尾部静脉注射5-HTP对慢性应激抑郁模型大鼠海马CA1区神经元放电频率的影响

目的研究慢性应激抑郁模型大鼠在尾部静脉注射5-羟色胺酸（5-HTP）后引起的海马CA1区神经元放电的变化.方法给予对照组大鼠及抑郁模型组大鼠尾部静脉注射5-HTP后,用玻璃微电极记录两组海马CA1区神经元的放电变化情况,并对其进行收录及结果分析.结果模型组的兴奋神经元放电频率增加的百分率明显高于正常对照组（P〈0.05）.结论增加大鼠脑内5-HT的含量有助于加强抑郁模型大鼠海马区5-羟色胺酸神经元的兴奋性,改善抑郁症状.     

Peptide cotransmitter at a neuromuscular junction

The neuropeptide proctolin (H-Arg-Tyr-Leu-Pro-Thr-OH) is present in the nerve terminals of an identified slow skeletal motoneuron in the cockroach. Proctolin is released onto the target muscle, a coxal depressor, by neuron stimulation and by depolarization with potassium. The physiological action of the motoneuron suggests that proctolin acts as a cotransmitter. Proctolin and neural stimulation produce delayed and sustained contractile effects without muscle depolarization.     

Ribonucleic acid metabolism of a single neuron: correlation with electrical activity

The giant neuron of the abdominal ganglion of Aplysia californica incorporates tritiated uridine into RNA at a constant rate at rest. This rate incrceases under synaptic stimulation, the increase being directly proportional to the number of action potentials produced by the neuron. Multineuronal samples from stimulated ganglia faiiled to show an increase in incorporation.     

Selective recording and stimulation of individual identified neurons in freely behaving Aplysia

A neuroethological technique is described for selective recording and stimulation of an individual neuron in freely behaving Aplysia by means of a fine wire glued into the connective tissue sheath above the identified cell body. A whole-nerve cuff electrode simultaneously monitored functionally related multiunit axon activity. For biophysical analysis the soma was impaled with a microelectrode when the ganglion was subsequently exposed. The technique is illustrated for several identified neurons involved in different behaviors.     

Generalized neocortical responses and corticospinal neuron activity

Long-latency responses evoked by ipsilateral sciatic nerve and hippocampal-fornix stimulation in barbiturized cats are associated with activation of corticospinal neurons. Differences in latency and configuration of generalized responses and patterns of relayed corticospinal neuron discharges indicate that a variety of extra-thalamic projections are involved in activation of Betz cells.     

Nerve regeneration: correlation of electrical, histological, and behavioral events

Wihtin 5 days after the leg nerves of a cockroach are injured, miniature end-plate potentials have disappeared. and the muscle is unresponsive to electrical stimulation. The soma of the injured neutron has a dense perinuclear ring of RNA. By 40 days after the injury, locomotor activity has returned, and the miniature end-plate potentials and evoked electrical responses have reappeared in the muscle. The RNA ring has disappeared, and the nucleus of the regenerating neuron has shifted to an eccentric position.     

Acetylcholine facilitation, atropine block of synaptic excitation of cortical neurons

Sinigle neurons in cat visual cortex were driven by afferent stimuli to determine the effects of drugs liberated from multibarreled micropipettes on synaptic transmission. Acetylcholine increased, and atropine decreased, the number of neuron discharges fired in response to stimulation of the mesencephalic reticular formation without necessarily affecting responses to other stimuli or affecting spontaneous firing.     

Reciprocal inhibition as indicated by a differential staining reaction

Neurohistological and neurophysiological studies have shown that the bilaterally represented Mauthner's cells in teleosts are related both structurally and functionally. The VIIIth nerve afferents, as well as the axoaxonal collaterals, display a distribution pattern which supports the concept of polar function of the neuron. Inasmuch as it is possible to alter the staining reaction of both the Mauthner's cells by unilateral stimulation of the entering VIIIth nerve roots, it is proposed that the synaptic endings serve principally as activators and that neuronal excitation or inhibition is determined by the chemical state of the dendrites, the cell body, and the axon hillock region.     

Antidromic action potentials fail to demonstrate known interactions between neurons

An identified motor neuron in the stomatogastric ganglion of Panulirus interruptus inhibits four other motor neurons when it fires spontaneously or in response to depolarization of its soma. It does not inhibit these neurons when it is fired antidromically, although the attenuated antidromic spike is visible at its soma. These findings point out the difficulty of interpreting negative results from antidromic stimulation experiments and the importance of neuronal structure to the integrative activities of nervous systems.     

From stimulation to undulation: a neuronal pathway for the control of swimming in the leech

Initiation and performance of the swimming movement in the leech (Hirudo medicinalis) are controlled by neurons organized at at least four functional levels-sensory neurons, gating neurons, oscillator neurons, and motor neurons. A paired neuron, designated as Trl, in the subesophageal ganglion of the leech has now been shown to define a fifth level, interposed between sensory and gating neurons. Cell Trl is activated by pressure and nociceptive mechanosensory neurons, which mediate bodywall stimulus-evoked swimming activity in intact leeches. In the isolated leech nervous system, brief stimulation of cell Trl elicits sustained activation of the gating neurons and triggers the onset of swimmning activity. The synaptic interactions between all five levels of control are direct. Discovery of the Trl cells thus completes the identification of a synaptic pathway by which mechanosensory stimulation leads to the swimming movements of the leech.     

Associative conditioning of single sensory neurons suggests a cellular mechanism for learning

A cellular analog of associative learning has been demonstrated in individual sensory neurons of the tail withdrawal reflex of Aplysia. Sensory cells activated by intracellular current injection shortly before a sensitizing shock to the animal's tail display significantly more facilitation of their monosynaptic connections to a tail motor neuron than cells trained either with intracellular stimulation unpaired to tail shock or with tail shock alone. This associative effect is acquired rapidly and is expressed as a temporally specific amplification of heterosynaptic facilitation. The results suggest that activity-dependent neuromodulation may be a mechanism underlying associative information storage and point to aspects of subcellular processes that might be involved in the formation of neural associations.     

Postsynaptic signaling and plasticity mechanisms

In excitatory synapses of the brain, specific receptors in the postsynaptic membrane lie ready to respond to the release of the neurotransmitter glutamate from the presynaptic terminal. Upon stimulation, these glutamate receptors activate multiple biochemical pathways that transduce signals into the postsynaptic neuron. Different kinds of synaptic activity elicit different patterns of postsynaptic signals that lead to short- or long-lasting strengthening or weakening of synaptic transmission. The complex molecular mechanisms that underlie postsynaptic signaling and plasticity are beginning to emerge.     

楝属川楝素含量与生物活性的关系

本文报道用高速液相色谱测定了川楝素含量的各地楝树样品水提物及几种川楝素产品对菜青虫的生物活性,讨论了川楝素含量与生物活性的关系。叶、果样品中虽不含或仅含少量川楝素,但对试虫仍表现出一定的活性。皮中含有较丰富的川楝素,其含量与拒食活性呈正相关,但与毒效作用不相关。四川样品川楝素含量及生物活性均很高而值得重视。川楝素粗产品相对于纯川楝素而言对试虫具更高的生物活性。这种川楝素含量与活性的非线性关系说明样品中其它成份也具活性或与川楝素有着协同作用。通过测定、分析和讨论,指出用川楝素粗产品防治菜青虫是一经济、有效,可行的措施。文中应用了评判援效型杀虫剂的新方法,供讨论和参考。     

A pertussis toxin-sensitive G protein in hippocampal long-term potentiation

High-frequency (tetanic) stimulation of presynaptic nerve tracts in the hippocampal region of the brain can lead to long-term synaptic potentiation (LTP). Pertussis toxin prevented the development of tetanus-induced LTP in the stratum radiatum-CA1 synaptic system of rat hippocampal slices, indicating that a guanosine triphosphate-binding protein (G protein) may be required for the initiation of LTP. This G protein may be located at a site distinct from the postsynaptic neuron (that is, in presynaptic terminals or glial cells) since maximal activation of CA1 neuronal G proteins by intracellular injection of guanosine-5'-O-(3-thiotriphosphate), a nonhydrolyzable analog of guanosine 5'-triphosphate, did not occlude LTP.     

表没食子儿茶素没食子酸酯（EGCG）生物活性研究进展

综述近年来国内外有关EGCG生物活性的研究进展,着重阐述EGCG在抗氧化、保护神经系统、抗肿瘤及保护心脑血管方面的活性,综述其在免疫、内分泌和代谢酶抑制方面的研究成果,展望这一研究领域的发展前景和发展方向,期望为茶多酚类物质深入研究及产品开发提供思路。     

醋蛋中ACE抑制肽的分离及其活性保护的研究

ACE抑制肽在体内稳定性的研究对于其功能活性的保护具有重要意义。采用凝胶色谱层析法对经酶解后的醋蛋液进行分离纯化,收集具有较高抑制活性的多肽组分。再将其与卵磷脂结合形成复合物,目的是利用卵磷脂的乳化性保护多肽活性。利用FT-IR、XRD对复合物的结合效果进行验证分析,结果发现卵磷脂与活性肽结合后,活性肽的ACE抑制活性在体外模拟前后相较于未经结合处理得到明显的升高。红外光谱研究发现复合物中活性肽与卵磷脂发生相互作用。通过XRD进一步验证并推断是活性多肽被卵磷脂吸收后以无定形或分子态的形式存在。因此,可认为经过卵磷脂复合的多肽可以很好保留ACE抑制活性且可以降低其被胃肠道酶降解的风险。     

Naturally occurring antihormones: secretion of FSH antagonists by women treated with a GnRH analog

Follicle-stimulating hormone (FSH) is a glycoprotein essential for gonadal development and steroidogenesis. Recent studies suggest that deglycosylation of FSH results in the formation of antagonistic proteins that are capable of binding to gonadal receptors but that are devoid of bioactivity. Treatment of hypogonadal women with an antagonist of gonadotropin-releasing hormone substantially decreased serum FSH bioactivity with minimal changes in immunoreactivity. Chromatofocusing and size fractionation of the serum samples indicated the secretion of immunoreactive FSH isoforms that are devoid of bioactivity but that are capable of blocking FSH action in ovarian granulosa cells. These findings provide the first demonstration of naturally occurring circulating antihormones. These FSH antagonists may play an important role in the physiology and pathophysiology of the gonads.     

植物多糖的生物活性研究进展

对植物多糖的生物活性进行了阐述。植物源的多糖类化合物具有免疫调节、抗肿瘤活性、防治动脉粥样硬化作用以及抗病毒、抗氧化和防衰老等作用,其独特的生物活性在临床应用中具有极大的潜力。     

Detection, stimulation, and inhibition of neuronal signals with high-density nanowire transistor arrays

We report electrical properties of hybrid structures consisting of arrays of nanowire field-effect transistors integrated with the individual axons and dendrites of live mammalian neurons, where each nanoscale junction can be used for spatially resolved, highly sensitive detection, stimulation, and/or inhibition of neuronal signal propagation. Arrays of nanowire-neuron junctions enable simultaneous measurement of the rate, amplitude, and shape of signals propagating along individual axons and dendrites. The configuration of nanowire-axon junctions in arrays, as both inputs and outputs, makes possible controlled studies of partial to complete inhibition of signal propagation by both local electrical and chemical stimuli. In addition, nanowire-axon junction arrays were integrated and tested at a level of at least 50 "artificial synapses" per neuron.     

壳聚糖伤口敷料的研究进展

综述壳聚糖的水溶性和生物活性,以及通过壳聚糖制成膜、水凝胶和纤维等形式的伤口敷料方面的研究进展。