantly depressed leptin facilitation of lordosis. The results suggest that leptin stimulates lordosis by releasing GnRH, which in turn activates GnRH-1 and progestin receptors. The physiological role of leptin in the control of estrous behavior remains to be determined.