Effects of propofol on glutamatergic neuronal activity in paraventricular thalamus / 药学学报

This study explored the effects of propofol on the activity of glutamatergic neurons in the paraventricular thalamus (PVT) and the underlying mechanisms at the molecular level using whole-cell patch-clamp techniques. Acute brain slices containing the PVT were obtained from 8 weeks old C57BL/6J mice. The electrophysiological characteristics of PVT neurons were recorded in current-clamp mode, then single-cell sequencing was used to identify neuronal types. The firing frequencies before, during, and after propofol or intralipid application were recorded as FB, FD and FW; and the membrane potentials were recorded as MPB and MPD. Picrotoxin (PTX) was used to block inhibitory gamma-aminobutyric acid type A (GABAA) receptors during the application of propofol at 10 μmol·L-1. Then, GABAA receptor-mediated spontaneous and miniature inhibitory postsynaptic currents (sIPSCs and mIPSCs) were recorded, and the effects of 10 μmol·L-1 propofol were investigated. The animal experiments were approved by the Medical Animal Administrative Committee of Shanghai Medical College Fudan University. The results showed that there were no significant differences in FB, FD and FW during intralipid and 2 μmol·L-1 propofol application. With propofol at 5, 10 and 20 μmol·L-1, FD decreased significantly when compared with FB, and FW increased significantly as compared with FD (P < 0.01). The inhibition degree of the three concentration groups was significantly different (P < 0.01). In addition, with propofol at 20 μmol·L-1, MPD hyperpolarized significantly (P < 0.01). In the presence of PTX, 10 μmol·L-1 propofol could not suppress the firing frequency of PVT glutamatergic neurons. Propofol at 10 μmol·L-1 prolonged the decay time of sIPSCs (P < 0.01) and mIPSCs (P < 0.05), and increased the amplitude (P < 0.01) of mIPSCs of PVT glutamatergic neurons. Together, these results indicate that propofol can inhibit the activity of PVT glutamatergic neurons in a concentration-dependent and reversible manner, and the effect is likely to be mediated by postsynaptic GABAA receptors.

Whole-Brain Monosynaptic Inputs to Hypoglossal Motor Neurons in Mice / 神经科学通报·英文版

Hypoglossal motor neurons (HMNs) innervate tongue muscles and play key roles in a variety of physiological functions, including swallowing, mastication, suckling, vocalization, and respiration. Dysfunction of HMNs is associated with several diseases, such as obstructive sleep apnea (OSA) and sudden infant death syndrome. OSA is a serious breathing disorder associated with the activity of HMNs during different sleep-wake states. Identifying the neural mechanisms by which the state-dependent activities of HMNs are controlled may be helpful in providing a theoretical basis for effective therapy for OSA. However, the presynaptic partners governing the activity of HMNs remain to be elucidated. In the present study, we used a cell-type-specific retrograde tracing system based on a modified rabies virus along with a Cre/loxP gene-expression strategy to map the whole-brain monosynaptic inputs to HMNs in mice. We identified 53 nuclei targeting HMNs from six brain regions: the amygdala, hypothalamus, midbrain, pons, medulla, and cerebellum. We discovered that GABAergic neurons in the central amygdaloid nucleus, as well as calretinin neurons in the parasubthalamic nucleus, sent monosynaptic projections to HMNs. In addition, HMNs received direct inputs from several regions associated with respiration, such as the pre-Botzinger complex, parabrachial nucleus, nucleus of the solitary tract, and hypothalamus. Some regions engaged in sleep-wake regulation (the parafacial zone, parabrachial nucleus, ventral medulla, sublaterodorsal tegmental nucleus, dorsal raphe nucleus, periaqueductal gray, and hypothalamus) also provided primary inputs to HMNs. These results contribute to further elucidating the neural circuits underlying disorders caused by the dysfunction of HMNs.

Role of stress in depression insomnia and sleep characteristics of commonly used animal stress models / 药学学报

Depression and insomnia are intimately related. Depressed patients usually manifest sleep discontinuity and early awakening, reduced or no slow wave sleep (SWS) and shortened latency of rapid eye movement (REM) sleep. These sleep abnormalities are very similar to those caused by over activated hypothalamic-pituitary-adrenal (HPA) axis with stress. Therefore, the animal models developed by post-traumatic stress disorder or chronic unpredictable mild stress could be used to evaluate drugs which have effects of both anti-depression and improvement of sleep quality, and to provide a more reliable platform for further studis on the mechanisms of depression and accompanied insomnia. This review mainly focuses on the typical features of sleep disturbance of depression, possible pathophysiological mechanisms, establishment of animal stress models and analysis of their abnormal sleep characteristics.

Advances in the study of histaminergic systems and sleep-wake regulation / 药学学报

Histaminergic neurons solely originate from the tuberomammillary nucleus (TMN) in the posterior hypothalamus and send widespread projections to the whole brain. Experiments in rats show that histamine release in the central nervous system is positively correlated with wakefulness and the histamine released is 4 times higher during wake episodes than during sleep episodes. Endogeneous prostaglandin E2 and orexin activate histaminergic neurons in the TMN to release histamine and promote wakefulness. Conversely, prostaglandin D2 and adenosine inhibit histamine release by increasing GABA release in the TMN to induce sleep. This paper reviews the effects and mechanisms of action of the histaminergic system on sleep-wake regulation, and briefly discusses the possibility of developing novel sedative-hypnotics and wakefulness-promoting drugs related to the histaminergic system.

CLONING OF NATTOKINASE GENE AND EXPRESSION IN E. COLI / 微生物学通报

In this study, nattokinase gene was amplified by PCR using bacillus subtilis chromosomal DNA as template and cloned into expressed vector pBV220. After transforming recombinant plasmid into E.coli HB101, the recombinant strain was yielded. It was proved that expression products was secretive and expression protein was 12% of total cell protein by SDS-PAGE. Optimum culture time and inducing time was determined as 6h and 5h respectively. The plasmid stability studies showed that recombinant plasmid has excellent segregational stability but the structural stability was not good in the host cell.