Poly(ethylenimine) (PEI) is a synthetic polycation that has been used successfully for gene delivery both in vitro and vivo due, theory, to form of protection afforded the carried plasmids. In this study stability PEI/DNA complexes was demonstrated using deoxyribonuclease (DNase) 1 DNase 2, various levels pH, increasing exposure times. DNA complexed with PEI not degraded when exposed at least 25 Units either enzyme 24 h while uncomplexed forms same plasmid were digested 0.010 0.05 or 0.003 2...

We examined the relationship between presynaptic calcium levels and postsynaptic potentials during normal synaptic transmission, paired-pulse facilitation (PPF), long-term potentiation (LTP) in CA3-CA1 synapses of hippocampus. By selectively loading terminals with indicator fura-2, we simultaneously recorded a (Ca) transient corresponding field EPSP evoked by single stimulus given to Schaffer collateral-commissural pathway guinea pig hippocampal slices. A volume average Ca influx was...

The effects of voltage-dependent Ca channel (VDCC) antagonists on synaptic transmission were investigated at CA3-CA1 synapses guinea pig hippocampal slices. After selectively loading presynaptic structures in area CA1 with the calcium indicator fura-2, we simultaneously recorded a transient ([Ca]t) and corresponding field excitatory postsynaptic potential (fEPSP) evoked by single stimulus given to Schaffer collateral-commissural (SCC) pathway. Application nifedipine did not reduce either...

Neuropeptide Y (NPY) agonists inhibit glutamate release by a presynaptic action at the CA3-CA1 synapse of rat hippocampus. We have examined relationship between [Capre]t via presynaptic, voltage-dependent calcium channels (VDCCs), measured optically using fluorescent indicator fura-2, and transmitter release, electrophysiologically. Activation NPY Y2 receptors reduced thereby inhibited synaptic transmission. Multiple are involved in transmission this synapse. inhibits N-type, P/Q-type,...

Synaptic mechanisms of plasticity are calcium-dependent processes that affected by dysfunction mitochondrial calcium buffering. Recently, we observed mice deficient in voltage-dependent anion channels, the outer component permeability transition pore, have impairments learning and hippocampal synaptic plasticity, suggesting pore is involved plasticity. In this study, examined effect on transmission blocking with low doses cyclosporin A found a deficit an increase base-line transmission....

Synchronized neuronal activity (seizures) can appear in the presence or absence of synaptic transmission. Mechanisms seizure initiation each these conditions have been studied, but relatively few studies addressed termination. In particular, how are seizures terminated where there is no loss excitatory drive augmentation inhibitory inputs? We studied dynamic activity-dependent changes intracellular pH transmission using fluorescent indicator carboxylseminaphthorhodafluo-1. During...

1. The hypothesis that activation of GABAB receptors inhibits evoked synaptic transmission by reducing the presynaptic Ca2+ influx was tested using a recently developed technique for simultaneously recording transient ([Ca2+]t) and field excitatory postsynaptic potential (fEPSP) single electrical stimulus at CA3 to CA1 synapses guinea‐pig hippocampus. 2. receptor agonist baclofen reversibly blocked, in dose‐dependant manner, both fEPSP [Ca2+]t with similar time courses. During application...

A scheme for fast 3-D laser scanning using acousto-optic deflectors is proposed and demonstrated. By employing counterpropagating acoustic waves that are both chirped offset in their frequencies, we show it possible to simultaneously scan axially laterally with frame rates on the order of tens kilohertz. This was specifically designed application multiphoton imaging, particularly neurons, where will enable concurrent monitoring physiological signals at multiple locations within a microscopic...

Fast noninvasive three-dimensional (3D) imaging is crucial for quantitatively studying highly dynamic events ranging from flow cytometry to developmental biology. Light-sheet microscopy has emerged as the tool-of-choice 3D characterization of rapidly evolving systems. However, obtain a image, either sample or parts microscope are moved, limiting acquisition speed. Here, we propose novel inertia-free light-sheet-based scheme volumetric at high temporal resolution. Our approach comprises...

Activation of group I metabotropic glutamate receptors (mGluRs) can induce acute depression excitatory synaptic transmission and long-term (LTD) in area CA1 the rat hippocampus. The underlying mechanisms for both forms are unknown. By measuring presynaptic calcium transients, we show that a reduction stimulation-induced rise triggers vesicular release causes by mGluRs. In contrast, mechanism mGluR-induced LTD does not involve persistent change influx. However, analysis paired-pulse...

Great progress has been made towards understanding the properties of single neurons, yet principles underlying interactions between neurons remain poorly understood. Given that connectivity in neocortex is locally dense through both horizontal and vertical con-nections, it particular importance to characterize activity structure local popula-tions arranged three dimensions. However, techniques for simultaneously measuring microcircuit are lacking. We developed an vivo 3D high-speed,...

Abstract Acoustic waves in an optical medium cause rapid periodic changes the refraction index, leading to diffraction effects. Such acoustically controlled can be used modulate, deflect, and focus light at microsecond timescales, paving way for advanced microscopy designs that feature unprecedented spatiotemporal resolution. In this article, we review operational principles, properties, recent applications of acousto-optic (AO) systems microscopy, including random-access scanning, ultrafast...

The <i>Journal of Biomedical Optics</i> (JBO) is a Gold Open Access journal that publishes peer-reviewed papers on the use novel optical systems and techniques for improved health care biomedical research.

1. The sites of origin spontaneous interictal-like epileptiform activity in hippocampal slices from guinea pig, mouse, and rat were determined. A multisite fast optical recording technique using voltage-sensitive dyes an array 100 photodiodes was employed. use a low-magnification objective lens allowed the visualization almost entire transverse slice. Three vitro models epilepsy employed, utilizing different manipulations bath perfusion medium to induce activity: 1) raising external...

Modulation of presynaptic voltage‐dependent calcium channels (VDCCs) by muscarinic receptors at the CA3–CA1 synapse rat hippocampal slices was investigated using indicator fura‐2. Stimulation‐evoked transients ([Ca pre ] t ) and field excitatory postsynaptic potentials (fe.p.s.ps) were simultaneously recorded. The relationship between influx synaptic transmission studied. Activation inhibited [Ca , thereby reducing transmission. Carbachol (CCh, 10 μ M 35% reduced fe.p.s.p. 85%. inhibition...

Qian, Jing and Peter Saggau. Modulation of transmitter release by action potential duration at the hippocampal CA3-CA1 synapse. J. Neurophysiol. 81: 288–298, 1999. Presynaptic Ca 2+ influx through voltage-dependent channels triggers neurotransmitter release. Action plays a determinant role in dynamics presynaptic influx. In this study, was optically measured with low-affinity indicator (Furaptra). The effect on investigated. K + channel blocker 4-aminopyridine (4-AP) applied to broaden...

Hippocampal μ-opioid receptors (MORs) have been implicated in memory formation associated with opiate drug abuse. MORs modulate hippocampal synaptic plasticity acutely, when chronically activated, and during withdrawal. At the network level, increase excitability area CA1 by disinhibiting pyramidal cells. The precise inhibitory interneuron subtypes affected MOR activation are unknown; however, not all inhibited, specific shown to preferentially express MORs. Here we investigate, using...