Tachykinins are comprised of the family of related peptides, substance P (SP), neurokinin A (NKA), and neurokinin B (NKB). NKB has emerged as regulator of kisspeptin release in the arcuate nucleus (ARC), whereas the roles of SP and NKA in reproduction remain unknown. This work explores the roles of SP and NKA in the central regulation of GnRH release. First, central infusion of specific agonists for the receptors of SP (neurokinin receptor 1, NK1R), NKA (NK2R) and NKB (NK3R) each induced gonadotropin release in adult male and ovariectomized, estradiol-replaced female mice, which was absent in Kiss1r(-/-) mice, indicating a kisspeptin-dependent action. The NK2R agonist, however, decreased LH release in ovariectomized-sham replaced females, as documented for NK3R agonists but in contrast to the NK1R agonist, which further increased LH release. Second, Tac1 (encoding SP and NKA) expression in the ARC and ventromedial nucleus was inhibited by circulating estradiol but did not colocalize with Kiss1 mRNA. Third, about half of isolated ARC Kiss1 neurons expressed Tacr1 (NK1R) and 100% Tacr3 (NK3R); for anteroventral-periventricular Kiss1 neurons and GnRH neurons, approximately one-fourth expressed Tacr1 and one-tenth Tacr3; Tacr2 (NK2R) expression was absent in all cases. Overall, these results identify a potent regulation of gonadotropin release by the SP/NK1R and NKA/NK2R systems in the presence of kisspeptin-Kiss1r signaling, indicating that they may, along with NKB/NK3R, control GnRH release, at least in part through actions on Kiss1 neurons.
Background/Aims: The control of labor pain and the prevention of suffering are major concerns of clinicians and their patients. The aim of this study was to evaluate the effect of music on labor pain and anxiety, maternal hemodynamics, fetal-neonatal parameters and postpartum analgesic requirement in primiparous women. Methods: Overall, 156 primiparous women who expected vaginal delivery were recruited and randomly assigned to a music group (n = 77) or a control group (n = 79). Women in the music group listened to music during labor. Pain intensity and anxiety level were measured using a visual analogue scale (0-10 cm). The two groups were compared in terms of pain severity, anxiety level, maternal hemodynamics, fetal-neonatal parameters and postpartum analgesic requirement. Results: Mothers in the music therapy group had a lower level of pain and anxiety compared with those in the control group at all stages of labor (p < 0.001). A significant difference was observed between the two groups in terms of maternal hemodynamics and fetal heart rate after intervention (p < 0.01). Postpartum analgesic requirement significantly decreased in the music therapy group (p < 0.01). Conclusion: Listening to music during labor has a positive impact on labor pain and anxiety, maternal-fetal parameters and analgesic requirement.
Puberty is a tightly regulated process that leads to reproductive capacity. Kiss1 neurons are crucial in this process by stimulating GnRH, yet how Kiss1 neurons are regulated remains unknown. Substance P (SP), an important neuropeptide in pain perception, induces gonadotropin release in adult mice in a kisspeptin-dependent manner. Here, we assessed whether SP, through binding to its receptor NK1R (neurokinin 1 receptor), participates in the timing of puberty onset and fertility in the mouse. We observed that 1) selective NK1R agonists induce gonadotropin release in prepubertal females; 2) the expression of Tac1 (encoding SP) and Tacr1 (NK1R) in the arcuate nucleus is maximal before puberty, suggesting increased SP tone; 3) repeated exposure to NK1R agonists prepubertally advances puberty onset; and 4) female Tac1(-/-) mice display delayed puberty; moreover, 5) SP deficiency leads to subfertility in females, showing fewer corpora lutea and antral follicles and leading to decreased litter size. Thus, our findings support a role for SP in the stimulation of gonadotropins before puberty, acting via Kiss1 neurons to stimulate GnRH release, and its involvement in the attainment of full reproductive capabilities in female mice.
Objective: To assess the effects of gum chewing on postoperative bowel function after cesarean section. Material and Methods: Women who underwent cesarean section were randomized to either a gum-chewing group (n = 74) or a non-gum-chewing group (n = 76). The two groups were compared with respect to the return of bowel activity, postoperative analgesic and antiemetic drug requirement and postoperative hospital stay. Results: Bowel sounds appeared in a significantly shorter duration of time in the study group, the mean being 5.9 h as compared to 6.7 h in the control group (p < 0.01). The first passage of flatus postoperatively was 22.4 h in the gum-chewing group and 31 h in the control group (p < 0.001). The total length of hospital stay was shorter in the gum-chewing group (2.1 days) than in the control group (2.3 days), but it was not statistically significant (p > 0.05). Postoperative analgesic requirement in both groups was similar, but the postoperative antiemetic need in the gum-chewing group was lower than in the control group (p < 0.01). Conclusion: On the basis of the tolerability and results on bowel function, gum chewing provides a simple method for early recovery of bowel function after cesarean section.
The adipocyte-derived hormone leptin plays a critical role in the central transmission of energy balance to modulate reproductive function. However, the neurocircuitry underlying this interaction remains elusive, in part due to incomplete knowledge of first-order leptin-responsive neurons. To address this gap, we explored the contribution of predominantly inhibitory (GABAergic) neurons versus excitatory (glutamatergic) neurons in the female mouse by selective ablation of the leptin receptor in each neuronal population: VgatCre;Lepr lox/lox mice displayed significantly reduced levels of Kiss1 (but not Tac2) mRNA in the arcuate nucleus, and a reduced compensatory luteinizing hormone increase compared with control animals. Estradiol replacement after ovariectomy inhibited gonadotropin release to a similar extent in both groups. These animals also exhibited a compromised positive feedback response to sex steroids, as shown by significantly lower Kiss1 mRNA levels in the AVPV, compared with Lepr lox/lox mice. We conclude that leptin-responsive GABAergic neurons, but not glutamatergic neurons, act as metabolic sensors to regulate fertility, at least in part through modulatory effects on kisspeptin neurons.
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