Gonadal steroid feedback to oxytocin neurons during pregnancy is in part mediated via the neurosteroid allopregnanolone (3alpha-OH-DHP), acting as allosteric modulator of postsynaptic gamma-aminobutyric acid type A (GABA(A)) receptors. We describe here a form of nongenomic progesterone signaling by showing that 3alpha-OH-DHP not only potentiates GABA(A) receptor-channel activity but also prevents its modulation by protein kinase C (PKC). Application of oxytocin or stimulation of PKC suppressed the postsynaptic GABA responses of oxytocin neurons in the absence, but not in the presence of 3alpha-OH-DHP. This finding was true at the juvenile stage and during late pregnancy, when the GABA(A) receptor is sensitive to 3alpha-OH-DHP. In contrast, after parturition, when the GABA(A) receptors expressed by oxytocin neurons are less sensitive to 3alpha-OH-DHP, this neurosteroid no longer counteracts PKC. The change in GABA(A)-receptor responsiveness to 3alpha-OH-DHP helps to explain the onset of firing activity and thus the induction of oxytocin release at parturition.
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http://dx.doi.org/10.1073/pnas.97.7.3625 | DOI Listing |
Vitam Horm
January 2025
Clinical Research Center, Murayama Medical Center, Musashimurayama, Japan.
The hypothalamus is the gray matter of the ventral portion of the diencephalon. The hypothalamus is the higher center of the autonomic nervous system and is involved in the regulation of various homeostatic mechanisms. It also modulates respiration by facilitating the respiratory network.
View Article and Find Full Text PDFEur J Neurosci
January 2025
Faculty of Medicine, Collegium Medicum, Mazovian Academy in Plock, Plock, Poland.
Chronic migraine (CM) is the ultimate and most burdensome form of the transformation from episodic migraine (EM), called chronification. The mechanism behind migraine chronification is poorly known and difficult to explore as CM has the same spectrum of pathogenesis as EM and the EM-CM transition is bidirectional. Central sensitization (CS) is a key phenomenon in migraine: its mechanisms include disturbed neural plasticity, which is the ability of the nervous system to adapt to endo- and exogenous changes.
View Article and Find Full Text PDFBrain Res
January 2025
Department of Orthopaedics of Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Children's Health, Hangzhou, China. Electronic address:
The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) categorizes postpartum depression (PPD) as a subtype of Major Depressive Disorder (MDD) with peripartum onset, generally arising within the initial trimester following delivery. This acute psychiatric condition is characterized by feelings of worthlessness, insomnia, extreme anxiety, or maternal neglect. Intranasal oxytocin (OT) and transcranial magnetic stimulation (TMS) have the potential to address impaired social cognition; nonetheless, their neuronal underpinnings, along with their safety and efficacy, are little comprehended.
View Article and Find Full Text PDFNat Metab
January 2025
Neuroscience Institute, College of Arts and Sciences, Georgia State University, Atlanta, GA, USA.
Interoception broadly refers to awareness of one's internal milieu. Although the importance of the body-to-brain communication that underlies interoception is implicit, the vagal afferent signalling and corresponding brain circuits that shape perception of the viscera are not entirely clear. Here, we use mice to parse neural circuits subserving interoception of the heart and gut.
View Article and Find Full Text PDFNeurosci Res
January 2025
RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan. Electronic address:
In mammals, lactation is essential for the health and growth of infants and supports the formation of the mother-infant bond. Breastfeeding is mediated by the neurohormone oxytocin (OT), which is released into the bloodstream in a pulsatile manner from OT neurons in the hypothalamus to promote milk ejection into mammary ducts. While classical studies using anesthetized rats have illuminated the activity patterns of putative OT neurons during breastfeeding, the molecular, cellular, and neural circuit mechanisms driving the synchronous pulsatile bursts of OT neurons in response to nipple stimulation remain largely elusive.
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