Suckling stimuli induce somatodendritic oxytocin (OT) release from supraoptic nucleus (SON) neurons, which raises intranuclear OT concentrations and contributes to the effectiveness of the milk-ejection reflex. To clarify how such changes in OT concentrations modulate the activity of OT neurons, we examined OT effects using whole cell patch-clamp recordings from SON neurons in slices from lactating rats. Progressive increases from extremely low OT concentrations (0.1-10 fM) to high concentrations (0.1-10 nM) induced excitation and subsequent spike frequency reduction (SFR) in OT neurons. Significant effects of OT on firing rates were observed starting at 1 fM, reached peak level from 1 fM to 1 pM before SFR occurred in most neurons. The buildup of OT concentrations progressively promoted depolarization of membrane potential, spike broadening, decreases in spike amplitude, and increases in the rise time of spike afterhyperpolarizations, which were unrelated to firing rate. However, intermittent application of OT (1 fM, 1 pM, and 1 nM, each for 5 min) evoked dose-dependent excitation but not the SFR. Application of 1 pM OT for 40 min simulated the effects of progressively increasing OT concentrations. Vasopressin neurons were also activated by OT but did not show SFR. Consistent with presynaptic loci of OT action, ionotropic glutamate receptor antagonists reduced OT effects on firing rate, whereas bicuculline did not change the excitatory effects. These results suggest that the specific autoregulatory effects of OT, and perhaps other neuropeptides as well, are time and concentration dependent.
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http://dx.doi.org/10.1152/ajpregu.00725.2005 | DOI Listing |
Pulmonary arterial hypertension (PAH) is a chronic progressive exacerbation of cardiopulmonary vascular disease. The patients' exercise endurance decreased progressively and the survival rate was low. Current basic therapy and targeted drug therapy can improve the quality of life (QoL) of PAH patients, but the long-term efficacy and prognosis are not good.
View Article and Find Full Text PDFOpen Life Sci
December 2024
Department of Gastroenterology, The Ninth People's Hospital of Chongqing, No. 69, Jialing Village, Beibei District, Chognqing, 400700, China.
Colorectal cancer (CRC) is a common malignant tumor characterized by a high degree of invasiveness, and since zinc-α2 glycoprotein (ZAG) has been implicated in the progression of several malignancies, this study was designed to investigate the role of ZAG in CRC. Its expression was assessed using the GEPIA database, and short hairpin RNA (shRNA) interference was conducted to create ZAG knockdown in CRC cell lines. We also conducted lipid synthesis, cell proliferation, apoptosis, and epithelial-mesenchymal transition (EMT) experiments to elucidate the effects of ZAG expression on CRC, as well as explored the potential underlying mechanistic pathways.
View Article and Find Full Text PDFObjective: To describe the anatomical and functional outcome of autologous internal limiting membrane (ILM) transplant with 27-gauge plus (27G+) three ports pars plana vitrectomy (PPV) in failed and recurrent full-thickness macular holes (MH) in a spectrum of pathologies.
Study Design: Observational cohort study Methods: Seven eyes of seven patients who had failed or recurrent MH were included from January 2017 to January 2022. A single vitreoretinal surgeon performed all surgeries using a 27G+ PPV system in a tertiary care hospital.
Cureus
December 2024
Department of Cardiology, Japanese Red Cross Maebashi Hospital, Maebashi, JPN.
When encountering severe hypoxemia that does not respond to oxygen supplementation, it is essential to consider underlying right-to-left shunting. Among various diagnostic approaches, the microbubble test via transthoracic echocardiography (TTE) is a simple, noninvasive method for detecting pulmonary arteriovenous shunts, particularly in hepatopulmonary syndrome (HPS). Although microbubbles are usually administered peripherally, using a Swan-Ganz (SG) catheter to inject microbubbles directly into the pulmonary artery may provide even more definitive diagnostic information.
View Article and Find Full Text PDFPan Afr Med J
September 2024
Laboratoire de Biologie et Santé, Faculté des Sciences, Université Ibn-Tofail, Kenitra, Maroc.
Introduction: the purpose of our study is to evaluate the efficacy of azathioprine as first-line treatment in patients with relapsing-remitting multiple sclerosis (RRMS) or progressive multiple sclerosis (PMS), who were supposed to be treated with beta-interferons but, due to limited resources, received azathioprine instead.
Method: among the 31 patients, 17 had relapsing-remitting MS (RRMS), 11 had primary progressive MS (PPMS), and 3 had secondary progressive MS (SPMS). Patients received azathioprine orally at a dose of 3 mg/kg/day over 2 years.
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