Grounded in the theory of "all marrows dominated by brain", this study explored the therapeutic mechanism of Zuogui Pills in modulating the oxytocin(OXT)/oxytocin receptor(OXTR) feed-forward loop in the treatment of postmenopausal osteoporosis(PMOP). A PMOP rat model was established using ovariectomy, and 70 Sprague-Dawley female rats were randomly divided into the following groups: sham operation group, model group, estradiol group(17β-estradiol, 0.05 mg·kg~(-1)·d~(-1)), Zuogui Pills low, medium, and high dose groups(0.2, 0.4, 0.8 g·kg~(-1)·d~(-1), respectively), and an antagonist group(atosiban 0.9 mg·kg~(-1)·d~(-1) + 17β-estradiol 0.05 mg·kg~(-1)·d~(-1) + Zuogui Pills 0.4 g·kg~(-1)·d~(-1)). After 12 weeks of model establishment, treatment was administered by gavage once daily for another 12 weeks, followed by sample collection. Enzyme-linked immunosorbent assay(ELISA) was used to measure serum levels of estrogen(E_2), OXT, tartrate-resistant acid phosphatase(TRACP-5b), and bone alkaline phosphatase(BALP). Histopathological changes in the left distal femur were observed through hematoxylin and eosin(HE) staining. Micro-computed tomography(micro-CT) was used to analyze the microstructure of the right distal femur. Western blot was employed to detect the expression levels of OXTR, small GTP-binding protein Ras, Raf1 proto-oncogene(Raf1), mitogen-activated protein kinase kinase 1/2(MEK1/2), and extracellular signal-regulated kinase 1/2(ERK1/2), and their phosphorylated forms in tibial tissues. Compared with the model group, the Zuogui Pills medium and high dose groups showed significantly increased levels of E_2, OXT, and BALP, with a notable decrease in TRACP-5b levels. Morphologically, the trabeculae in the left distal femur were more tightly arranged. The fibrous structure in the right distal femur was significantly improved in the Zuogui Pills high dose group. Additionally, the expression of OXTR, Ras, p-Raf1, p-MEK1/2, and p-ERK1/2 proteins in tibial tissues was significantly increased. The therapeutic effect of the Zuogui Pills high dose group was partially inhibited when an OXTR antagonist was administered. These findings suggest that Zuogui Pills can regulate the OXT/OXTR feed-forward loop, activate the phosphorylation of the downstream Ras/Raf1/MEK/ERK signaling pathway, and ultimately improve bone mineral density, thereby exerting therapeutic effects in PMOP.
Animals ; Rats, Sprague-Dawley ; Rats ; Female ; Drugs, Chinese Herbal/administration & dosage* ; Oxytocin/genetics* ; Receptors, Oxytocin/genetics* ; Humans ; Osteoporosis, Postmenopausal/genetics* ; Bone and Bones/drug effects* ; Brain/drug effects* ; Bone Marrow/drug effects*

The oxytocin receptor (OXTR) has garnered increasing attention for its role in regulating both mature behaviors and brain development. It has been established that OXTR mediates a range of effects that are region-specific or period-specific. However, the current studies of OXTR expression patterns in mice only provide limited help due to limitations in resolution. Therefore, our objective was to generate a comprehensive, high-resolution spatiotemporal expression map of Oxtr mRNA across the entire developing mouse brain. We applied RNAscope in situ hybridization to investigate the spatiotemporal expression pattern of Oxtr in the brains of male mice at six distinct postnatal developmental stages (P7, P14, P21, P28, P42, P56). We provide detailed descriptions of Oxtr expression patterns in key brain regions, including the cortex, basal forebrain, hippocampus, and amygdaloid complex, with a focus on the precise localization of Oxtr⁺ cells and the variance of expression between different neurons. Furthermore, we identified some neuronal populations with high Oxtr expression levels that have been little studied, including glutamatergic neurons in the ventral dentate gyrus, Vgat⁺Oxtr⁺ cells in the basal forebrain, and GABAergic neurons in layers 4/5 of the cortex. Our study provides a novel perspective for understanding the distribution of Oxtr and encourages further investigations into its functions.
Animals ; Receptors, Oxytocin/metabolism* ; Male ; Brain/growth & development* ; Mice ; Mice, Inbred C57BL ; Neurons/metabolism* ; Single-Cell Analysis ; Gene Expression Regulation, Developmental ; RNA, Messenger/metabolism* ; Animals, Newborn

Oxytocin is classically termed a 'prosocial neuropeptide' because of its evolutionarily conserved role in promoting affiliative behaviors. Endogenous oxytocin is mainly synthesized by hypothalamic oxytocin neurons and signals through oxytocin receptors (OxtRs). Recent studies with cell type-specific and circuit-specific interrogation have uncovered that oxytocin signals exert pleiotropic neuromodulatory effects through anatomically widespread axonal projections and ubiquitously distributed OxtRs. Dysfunctions of oxytocin signals are closely relevant to brain disorders/diseases. While intranasal oxytocin administration has been demonstrated to be one potential strategy to alleviate some brain disorders/diseases, such as autism, obesity, and anxiety, conflicting clinical outcomes highlight the imperative for precision-targeted neuromodulation strategies. Dissecting the molecular, cellular, and neural circuitry mechanisms underlying oxytocinergic modulation is a prerequisite to achieving this goal. This review provides an overview of the current understanding of the oxytocin system in terms of anatomical structure, neuronal modulation, and signal pathways, and discusses the modulatory roles of oxytocin in social, feeding, emotional, and sensory-related brain functions and brain diseases.
Oxytocin/metabolism* ; Humans ; Animals ; Hypothalamus/physiology* ; Brain/physiology* ; Brain Diseases/physiopathology* ; Receptors, Oxytocin/metabolism*

Empathy is crucial for communication and survival for individuals. Whether empathy in pain contagion shows sex differences and its underlying mechanisms remain unclear. Here, we report that pain contagion can occur in stranger female rats, but not in stranger males. Blocking oxytocin receptors in the anterior cingulate cortex (ACC) suppressed pain contagion in female strangers, while oxytocin administration induced pain contagion in male strangers. In vitro, corticosterone reduces neuronal activation by oxytocin. During male stranger interactions, higher corticosterone decreased oxytocin receptor-positive neuronal activity in the ACC, suppressing pain contagion. These findings highlight the role of oxytocin in pain contagion and suggest that sex differences in empathy may be determined by the balance of oxytocin and corticosterone in the ACC. This study suggests an approach for the treatment of certain mental disorders associated with abnormal empathy, such as autism and depression.
Animals ; Oxytocin/pharmacology* ; Gyrus Cinguli/drug effects* ; Male ; Female ; Corticosterone/pharmacology* ; Empathy/drug effects* ; Sex Characteristics ; Receptors, Oxytocin/antagonists & inhibitors* ; Pain/psychology* ; Rats ; Rats, Sprague-Dawley ; Neurons/metabolism*

OBJECTIVE: Corticotropin-releasing hormone (CRH) is a crucial regulator of human pregnancy and parturition. Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels are important for regulating myometrial quiescence during pregnancy. We investigated regulatory effects of different concentrations of CRH on KATP channel expression in human myometrial smooth muscle cells (HSMCs) in in vitro conditions. METHODS: After treating HSMCs with different concentrations of CRH (1, 10, 102, 103, 104 pmol/L), mRNA and protein expression of KATP channel subunits (Kir6.1 and SUR2B) was analyzed by reverse transcription-polymerase chain reaction and western blot. We investigated which CRH receptor was involved in the reaction and measured the effects of CRH on intracellular Ca2+ concentration when oxytocin was administered in HSMCs using Fluo-8 AM ester. RESULTS: When HSMCs were treated with low (1 pmol/L) and high (103, 104 pmol/L) CRH concentrations, KATP channel expression significantly increased and decreased, respectively. SUR2B mRNA expression at low and high CRH concentrations was significantly antagonized by antalarmin (CRH receptor-1 antagonist) and astressin 2b (CRH receptor-2 antagonist), respectively; however, Kir6.1 mRNA expression was not affected. After oxytocin treatment, the intracellular Ca2+ concentration in CRH-treated HSMCs was significantly lowered in low concentration of CRH (1 pmol/L), but not in high concentration of CRH (103 pmol/L), compared to control. CONCLUSION: Our data demonstrated the regulatory effect was different when HSMCs were treated with low (early pregnancy-like) and high (labor-like) CRH concentrations and the KATP channel expression showed significant increase and decrease. This could cause inhibition and activation, respectively, of uterine muscle contraction, demonstrating opposite dual actions of CRH.
Adenosine Triphosphate ; Adenosine ; Animals ; Blotting, Western ; Corticotropin-Releasing Hormone ; Female ; Humans ; In Vitro Techniques ; KATP Channels ; Mice ; Myocytes, Smooth Muscle ; Myometrium ; Oxytocin ; Parturition ; Potassium Channels ; Potassium ; Pregnancy ; Receptors, Corticotropin-Releasing Hormone ; RNA, Messenger

OBJECTIVE: Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairment in social skills and communication with repetitive behaviors. Etiology is still unclear although it is thought to develop with interaction of genes and environmental factors. Oxytocin has extensive effects on intrauterine brain development. Vitamin D, affects neural development and differentiation and contributes to the regulation of around 900 genes including oxytocin receptor gene. In the present study, the contribution of D vitamin receptor and oxytocin receptor gene polymorphisms in the development of ASD in Turkish community was investigated. To our knowledge, this is the first study examining these two associated genes together in the literature. METHODS: Eighty-five patients diagnosed with ASD according to DSM-5 who were referred to outpatient clinics of Child and Adolescent Psychiatry of Başkent University and Mersin University and 52 healthy, age and gender-matched controls were included in the present study. Vitamin D receptor gene rs731236 (Taq1), rs2228570 (Fok1), rs1544410 (Bsm1), rs7975232 (Apa1) polymorphisms and oxytocin receptor gene rs1042778 and rs2268493 polymorphisms were investigated using real time polymerase chain reaction method. RESULTS: No significant difference between groups in terms of distribution of genotype and alleles in each of polymorphisms for these genes could be found. CONCLUSION: Knowledge of genes and polymorphisms associated with the development of ASD may be beneficial for early diagnosis and future treatment. Further studies with larger populations are required to demonstrate molecular pathways which may play part in the development of ASD in Turkey.
Adolescent ; Adolescent Psychiatry ; Alleles ; Ambulatory Care Facilities ; Autism Spectrum Disorder ; Brain ; Child* ; Early Diagnosis ; Genotype ; Humans ; Methods ; Neurodevelopmental Disorders ; Oxytocin* ; Polymorphism, Genetic ; Real-Time Polymerase Chain Reaction ; Receptors, Calcitriol ; Receptors, Oxytocin* ; Social Skills ; Turkey ; Vitamin D* ; Vitamins*

Recent studies have provided several lines of evidence that peripheral administration of oxytocin induces analgesia in human and rodents. However, the exact underlying mechanism of analgesia still remains elusive. In the present study, we aimed to identify which receptor could mediate the analgesic effect of intraperitoneal injection of oxytocin and its cellular mechanisms in thermal pain behavior. We found that oxytocin-induced analgesia could be reversed by d(CH₂)₅[Tyr(Me)²,Dab⁵] AVP, a vasopressin-1a (V1a) receptor antagonist, but not by desGly-NH₂-d(CH₂)₅[DTyr², Thr⁴]OVT, an oxytocin receptor antagonist. Single cell RT-PCR analysis revealed that V1a receptor, compared to oxytocin, vasopressin-1b and vasopressin-2 receptors, was more profoundly expressed in dorsal root ganglion (DRG) neurons and the expression of V1a receptor was predominant in transient receptor potential vanilloid 1 (TRPV1)-expressing DRG neurons. Fura-2 based calcium imaging experiments showed that capsaicin-induced calcium transient was significantly inhibited by oxytocin and that such inhibition was reversed by V1a receptor antagonist. Additionally, whole cell patch clamp recording demonstrated that oxytocin significantly increased potassium conductance via V1a receptor in DRG neurons. Taken together, our findings suggest that analgesic effects produced by peripheral administration of oxytocin were attributable to the activation of V1a receptor, resulting in reduction of TRPV1 activity and enhancement of potassium conductance in DRG neurons.
Analgesia* ; Calcium ; Diagnosis-Related Groups ; Electrophysiology ; Fura-2 ; Ganglia, Spinal* ; Humans ; Injections, Intraperitoneal ; Neurons ; Oxytocin* ; Potassium* ; Receptors, Oxytocin ; Receptors, Vasopressin ; Rodentia ; Spinal Nerve Roots*

OBJECTIVETo analyze the level of the oxytocin (OT) and the expression of oxytocin receptor (OTR) in males with idiopathic infertility.

METHODSSixty-five infertile males aged 20 -45 years were divided according to their semen parameters into an idiopathic oligozoospermia group (OG, n = 20), an idiopathic asthenozoospermia group (AG, n = 25), and an idiopathic oligoasthenozoospermia group (OAG, n = 20). Another twenty 20-45 years old healthy male volunteers with a natural childbearing history were included in the control group (CG). All the subjects were detected for the contents of luteinizing hormone (LH), follicle stimulating hormone (FSH) , testosterone (T) and OT, and analyzed for the expression of OTR by sequencing the functional region of the OTR promoter (OTRP), OTR-mRNA, and OTR-COOH terminus. The gene sequences were compared using DNASTAR-MegAlign, Western blot values changed into enumeration data, and all the data analyzed by one-way ANOVA and Dunnette's multiple range t-test.

RESULTSA significantly lower content of OT was observed in CG ( [79.30 +/- 3.83] pg/ml) than in OG ([118.53 +/- 7.69] pg/ml, AG ([108.81 +/- 5.66] pg/ml) and OAG ([103.71 +/- 4.54] pg/ml) (F(0.05/2[2,82]) = 8.29, P < 0.01). The content of LH was significantly lower in AG ([4.26 +/- 0.31] IU/L) and OAG ([4.55 +/- 0.40] IU/L) than in OG ([6.77 +/- 0.57] IU/L) and CG ([7.19 +/- 0.50] IU/L) (F(0.05/2 [2,82]) = 11.64, P < 0.01), and so was the content of FSH in AG ( [5.02 + 0.39] IU/L) than in CG ([8.91 +/- 0.91] IU/L), OG ([11.86 +/- 1.76] IU/L) and OAG ([8.82 +/- 1.03] IU/L) (F(0.05/[2,82]) = 7.22, P < 0.01). There were no significant differences in the T content among the four groups (F(0.05/2[2,82] = 0.42, P = 0.739). No evident gene mutation was found in OTRP and OTR-mRNA gene sequencing. Human OTRs in the lymphocytes were monomers and oligomers, mostly tetramers and hexamers. There were obviously more monomers in AG (0.41 +/- 0.03) and OAG (0.13 +/- 0.01) than in OG (0.05 +/- 0.004) and CG (0.05 +/- 0.003) (F(0.05/2[2,82]) = 115.50, P < 0.01), while the number of oligomers was markedly decreased in 20% of the cases in AG.

CONCLUSIONSignificant differences in the content of OT and expression of OTR between fertile and infertile men suggested an association of OT with male infertility. The decreased expression of OTR oligomers and increased expression of monomers may be related to idiopathic asthenozoospermia, which has provided a new insight into the pathogenesis and treatment of male infertility.

Adult ; Case-Control Studies ; Humans ; Infertility, Male ; metabolism ; pathology ; Male ; Middle Aged ; Neuropeptides ; metabolism ; Oxytocin ; metabolism ; Receptors, Oxytocin ; metabolism ; Young Adult

OBJECTIVETo probe the mechanism of acupuncture in treatment of dysmenorrhea.

METHODSAdult mice with no pregnancy were randomly divided into a normal group, a model group, an acupuncture group and a medication group. The model group, the acupuncture group and the medication group were modeled by Diethylstilbestrol and Ocytocin. For the acupuncture group, at the 7th day of modeling, acupuncture was given at "Sanyinjiao" (SP 6), "Diji" (SP 8), once a day, for 5 days; and at the 7th day of modeling, Yimucao Gao 0.6 mg/g was given intragastrically to the medication group for 5 days. The stretching latent period and the number of stretching within 30 min were observed, and mRNA levels of ocytocin receptor (OctR) and vasopressin receptor (VasR) in the uterus tissue were detected with RT-PCR method.

RESULTSCompared with the model group, the stretching latent period extended (P < 0.05) and the number of stretching within 30 min significantly decreased (P < 0.05); and there were significant differences in the mRNA levels of ocytocin receptor and vasopressin receptor in the uterus tissue in the model group as compared with those in other 3 groups (P < 0.05, P < 0.01).

CONCLUSIONAcupuncture can improve the dysmenorrheal symptom to a certain extent, and the mechanism is possibly related to regulative effects of acupuncture on hormones-mediating receptors in mice.

Acupuncture Therapy ; Animals ; Dysmenorrhea ; metabolism ; therapy ; Female ; Mice ; RNA, Messenger ; analysis ; Receptors, Oxytocin ; genetics ; Receptors, Vasopressin ; genetics

OBJECTIVETo observe the influence of silencing Connexin43 (Cx43) expression of partial acupoints on acupuncture effect, so as to probe into the mechanism of acupuncture treatment for primary dysmenorrhea.

METHODSThe primary dysmenorrheal rat model made by oxytocin and RNA interference (RNAi) technology was used to silence the expression of Cx43 in acupoints. Fifty SD female rats were divided into five groups, a normal group (N), a model group (M), an acupuncture group (A), an acupuncture plus interference group (A+I), an acupuncture plus interference control group (A+IC). RT-PCR method was used to observe the oxytocin receptor (OTR) and vasopressin receptor (VPR) mRNA expressions in the uterus in each group. Plasma prostaglandin E2 (PGE2) and PGF2alpha levels were detected by radioimmunoassay and ELISA, respectively.

RESULTS(1) The times of writhing body (9.43 +/- 3.87 and 10.28 +/- 4.23) were significantly lower and the latency period of writhing body (12.43 +/- 3.46, 11.00 +/- 3.65) were longer in the group A and the group A+IC as compared with (15.43 +/- 5.13, 17.00 +/- 3.87) and (7.57 +/- 1.99, 8.43 +/- 2.57) in the group M and group A+I (P < 0.05), respectively. (2) The levels of Cx43 mR NA level and protein expression of acupoint in the group A+I were significantly lower than those of the group N (P < 0.05). (3) OTR and VPR mRNA in the uterus in the group A and the group A+IC were significantly lower than those in the group M and the group A+I (P < 0.05), with no significant difference between the group M and the group A+I (P > 0.05). (4) As compared with the group M, PGE2 level increased and PGF2alpha level decreased in the group A and the group A+IC (P < 0.05).

CONCLUSIONSilencing Cx43 expression of partial acupoint can inhibit effectively the effect of acupuncture through decreasing OTR and VPR in endometrium of the dysmenorrheal rat and adjusting the prostaglandins (PGs) synthesis system, which possibly is one of the mechanisms of acupuncture for treatment of primary dysmenorrhea.

Acupuncture Points ; Acupuncture Therapy ; Animals ; Connexin 43 ; genetics ; metabolism ; Dinoprost ; blood ; Dinoprostone ; blood ; Dysmenorrhea ; genetics ; metabolism ; therapy ; Female ; Gene Expression ; Humans ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Oxytocin ; genetics ; metabolism ; Receptors, Vasopressin ; genetics ; metabolism ; Uterus ; metabolism