Simultaneous Optogenetics and Cellular Resolution Calcium Imaging During Active Behavior Using a Miniaturized Microscope.

The ability to precisely monitor and manipulate neural circuits is essential to understand the brain. Advancements over the last decade in optical techniques such as calcium imaging and optogenetics have empowered researchers to gain insight into brain function by systematically manipulating or monitoring defined neural circuits. Combining these cutting-edge techniques enables a more direct mechanism for ascribing neural dynamics to behavior.

Kinetics of oligonucleotide hybridization to DNA probe arrays on high-capacity porous silica substrates.

We have investigated the kinetics of DNA hybridization to oligonucleotide arrays on high-capacity porous silica films that were deposited by two techniques. Films created by spin coating pure colloidal silica suspensions onto a substrate had pores of approximately 23 nm, relatively low porosity (35%), and a surface area of 17 times flat glass (for a 0.3-microm film).

Kinetics of oligonucleotide hybridization to photolithographically patterned DNA arrays.

The hybridization kinetics of oligonucleotide targets to oligonucleotide probe arrays synthesized using photolithographic fabrication methods developed by Affymetrix have been measured. Values for the fundamental adsorption parameters, k(a), k(d), and K, were determined at both room temperature and 45 degrees C by monitoring the hybridization of fluorescently labeled targets to the array. The values for these parameters and the adsorbed target density ( View Article and Find Full Text PDF

Blocks of limited haplotype diversity revealed by high-resolution scanning of human chromosome 21.

Global patterns of human DNA sequence variation (haplotypes) defined by common single nucleotide polymorphisms (SNPs) have important implications for identifying disease associations and human traits. We have used high-density oligonucleotide arrays, in combination with somatic cell genetics, to identify a large fraction of all common human chromosome 21 SNPs and to directly observe the haplotype structure defined by these SNPs. This structure reveals blocks of limited haplotype diversity in which more than 80% of a global human sample can typically be characterized by only three common haplotypes.

Ethanol alters microvasculature enzymes in the rat forebrain.

Forebrain arterioles were analyzed histochemically to determine the effects of an acute administration of ethanol on key enzymes of aerobic and anaerobic metabolism as well as on the hexose monophosphate shunt in rats. The enzymes were glucose 6-phosphate dehydrogenase, cytochrome oxidase, lactate dehydrogenase, beta-hydroxybutyrate dehydrogenase, and isocitrate dehydrogenase. All enzymes were quantified under two conditions: 1 h and 2 days after ethanol administration.

Raman spectroscopic study of left-handed Z-RNA.

The solvent conditions that induce the formation of a left-handed Z form of poly[r(G-C)] have been extended to include 6.5 M NaBr at 35 degrees C and 3.8 M MgCl2 at room temperature.

Stabilization of Z-RNA by chemical bromination and its recognition by anti-Z-DNA antibodies.

Limited chemical bromination of poly[r(C-G)] (32% br8G, 26% br5C) results in partial modification of guanine C8 and cytosine C5, producing a mixture of A- and Z-RNA forms. The Z conformation in the brominated polynucleotide is stabilized at much lower ionic strength than in the unmodified polynucleotide. More extensive bromination of poly[r(C-G)] (greater than 49% br8G, 43% br5C) results in stabilization of a form of RNA having a Z-DNA-like (ZD) CD spectrum in low-salt, pH 7.

Low doses of L-tryptophan are lethal in rats with adrenal insufficiency.

Adrenalectomy decreased the LD50 value for L-tryptophan from greater than 1000 mg/kg in normal rats to 11.6 mg/kg. The LD50 in adrenalectomized rats was restored to normal by corticosterone replacement therapy.

Chronic cocaine administration decreases dopamine synthesis rate and increases [3H] spiroperidol binding in rat brain.

Chronic administration of cocaine HCl (10 mg/kg, IP, every 12 hours for 10 consecutive days) resulted in a significantly decreased rate of accumulation of 3,4-dihydroxyphenylalanine following decarboxylase inhibition (-27 to -33%) and of homovanillic acid following probenecid treatment (-25 to -34%) in rat striatum, limbic forebrain and midbrain. In addition, the Bmax for [3H]-spiroperidol receptor binding was significantly increased (+24 to +36%) in these brain regions following chronic cocaine administration. These changes were observed 60 days following termination of the chronic cocaine treatment regimen.

Chronic cocaine administration depletes tyrosine hydroxylase immunoreactivity in the meso-limbic dopamine system in rat brain: quantitative light microscopic studies.

Chronic administration of cocaine (10 mg/kg, IP, every 12 hours for 10 consecutive days) produced a large decrease in tyrosine hydroxylase staining axons and terminal boutons in the frontal cortex and nucleus accumbens in rats. This treatment also produced a depletion of tyrosine hydroxylase immunoreactivity in the ventral tegmental area of the midbrain when examined 60 days following the final cocaine injection. These effects were quantitated using a Leitz Data Acquisition and Display System.

Dopamine neuron transplants: electrophysiological unit activity of intrastriatal nigral grafts in freely moving cats.

Fetal transplants of substantia nigra dopamine (DA)-containing neurons into the caudate nucleus in cats produced functional synaptic connections, as measured by behavioral analysis. Electrophysiological activity of single units from the intrastriatal nigral grafts revealed that these neurons displayed some of the characteristic electrophysiological parameters of DA neurons, i.e.

Recording of mouse ventral tegmental area dopamine-containing neurons.

We examined the electrophysiologic and pharmacologic properties of dopamine-containing ventral tegmental area neurons in the mouse using extracellular single-unit recording techniques in both chloral hydrate-anesthetized mice and in vitro mouse midbrain slices. In vivo the ventral tegmental area neurons had long-duration action potentials (2 to 5 ms) and discharged at 1 to 9 spikes/s with either a decremental burst pattern or a regular pattern. Systemic administration of the dopamine agonist, apomorphine, decreased their firing rate, and the dopamine receptor blocker, haloperidol, reversed this effect.

Tyrosine hydroxylase immunochemistry and quantitative light microscopic studies of the mesolimbic dopamine system in rat brain: effects of chronic methamphetamine administration.

Long-term treatment of rats with methamphetamine (20 mg/kg, IP, every 12 hours for 10 days) resulted in a large decrease in tyrosine hydroxylase staining axons and terminal boutons in the nucleus accumbens and frontal cortex, as well as the ventral tegmental area of the midbrain, when examined 60 days following termination of the drug treatment regimen. Quantitative analysis showed a 71 and 78% decrease in tyrosine hydroxylase staining processes in the nucleus accumbens and frontal cortex, respectively, and a 90% decrease in tyrosine hydroxylase positive material in the ventral tegmental area. Thus, tyrosine hydroxylase enzyme in both the cell bodies of the midbrain ventral tegmental area as well as in the nerve terminals in post-synaptic target regions of the forebrain is depleted by chronic methamphetamine administration.

A comparison of the electrophysiological and pharmacological properties of serotonin-containing neurons in the nucleus raphe dorsalis, raphe medianus and raphe pallidus recorded from mouse brain slices in vitro: role of autoreceptors.

The potential role of autoreceptors in regulating the activity of serotonin-containing nucleus raphe dorsalis (RD), raphe medianus (RM) and raphe pallidus (RPA) neurons was examined by recording the activity of these neurons under a variety of conditions both in vivo and in vitro. Raphe neurons recorded in vivo displayed the characteristic slow, rhythmic discharge pattern previously described for rat and cat raphe cells. The activity of these neurons was suppressed in a dose-dependent manner by tryptophan, LSD and chlorimipramine administered intravenously.

Phencyclidine suppresses the activity of midbrain dopamine-containing neurons recorded from mouse brain slices in vitro.

Phencyclidine produced a dose-dependent decrease in the activity of dopamine-containing neurons in the substantia nigra and ventral tegmental area recorded from mouse brain slices in vitro. The suppression of dopamine neuronal activity by phencyclidine was blocked by pretreatment of the animals with alpha-methyl-para-tyrosine or haloperidol. These data are in contrast with previous studies which reported that the activity of many midbrain dopamine neurons is increased by phencyclidine, while others are decreased and yet others showed no change.

Acute administration of chloral hydrate depletes cardiac enzymes in the rat.

The arterioles of the left cardiac ventricle were analyzed histochemically to determine the effects of an acute administration of chloral hydrate on key enzymes of aerobic and anaerobic metabolism, as well as the hexosemonophosphate shunt in rats. Significant changes were noted in three of the 5 enzymes examined. Our data suggest that nontoxic levels of chloral hydrate can cause impaired coronary metabolism.

Halothane anesthesia alters cerebral enzymes: a histochemical study in the rat.

Cerebral forebrain arterioles and neuropil were analyzed histochemically to determine the effects of halothane anesthesia on key enzymes of aerobic and anaerobic metabolism, as well as the hexose monophosphate shunt in rats. Significant changes were noted in all five enzymes examined in arterioles, while no changes were observed in the two enzymes involved in aerobic metabolism in the neuropil. Our data suggest that surgical anesthetic levels of halothane can impair forebrain metabolism and lead to altered electrophysiological responses.

Halothane depletes cardiac microvasculature enzymes in the rat.

Left ventricular arterioles from Sprague-Dawley rats were analyzed histochemically to determine the effects of halothane administration on key enzymes of aerobic and anaerobic metabolism, as well as on key enzymes of the hexose monophosphate shunt. Significant decreases occurred in cytochrome oxidase (-42%) and beta-hydroxybutyrate dehydrogenase (-57%). No significant changes were observed in isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, or lactate dehydrogenase.

Chloral hydrate anesthesia alters cerebral enzymes in the rat. A histochemical study.

Cerebral forebrain arterioles and neuropil were analyzed histochemically to determine the effects of chloral hydrate anesthesia on key enzymes of aerobic and anaerobic metabolism, as well as the hexose monophosphate shunt in rats. Significant decreases were observed in cytochrome oxidase, and beta-hydroxybutyrate dehydrogenase in arterioles, while glucose-6-phosphate dehydrogenase and isocitric dehydrogenase showed a significant increase and lactate dehydrogenase showed no significant change. In the neuropil, cytochrome oxidase, isocitrate dehydrogenase and glucose-6-phosphate dehydrogenase showed significant increases following chloral hydrate administration, while beta-hydroxybutyrate dehydrogenase and lactate dehydrogenase showed no significant changes.

Cocaine: long-term administration depletes cardiac enzymes in the rat.

Arterioles and myocytes of the cardiac ventricle were examined histochemically to determine their metabolic profiles in normal rats and in rats treated either acutely or chronically with cocaine. Following long-term, but not acute, cocaine administration, enzymes involved in both aerobic and anaerobic metabolism as well as in hexosemonophosphate shunt were greatly decreased. These data suggest that long-term usage of cocaine leads to severely impaired coronary metabolism.

Mesencephalic arteriolar and neuronal metabolic profiles from fresh and in vitro incubated tissue sections in the mouse: a histochemical approach.

Neuronal perikarya and arterioles of slices of mouse midbrain were examined histochemically to determine their metabolic profiles. No differences in reactivities of key metabolic enzymes were observed between fresh 400-micron tissue sections and sections undergoing in vitro incubation for 4 h at 35 degrees C. Both neurons and arterioles appear capable of aerobic and anaerobic metabolism, while fatty acid utilization is limited.

Chronic cocaine administration depletes tyrosine hydroxylase immunoreactivity in the rat brain nigral striatal system: quantitative light microscopic studies.

Chronic administration of cocaine (10 mg/kg, i.p., every 12 h for 10 consecutive days) produced a large decrease in tyrosine hydroxylase-staining axons and terminal boutons in the caudate nucleus in rats when examined 60 days after the final cocaine injection.