[Correlation analysis of Sema4D with rheumatoid arthritis disease activity, bone destruction and rheumatoid arthritis-related interstitial lung disease].

Objective: To explore the correlation between Semaphorin 4D (Sema4D) and rheumatoid arthritis (RA) clinical manifestations, laboratory indexes, bone destruction and rheumatoid arthritis related interstitial lung disease(RA-ILD), and to analyze its significance in evaluating the severity of patients with rheumatoid arthritis. Methods: A total of 108 RA patients and 50 healthy controls from September 2018 to October 2019 were collected from the Department of Rheumatology and Immunology, Peking University People's Hospital and Beijing Haidian Hospital. According to the DAS 28 score, RA patients were divided into active disease group (DAS28>2.6) and stable disease group (DAS28 ≤ 2.6). Fifty healthy controls. The levels of Sema4D in serum were detected by enzyme-linked immunoassay method (ELISA), and their correlation with clinical manifestations of RA, laboratory indicators, degree of bone damage and RA-ILD were analyzed. Results: The level of serum Sema4D in RA active group was significantly higher than that in stable group and healthy control group (P<0.05). The concentration serum Sema4D was positively correlated with C-reactive protein(CRP) (r=0.28, P<0.05), rheumatoid factor(RF) (r=0.25, P<0.05) and the 28-joint disease activity score (DAS28) (r=0.45, P<0.01). The concentration serum Sema4D was positively correlated with ß-Crosslaps(r=0.20, P<0.05) and Sharp-van der Heijde score (SHS)(r=0.13, P<0.05). The concentration serum Sema4D was positively correlated with Vascular endothelial growth factor (VEGF)(r=0.25, P<0.05) and Warrick score of chest CT in RA patients(r=0.27, P<0.05). The anti-cyclic citrullinated peptid(CCP) antibody, DAS28, VEGF and the incidence of RA-ILD were significantly higher than that in Sema4D negative group (P<0.05). Conclusions: Serum Sema4D level in RA patients is closely related to the disease activity, bone destruction and RA-ILD. Serum Sema4D can be used as an indicator of disease monitoring and prognosis evaluation in RA patients.

Correlation of serum albumin with the clinical features and prognosis of preterm neonates in the neonatal intensive care unit.

OBJECTIVE: To evaluate the clinical significance of serum albumin (ALB) levels in the early evaluation and prognosis of preterm infants in the neonatal intensive care units (NICUs). MATERIALS AND METHODS: The authors collected and retrospectively analyzed complete clinical records of preterm infants admitted to the NICU from July 2012 to March 2013. The cases were divided into three groups according to their ALB levels: ≥ 30 g/L, 25-30 g/L, and ≤ 25 g/L. RESULTS: The mean gestational age in the ≤ 25 g/L ALB group was significantly higher than that in the ≥ 30 g/L ALB group [(33.41 ± 2.15) weeks] (p < 0.05). The prealbumin, blood platelet, and blood urea nitrogen in the ≤ 25 g/L ALB group were significantly lower than those in the ≥ 30 g/L ALB group (p < 0.05). In addition, serum lactate in the ≤ 25 g/L ALB group was significantly higher than that in the ≥ 30 g/L ALB group (p < 0.05). CONCLUSION: Serum ALB level increased with increasing gestational age. Lower ALB levels were associated with more perinatal complications, damage to multiple organs, more severe cases, and mechanical ventilation, which resulted in longer hospital stays and poorer prognoses.

Molecular characteristic and expression analysis of collagenolytic serine protease from the Chinese mitten crab Eriocheir sinensis with defense response to Vibrio anguillarum challenge.

A novel collagenolytic serine protease (CLSP) was cloned from the hemocytes of the Chinese mitten crab Eriocheir sinensis (Es-CLSP). The full-length cDNA of Es-CLSP contains 990 nucleotides. It encodes a 270-amino acid-long peptide with the mature peptide containing 221 amino acids. It contains the conserved catalytic triad (H, D, and S). Similarity analysis shows that Es-CLSP shares high identity with CLSPs from the fiddler crab Uca pugilator. Es-CLSP mRNA expression in E. sinensis is a) tissue-related with the highest expression in hemocytes and widely distributed, b) highly responsive to Vibrio anguillarum challenge in hemocytes, and c) a different response to the intruding pathogens. The results of this study demonstrate the successful isolation of Es-CLSP and indicate that Es-CLSP is an immune-related gene, and show the possible role of CLSP in the invertebrate innate immune system.

[Analysis of risk factors of mortality in infants and toddlers with moderate to severe pediatric acute respiratory distress syndrome].

Objective: To identify the risk factors in mortality of pediatric acute respiratory distress syndrome (PARDS) in pediatric intensive care unit (PICU). Methods: Second analysis of the data collected in the "efficacy of pulmonary surfactant (PS) in the treatment of children with moderate to severe PARDS" program. Retrospective case summary of the risk factors of mortality of children with moderate to severe PARDS who admitted in 14 participating tertiary PICU between December 2016 to December 2021. Differences in general condition, underlying diseases, oxygenation index, and mechanical ventilation were compared after the group was divided by survival at PICU discharge. When comparing between groups, the Mann-Whitney U test was used for measurement data, and the chi-square test was used for counting data. Receiver Operating Characteristic (ROC) curves were used to assess the accuracy of oxygen index (OI) in predicting mortality. Multivariate Logistic regression analysis was used to identify the risk factors for mortality. Results: Among 101 children with moderate to severe PARDS, 63 (62.4%) were males, 38 (37.6%) were females, aged (12±8) months. There were 23 cases in the non-survival group and 78 cases in the survival group. The combined rates of underlying diseases (52.2% (12/23) vs. 29.5% (23/78), χ2=4.04, P=0.045) and immune deficiency (30.4% (7/23) vs. 11.5% (9/78), χ2=4.76, P=0.029) in non-survival patients were significantly higher than those in survival patients, while the use of pulmonary surfactant (PS) was significantly lower (8.7% (2/23) vs. 41.0% (32/78), χ2=8.31, P=0.004). No significant differences existed in age, sex, pediatric critical illness score, etiology of PARDS, mechanical ventilation mode and fluid balance within 72 h (all P>0.05). OI on the first day (11.9(8.3, 17.1) vs.15.5(11.7, 23.0)), the second day (10.1(7.6, 16.6) vs.14.8(9.3, 26.2)) and the third day (9.2(6.6, 16.6) vs. 16.7(11.2, 31.4)) after PARDS identified were all higher in non-survival group compared to survival group (Z=-2.70, -2.52, -3.79 respectively, all P<0.05), and the improvement of OI in non-survival group was worse (0.03(-0.32, 0.31) vs. 0.32(-0.02, 0.56), Z=-2.49, P=0.013). ROC curve analysis showed that the OI on the thind day was more appropriate in predicting in-hospital mortality (area under the curve= 0.76, standard error 0.05,95%CI 0.65-0.87,P<0.001). When OI was set at 11.1, the sensitivity was 78.3% (95%CI 58.1%-90.3%), and the specificity was 60.3% (95%CI 49.2%-70.4%). Multivariate Logistic regression analysis showed that after adjusting for age, sex, pediatric critical illness score and fluid load within 72 h, no use of PS (OR=11.26, 95%CI 2.19-57.95, P=0.004), OI value on the third day (OR=7.93, 95%CI 1.51-41.69, P=0.014), and companied with immunodeficiency (OR=4.72, 95%CI 1.17-19.02, P=0.029) were independent risk factors for mortality in children with PARDS. Conclusions: The mortality of patients with moderate to severe PARDS is high, and immunodeficiency, no use of PS and OI on the third day after PARDS identified are the independent risk factors related to mortality. The OI on the third day after PARDS identified could be used to predict mortality.

Intracranial Hemorrhage in Term and Late-Preterm Neonates: An Institutional Perspective.

BACKGROUND AND PURPOSE: Distribution of intracranial hemorrhage in term and late-preterm neonates is relatively unexplored. This descriptive study examines the MR imaging-detectable spectrum of intracranial hemorrhage in this population and potential risk factors. MATERIALS AND METHODS: Prevalence and distribution of intracranial hemorrhage in consecutive term/late-preterm neonates who underwent brain MR imaging between January 2011 to August 2018 were assessed. MRIs were analyzed to determine intracranial hemorrhage distribution (intraventricular, subarachnoid, subdural, intraparenchymal, and subpial/leptomeningeal), and chart review was performed for potential clinical risk factors. RESULTS: Of 725 term/late-preterm neonates who underwent brain MR imaging, intracranial hemorrhage occurred in 63 (9%). Fifty-two (83%) had multicompartment intracranial hemorrhage. Intraventricular and subdural were the most common hemorrhage locations, found in 41 (65%) and 39 (62%) neonates, respectively. Intraparenchymal hemorrhage occurred in 33 (52%); subpial, in 19 (30%); subarachnoid, in 12 (19%); and epidural, in 2 (3%) neonates. Twenty infants (32%) were delivered via cesarean delivery, and 5 (8%), via instrumented delivery. Cortical vein thromboses were present in 34 (54%); periventricular or medullary vein thromboses, in 37 (59%); and cerebral venous sinus thrombosis, in 5 (8%). Thirty-seven (59%) had elevated markers of coagulopathy (international normalized ratio > 1.2, fibrinogen level < 234), 9 (14%) had a clinically meaningful elevation in the international normalized ratio (>1.4), and 3 (5%) had a clinically meaningful decrease in the fibrinogen level (<150). Three (5%) neonates had thrombocytopenia (platelet count < 100 × 103/µL). CONCLUSIONS: While relatively infrequent, there was a wide distribution of intracranial hemorrhage in term and late-preterm infants; intraventricular and subdural hemorrhages were the most common types. We report a high prevalence of venous congestion or thromboses accompanying neonatal intracranial hemorrhage.

Brain Diffusion Abnormalities in Children with Tension-Type and Migraine-Type Headaches.

BACKGROUND AND PURPOSE: Tension-type and migraine-type headaches are the most common chronic paroxysmal disorders of childhood. The goal of this study was to compare regional cerebral volumes and diffusion in tension-type and migraine-type headaches against published controls. MATERIALS AND METHODS: Patients evaluated for tension-type or migraine-type headache without aura from May 2014 to July 2016 in a single center were retrospectively reviewed. Thirty-two patients with tension-type headache and 23 with migraine-type headache at an average of 4 months after diagnosis were enrolled. All patients underwent DWI at 3T before the start of pharmacotherapy. Using atlas-based DWI analysis, we determined regional volumetric and diffusion properties in the cerebral cortex, thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala, nucleus accumbens, brain stem, and cerebral white matter. Multivariate analysis of covariance was used to test for differences between controls and patients with tension-type and migraine-type headaches. RESULTS: There were no significant differences in regional brain volumes between the groups. Patients with tension-type and migraine-type headaches showed significantly increased ADC in the hippocampus and brain stem compared with controls. Additionally, only patients with migraine-type headache showed significantly increased ADC in the thalamus and a trend toward increased ADC in the amygdala compared with controls. CONCLUSIONS: This study identifies early cerebral diffusion changes in patients with tension-type and migraine-type headaches compared with controls. The hypothesized mechanisms of nociception in migraine-type and tension-type headaches may explain the findings as a precursor to structural changes seen in adult patients with chronic headache.

[A multicenter clinical study on 1 138 cases of invasive pneumococcal disease in children from 2012 to 2017].

Objective: To explore the clinical features, the serotype distribution and drug resistance of the isolates in patient with invasive pneumococcal disease (IPD). Methods: By retrieving the laboratory information system in 18 children's hospitals from 2012 to 2017, the children with IPD were enrolled. Streptococcus pneumoniae (Spn) must be isolated from the sterile sites (blood, cerebrospinal fluid, hydrothorax and joint effusion etc.). The clinical characteristics, serotype, drug resistance, treatment and prognosis were reviewed and analyzed. According to the telephone follow up results, the patients were divided into death group and recovered group. The index as an independent risk factor of mortality was demonstrated by multivariate logistic regression analysis. Results: There were 1 138 children with IPD, including 684 male and 454 female. The proportion of male to female was 1.5∶1. The age ranged from one day to 16 years. The median age was 1 year 3 month. The majority was under 5 years of age (89.3%, n= 1 016), especially under 2 years of age (61.9%, n=704). In all cases, 88.2% (n=1 004) were community acquired infection. The infections included meningitis (n=446, 39.2%), pneumonia with bacteremia (n=339, 29.8%), and bacteremia without focus (n=232, 20.4%). Underlying diseases were found in 242 cases (21.3%). Co-infections were determined in 62 cases (5.4%) with mycoplasma, 27 cases (2.4%) with adenovirus and 34 cases with influenza virus (3.0%). The penicillin insensitivity (PNSP) rates in meningitis and non-meningitis isolates were 69.5% (276/397) and 35.9% (221/615), respectively. There were 81 strains serotyped, in which 93.8% (76/81) were covered by 13-valent protein-polysaccharide conjugate vaccine (PCV13). In the 965 patients who were followed up by phone call, 156 cases (16.2%) were confirmed dead. The independent risk factors for the death were under 2 years of age (OR=2.143, 95%CI 1.284-3.577, P=0.004), meningitis (OR=3.066, 95%CI 1.852-5.074, P<0.01), underlying disease (OR=4.801, 95%CI 2.953-7.804, P<0.01), septic shock(OR=3.542, 95%CI 1.829-6.859, P<0.01), disseminated intravascular coagulation (DIC) (OR=4.150, 95%CI 1.468-11.733, P=0.007), multiple organ failure (OR=12.693, 95%CI 6.623-24.325, P<0.01) and complications of central nervous system (OR=1.975, 95%CI 1.144-3.410, P=0.015). Conclusions: Most children with IPD were under 5 years of age, having underlying diseases and acquired the infection in community. The independent risk factors for death were under two years old, meningitis, underlying diseases and multiple organ failure. The problem of drug resistance was severe. The universal immunization of PCV13 would be effective to prevent IPD in Chinese children.

Nitric oxide via cGMP-dependent mechanisms increases dye coupling and excitability of rat supraoptic nucleus neurons.

Unlike many neuron populations, supraoptic nucleus (SON) neurons are rich in both nitric oxide synthase (NOS) and the NO receptor-soluble guanylyl cyclase (GC), the activation of which leads to cGMP accumulation. Elevations in cGMP result in increased coupling among SON neurons. We investigated the effect of NO on dye coupling in SONs from male, proestrus virgin female, and lactating rats. In 167 slices 263 SON neurons were recorded; 210 of these neurons were injected intracellularly (one neuron per SON) with Lucifer yellow (LY). The typically minimal coupling seen in virgin females was increased nearly fourfold by the NO precursor, L-arginine, or the NO donor, sodium nitroprusside (SNP). L-Arginine-induced coupling was abolished by a NOS inhibitor. In slices from male and lactating rats who have a higher basal incidence of coupling, SNP increased coupling by approximately twofold over control (p < 0.03). SNP effects were prevented by the NO scavenger hemoglobin (20 microM) and by the selective blocker of NO-activated GC, ODQ (10 microM). These results suggest that NO released from cells within the SON can expand the coupled network of neurons and that this action occurs via cGMP-dependent processes. Because increased coupling is associated with elevated SON neuronal excitability, we also studied the effects of 8-bromo-cGMP on excitability. In both phasically and continuously firing neurons 8-bromo-cGMP (1-2 mM), but not cGMP, produced membrane depolarizations accompanied by membrane conductance increases. Conductance increases remained when depolarizations were eliminated by current-clamping the membrane potential. Thus, NO-induced cGMP increases SON neuronal coupling and excitability.

Ionotropic histamine receptors and H2 receptors modulate supraoptic oxytocin neuronal excitability and dye coupling.

Histaminergic neurons of the tuberomammillary nucleus (TM) project monosynaptically to the supraoptic nucleus (SON). This projection remains intact in our hypothalamic slices and permits investigation of both brief synaptic responses and the effects of repetitively activating this pathway. SON oxytocin (OX) neurons respond to single TM stimuli with fast IPSPs, whose kinetics resemble those of GABA(A) or glycine receptors. IPSPs were blocked by the Cl(-) channel blocker picrotoxin, but not by bicuculline or strychnine, and by histamine H(2), but not by H(1) or H(3) receptor antagonists, suggesting the presence of an ionotropic histamine receptor and the possible nonspecificity of currently used H(2) antagonists. G-protein mediation of the IPSPs was ruled out using guanosine 5'-O-(2-thiodiphosphate) (GDP-betaS), pertussis toxin, and Rp-adenosine 3',5'-cyclic monophosphothioate triethylamine (Rp-cAMPs), none of which blocked evoked IPSPs. We also investigated the effects of synaptically released histamine on dye coupling and neuronal excitability. One hundred seventy-three OX neurons were Lucifer yellow-injected in horizontal slices. Repetitive TM stimulation (10 Hz, 5-10 min) reduced coupling, an effect blocked by H(2), but not by H(1) or H(3), receptor antagonists. Because H(2) receptors are linked to activation of adenylyl cyclase, TM-stimulated reduction in coupling was blocked by GDP-betaS, pertussis toxin, and Rp-cAMPs and was mimicked by 8-bromo-cAMP, 3-isobutyl-1-methylxanthine, and Sp-cAMP. Membrane potentials of OX and vasopressin neurons were hyperpolarized, accompanied by decreased conductances, in response to bath application of 8-bromo-cAMP but not the membrane-impermeable cAMP. These results suggest that synaptically released histamine, in addition to evoking fast IPSPs in OX cells, mediates a prolonged decrease in excitability and uncoupling of the neurons.

Chemotherapy plus Erlotinib versus Chemotherapy Alone for Treating Advanced Non-Small Cell Lung Cancer: A Meta-Analysis.

BACKGROUND: Whether a combination of chemotherapy and erlotinib is beneficial for advanced non-small cell lung cancer (NSCLC) remains controversial. This study aimed to summarize the currently available evidence and compare the efficacy and safety of chemotherapy plus erlotinib versus chemotherapy alone for treating advanced NSCLC. METHODS: EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials were searched for relevant studies. Our protocol was registered in PROSPERO (CRD42014015015). RESULTS: Nine randomized controlled trials with a total of 3599 patients were included. Compared to chemotherapy alone, chemotherapy plus erlotinib was superior in PFS (HR = 0.76 [95% CI 0.62, 0.92], P = 0.006), and no statistically significant difference was observed in OS (HR = 0.94 [95% CI 0.86, 1.03], P = 0.16). Intercalated erlotinib plus chemotherapy demonstrated improvements in PFS (HR = 0.67 [95% CI 0.50, 0.91], P = 0.009) and OS (HR = 0.82 [95% CI 0.69, 0.98], P = 0.03). Continuous erlotinib plus chemotherapy treatment failed to demonstrate improvements in PFS (HR = 0.91 [95% CI 0.80, 1.04], P = 0.16) and OS (HR = 0.98 [95% CI 0.89, 1.09], P = 0.75). The association of chemotherapy plus erlotinib with improvement in PFS was significant in never smoking patients (HR = 0.46 [95% CI 0.37, 0.56], P<0.00001) but not in smoking patients (HR = 0.70 [95% CI 0.49, 1.00], P = 0.05). Among patients with EGFR mutant tumors, chemotherapy plus erlotinib demonstrated significant improvements in PFS (HR = 0.31 [95% CI 0.17, 0.58], P = 0.0002) and OS (HR = 0.52 [95% CI 0.30, 0.88], P = 0.01). Among patients with EGFR wild-type tumors, no statistically significant difference was observed with respect to PFS (HR = 0.87 [95% CI 0.70, 1.08], P = 0.21) and OS (HR = 0.78 [95% CI 0.59, 1.01], P = 0.06). CONCLUSION: Combination of chemotherapy and erlotinib is a viable treatment option for patients with NSCLC, especially for patients who never smoked and patients with EGFR mutation-positive disease. In addition, intercalated administration is an effective combinatorial strategy.

Histamine mediates fast synaptic inhibition of rat supraoptic oxytocin neurons via chloride conductance activation.

Axons from the histaminergic neurons of the tuberomammillary nucleus project to both the anterior and tuberal portions of the supraoptic nucleus. Histamine is known to activate vasopressin neurons via a histamine receptor subtype 1 and to increase release of vasopressin, but effects on oxytocin neurons have been previously unexplored. Here we investigated the effects of tuberomammillary nucleus electrical stimulation as well as of histamine antagonists on supraoptic nucleus oxytocin and vasopressin neurons in slices of rat hypothalamus. Electrical stimulation evoked short constant latency (approximately 5 ms), fast (4-6 ms onset to peak) inhibitory postsynaptic potentials in oxytocin neurons and, as shown previously, fast excitatory postsynaptic potentials in vasopressin neurons. These synaptic responses followed paired-pulse stimulus frequencies up to 100 Hz and were, thus, probably reflecting monosynaptic connections. Inhibitory postsynaptic potentials were selectively blocked by histamine receptor subtype 2 antagonists (either cimetidine or famotidine) and by picrotoxin but not by histamine receptor subtype 1 antagonists or bicuculline. Similar synaptic responses to tuberomammillary nucleus stimulation were found in 16 of 16 neurons immunocytochemically identified as oxytocinergic and in seven putative oxytocin neurons. Perifusion of the slice with low chloride medium (4.8 mM) reversed stimulus-evoked inhibitory postsynaptic potentials. We conclude that histaminergic neurons monosynaptically contact both oxytocin and vasopressin cells of the supraoptic nucleus and inhibit the former via activation of chloride channels which can be blocked by the histamine receptor subtype 2 antagonists, famotidine and cimetidine.

Supraoptic nucleus afferents from the main olfactory bulb--II. Intracellularly recorded responses to lateral olfactory tract stimulation in rat brain slices.

To establish the functional nature of the anatomically demonstrated main olfactory bulb inputs to the supraoptic nucleus, electrophysiological responses of intracellularly recorded supraoptic neurons to lateral olfactory tract stimulation were recorded in horizontal slices of basal forebrain and hypothalamus. A total of 71 synaptically influenced neurons were studied in slices from adult rats of both sexes. Of these, 60 cells (84%) were monosynaptically activated by olfactory tract stimulation; seven cells (10%) were activated via polysynaptic pathways; and four cells (6%) were characterized by long latency inhibitory responses. Lucifer Yellow was injected into 64 cells and subsequent immunocytochemical identification of 44 of these neurons showed that both oxytocin and vasopressin cells, in approximately equal numbers, were excited by olfactory stimulation. Polysynaptically mediated excitation, however, was only associated with oxytocin cells (six of the six identified cells). These results corroborate anatomical tract tracing data showing main olfactory bulb efferents to both supraotic neurons and to neurons of the perinuclear zone. Also supported are earlier speculations of olfactory participation in release of oxytocin and vasopressin during various physiological states.

Dye coupling among immunocytochemically identified neurons in the supraoptic nucleus: increased incidence in lactating rats.

The hypothesis that electrotonic spread among oxytocinergic neurons contributes to synchronized bursting in the lactating rat leads to the prediction that coupling among oxytocinergic neurons would be stronger and more abundant in lactating than in non-lactating animals. We tested this prediction using, as an index of electrical coupling, transfer among neurons of the fluorescent dye Lucifer Yellow CH, which crosses gap junctions. Intracellular injections (total of 159) of the dye were made in supraoptic nucleus neurons in hypothalamic slices from virgin female and lactating rats. In virgins, 86 injections resulted in 76 single, 8 coupled pairs and 2 triplets of dye-filled neurons. In contrast, 73 injections in lactators yielded 51 single, 16 coupled pairs and 6 triplets, (greater than 100% increase) a difference significant at P less than 0.001. Immunocytochemical identification of the dye-filled cells revealed that there was an increase over virgins in coupling among both oxytocinergic and vasopressinergic neurons. These results are consistent with the hypothesis that electrical coupling is involved in synchronizing oxytocin cell bursting in lactators. They are also consistent with published data indicating that vasopressin neurons are metabolically activated (show increased glucose uptake) during suckling and may show correlated activity.

Magnocellular tuberomammillary nucleus input to the supraoptic nucleus in the rat: anatomical and in vitro electrophysiological investigations.

Anatomical and electrophysiological methods were used to investigate the existence and role of inputs from the magnocellular tuberomammillary nucleus to the supraoptic nucleus. After injecting either Fluoro-Gold or rhodamine-labeled latex microspheres into the supraoptic nucleus, consistent patterns of retrogradely labeled neurons within the tuberomammillary nucleus were observed. The results indicate that both subdivisions of the supraoptic nucleus, the tuberal and the anterior, receive input from the tuberomammillary nucleus. Injections into the tuberal supraoptic nucleus tended to label more cells in the contralateral tuberomammillary nucleus, while injections into the anterior supraoptic nucleus may label more cells on the ipsilateral side. The in vitro intracellular electrophysiological results support the anatomical findings and extend them in several ways. Some tuberomammillary neurons were found to project to the supraoptic nuclei on both sides of the brain. Intracellular Lucifer Yellow injections into tuberomammillary cells after electrophysiological recording revealed labeled axons that were traceable into the supraoptic nucleus, where apparent varicosities (possible en passant terminals) were seen. Magnocellular tuberomammillary nucleus neurons had characteristic passive and active membrane properties and morphology, similar to histaminergic neurons in this area studied by other workers. Finally, in two of the 21 cases, Lucifer Yellow injection into one neuron revealed dye-coupled pairs of tuberomammillary neurons. Previous work by others has shown that histamine excited cells in the tuberal subdivision of the supraoptic nucleus, stimulating vasopressin release, and that the tuberomammillary nucleus provides histaminergic input to the anterior portion of the supraoptic. The present findings show that the tuberomammillary nucleus supplies input to both subdivisions of the supraoptic nucleus and that this input is provided bilaterally. Taken together with previous work, these data suggest that the tuberomammillary nucleus provides histaminergic input to the supraoptic nucleus and may be involved specifically with vasopressin release.

Electrophysiology of excitatory and inhibitory afferents to rat histaminergic tuberomammillary nucleus neurons from hypothalamic and forebrain sites.

Anatomical evidence exists for projections to the tuberomammillary nucleus (TM) from the nucleus of the diagonal band of Broca (DBB) and the lateral preoptic area (LPO). The physiological effects of activating these inputs were studied by recording postsynaptic responses intracellularly from TM cells during both electrical stimulation and local nanodrop application of glutamate in horizontally cut brain slices. Electrical stimulation of the DBB, LPO and anterior lateral hypothalamic area (LH) usually evoked fast IPSPs (approximately 75% of responses) which were blocked by bicuculline or picrotoxin, suggesting GABA(A) mediation. The remaining excitatory responses evoked by stimulation of the LPO and LH were blocked by non-NMDA receptor antagonists (CNQX or NBQX) and the NMDA receptor antagonist, AP-5. Glutamate applied to the above areas induced postsynaptic responses in TM cells similar to those seen with electrical stimulation. Spontaneous firing in TM cells was suppressed by glutamate applied in the DBB. Glutamate applied in the LPO or LH evoked both inhibitory and excitatory responses. Changes in PSPs and firing rates were interpreted to result from glutamate activation of the neurons in the DBB, LPO and LH areas with inhibitory or excitatory connections to recorded TM neurons. These results support previous anatomical findings and suggest that inhibitory and excitatory synaptic control of TM activity is exerted by the DBB, LPO and LH areas.

Activation of excitatory amino acid inputs to supraoptic neurons. I. Induced increases in dye-coupling in lactating, but not virgin or male rats.

Mitral cells of the main and accessory olfactory bulbs have been shown to project monosynaptically to the supraoptic nucleus (SON) via the lateral olfactory tract (LOT) which uses excitatory amino acid transmitters. Data collected during characterization of these projections suggested that synaptic activation of SON neurons via LOT stimulation in slices influenced the incidence of dye-coupling. The present study pursued this suggestion using horizontally cut slices from male, virgin female and lactating rats. Neurons were confirmed to be excited by electrical stimulation of the tract, injected with Lucifer yellow, and synaptically activated for 10 min at 10 Hz (n = 92). Another 94 neurons were similarly confirmed and injected, but received no further stimulation. In an additional 8 slices, injected neurons were antidromically activated for 10 min at 10 Hz. Analyses done on 194 injected neurons from the 3 groups showed that synaptic activation resulted in a significant (P less than 0.01) increase in the incidence of coupling only in tissue from lactating rats. This increase was entirely due to larger numbers of cells being coupled dendrodendritically to the injected cells in the stimulated slices. Antidromic activation did not influence coupling. Increased coupling occurred among both oxytocin and vasopressin cell types. This is the first report of increased coupling resulting from synaptic activation in mammalian CNS. Changes seen only in lactating rats may be related to their altered SON ultrastructural morphology (i.e. dendritic bundling). Strong olfactory and vomeronasal input associated with some maternal behaviors may increase neuronal coupling and enhance hormone release in response to other incoming stimuli (e.g. suckling, dehydration).

Direct evidence for electrical coupling among rat supraoptic nucleus neurons.

Transfer of the fluorescent dye, Lucifer yellow (LY), from an intracellularly injected neuron to one or more other neurons is accepted as indirect evidence of electrotonic interactions among such dye coupled cells. Direct evidence requires that at least two coupled cells be recorded from simultaneously and such evidence in the CNS has been gained only for hippocampal pyramidal neurons. Since interpretations of the functional significance of dye coupling among magnocellular neuroendocrine cells depend upon its relation to electrical coupling, we sought to obtain direct evidence for electrotonic interactions in such neurons. Over 150 pairs of supraoptic nucleus (SON) neurons in hypothalamic slices were recorded from intracellularly using one LY and one potassium acetate electrode in each instance. Of these, 9 pairs were studied in sufficient detail to determine that they were electrically coupled. Most of the remaining pairs were determined not to be coupled. In each coupled pair of cells, membrane voltage changes due to spontaneously occurring or current evoked action potentials, as well as current evoked hyperpolarizations, in one cell were reflected in similar, though attenuated changes in the other cell. All of these changes occurred simultaneously in the two neurons. Spontaneously arising postsynaptic potentials in the two cells were temporally uncorrelated. In each case that electrical coupling was observed, dye coupling resulted from LY injection. Coupling ratios ranged from 0.05 to 0.2. Capacitative coupling between the recording electrodes as an artifact was ruled out since cells in the same tissue penetration as the coupled cell showed no responses to membrane voltage changes in the primary cell; no responses were seen with the second electrode placed extracellularly or in the medium; and similar coupling potentials were also seen when one cell was recorded without a second electrode present. We conclude that electrical coupling exists among magnocellular neurons of the SON and that the incidence of dye coupling is a reasonable estimate of the incidence of electrical coupling. These electrotonic interactions probably play important roles in the coordination of firing among magnocellular neurosecretory neurons.