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PubMed1977

The measurement of 3-o-methyldopamine in urine and plasma by a rapid and specific radioimmunoassay.

Antiserum against 3-O-methyldopamine (MD) was produced in rabbits immunized with MD hapten conjugated to hemocyanin. The antiserum was used to develop a radioimmunoassay (RIA) for MD. As little as 0.5 ng of MD in 0.1 ml can be detected. The major catecholamines and the phenolic aromatic amines (dopamine, norepinephrine, epinephrine, octopamine, and tyramine) and their metabolites (normetanephrine, metanephrine, homovanillic acid and 4-hydroxy-3-methxymandelic acid) did not bind significantly to the antibody. The RIA of MD was used to assay the endogenous level of MD in urine and plasma of hospitalized children. In children (7 mo to 13 yr), average concentration of MD in plasma was found to be 0.47 +/- 0.11 ng/ml, and in urine 0.15 +/- 0.05 microgram/mg of creatinine (45.0 +/- 16.3 microgram/24 hr). In children with neuroblastoma, there was a 3- to 10-fold increase in urinary excretion and plasma level of 3-O-methyldopamine. In adults, the average urine and plasma levels were found to be 87.4 +/- 3.4 microgram/24 hr and 0.6 +/- 0.2 ng/ml. The diagnostic applicability of the RIA of MD is discussed.

Adolescent↗
PubMed1999

The cat-1 gene of Caenorhabditis elegans encodes a vesicular monoamine transporter required for specific monoamine-dependent behaviors.

We have identified the Caenorhabditis elegans homolog of the mammalian vesicular monoamine transporters (VMATs); it is 47% identical to human VMAT1 and 49% identical to human VMAT2. C. elegans VMAT is associated with synaptic vesicles in approximately 25 neurons, including all of the cells reported to contain dopamine and serotonin, plus a few others. When C. elegans VMAT is expressed in mammalian cells, it has serotonin and dopamine transport activity; norepinephrine, tyramine, octopamine, and histamine also have high affinity for the transporter. The pharmacological profile of C. elegans VMAT is closer to mammalian VMAT2 than VMAT1. The C. elegans VMAT gene is cat-1; cat-1 knock-outs are totally deficient for VMAT immunostaining and for dopamine-mediated sensory behaviors, yet they are viable and grow relatively well. The cat-1 mutant phenotypes can be rescued by C. elegans VMAT constructs and also (at least partially) by human VMAT1 or VMAT2 transgenes. It therefore appears that the function of amine neurotransmitters can be completely dependent on their loading into synaptic vesicles.

Amino Acid Sequence↗
PubMed1999

Distribution and activation of different types of octopaminergic DUM neurons in the locust.

The first part of this study describes the distribution of all different types of octopaminergic, efferent dorsal unpaired median (DUM) neurons in the first two thoracic ganglia by immunocytochemistry, retrograde labeling, and intracellular staining. The prothoracic ganglion contains five different types of 10 DUM neurons. The mesothoracic ganglion has 21 octopaminergic somata in the DUM neuron cluster. Retrograde labeling and intracellular staining show that 19 of these 21 somata belong to five different types of efferent DUM neurons. In both ganglia, the number and the distribution of all types of DUM neurons are completely described. Differences in the distribution of efferent DUM neurons between the thoracic ganglia are discussed as functional segmental specializations. In the second part, we show that, in contrast to previous suggestions, DUM neurons are not recruited as a homogeneous population mediating general arousal but differentially, thus forming subpopulations of specific types. The existence or the absence of commonly occurring postsynaptic potentials in paired recordings clearly shows that only specific types of DUM neurons are targeted by the same presynaptic pathways. Within the thoracic ganglia, different subpopulations of DUM neurons can be distinguished by their different local inputs. Furthermore, only specific subpopulations of DUM neurons receive common intersegmental drive and inputs from the subesophageal ganglion. As a result of all our recordings, we propose a scheme for the differential activation of efferent DUM neurons. This scheme is sufficient to explain DUM neuron activity during principal motor programs.

Animals↗
PubMedDate not supplied

Direct chiral resolution of phenylalkylamines using a crown ether chiral stationary phase.

A direct, isocratic high-performance liquid chromatographic method is described for the enantiomeric resolution of a number of phenylalkylamines, namely, racemic cathinone, amphetamine, norephedrine, and norphenylephrine, without sample derivatization. The separations were achieved on an S-18-crown-6-ether chiral stationary phase known as CR(+). The chromatographic parameters alpha (separation factor) and Rs (resolution factor) lay within a narrow range for all compounds used in this study except for cathinone, which resulted in high alpha and Rs values. The recognition mechanism for this column involves the interaction of the crown structure with a charged primary ammonium ion. The stereochemical structures of the compounds in this study contribute to the results obtained for the chromatographic parameters, especially in cathinone's case. This paper will discuss the recognition mechanism contributing to the high alpha and Rs, values obtained for cathinone.

Alkaloids↗
PubMed2001

Dopamine-synthesizing neurons include the putative H-cell homologue in the moth Manduca sexta.

The catecholamine dopamine (DA) plays a fundamental role in the regulation of behavior and neurodevelopment across animal species. Uncovering the embryonic origins of neurons that express DA opens a path for a deeper understanding of how DA expression is regulated and, in turn, how DA regulates the activities of the nervous system. In a well-established insect model, Manduca sexta, we identified the putative homologue of the embryonic grasshopper "H-cell" using intracellular techniques, laser scanning confocal microscopy, and immunohistochemistry. In both species, this neuron possesses four axons and has central projections resembling the letter H. The H-cell in grasshoppers is known to be derived from the midline precursor 3 cell (MP3) and to pioneer the pathways of the longitudinal connectives; in Drosophila, the H-cell is also known to be derived from MP3. In the current study, we demonstrate that the Manduca H-cell is immunoreactive to antibodies raised against DA and its rate-limiting synthetic enzyme, tyrosine hydroxylase (TH). In larvae and adults, one DA/TH-immunoreactive (-ir) H-cell per ganglion is present. In embryos, individual ganglia contain a single midline TH-ir cell body positioned along side its putative sibling. Such observations are consistent with the known secondary transformation (in grasshoppers) of only one of the two MP3 progeny during early development. Although a hallmark feature of invertebrate neurons is the fairly stereotypical position of neuronal somata, we found that the H-cell somata can "flip-flop" by 180 degrees between an anterior and posterior position. This variability appears to be random and is not restricted to any particular ganglion. Curiously, what is segment-specific is the absence of the DA/TH-ir H-cell in the metathoracic (T3) ganglion as well as the unique structure of the H-cell in the subesophageal ganglion. Because this is the first immunohistochemical study of DA neurons in Manduca, we have provided the distribution pattern and morphologies of dopaminergic neurons, in addition to the H-cells, within the ventral nerve cord during development.

Animals↗
PubMed2004

The effect of mutations altering biogenic amine metabolism in Drosophila on viability and the response to environmental stresses.

Dopamine (DA) content, tyrosine decarboxylase (TDC) activity and survival were studied under normal and environmental stress conditions in the ste and e strains carrying ebony mutation increasing DA level and the octopamineless strain Tbetah(nM18) of Drosophila melanogaster. Wild-type strains Canton S and Oregon R, and strain p845 from which Tbetah(nM18) strain was derived were used as controls. Sexual dimorphism of TDC activity, DA content, and survival in flies of all D. melanogaster strains under study was found. Tbetah(nM18) mutation sharply reduced TDC activity in females, while ebony had no such effect. DA content and survival under heat stress in Tbetah(nM18) flies did not differ from those in the wild type. ste and e flies had drastically increased DA content under normal conditions, dramatically decreased survival under heat stress, but increased survival under starvation. DA content and survival under heat stress were also studied in the reciprocal hybrids (males) F(1) of the cross D. virilis strains 101 (wild type) and 147 with X-linked mutation, which significantly increases DA content. 147x101 males had a considerably higher DA content and lower survival than 101x147 ones. Individuals of all D. melanogaster strains under study developed the stress reaction, as judged by changes in TDC activity and DA levels. The role of biogenic amines in the stress reaction development and adaptation to environmental stresses in Drosophila is discussed. Arch. Insect Biochem. Physiol. 55:55-67, 2004.

Adaptation, Physiological↗
PubMed1995

Corpora allata of the larval tobacco hornworm contain a calcium/calmodulin-sensitive adenylyl cyclase.

An assay was developed with which to study basic characteristics of an adenylyl cyclase in the corpora allata (CA) of the tobacco hornworm, Manduca sexta. The assay used glands collected and frozen at -80 degrees C, to circumvent the problem of tissue availability. With this protocol for storage of tissue, less than 25% of the enzyme activity in fresh tissue was lost. Substances such as sodium fluoride (NaF) and Gpp(NH)p (a non-hydrolyzable GTP analog), which typically stimulate the adenylyl cyclases in other insect tissues, increased enzyme activity several-fold. There was a progressive decrease in the capacity of the CA adenylyl cyclase to be stimulated by NaF during the fifth stadium, suggesting a possible developmental change in the capacity of the associated G protein to be stimulated by NaF. The calcium/calmodulin (CaM) dependence of adenylyl cyclase activity was also investigated. The results demonstrated that addition of up to 10(-4) M calcium to assays of enzyme activity in whole gland homogenates of both larval (day 0) and prepupal (day 6) CA resulted in only a slight increase in the activity of the enzyme over basal rates in the presence of the calcium chelator EGTA. However, addition of as little as 5 microM CaM in the presence of 10(-4) to 10(-3) M calcium increased adenylyl cyclase activity three-to five-fold. A similar stimulation was obtained with washed membrane preparations of day 0 and day 6 glands, but required a substantially higher concentration of CaM. Results demonstrated that the CA possess a calcium/CaM-dependent adenylyl cyclase from day 0 through day 6.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed2004

The pheromone production of female Plodia interpunctella is inhibited by tyraminergic antagonists.

Several compounds were found to suppress the calling behavior and in vitro pheromone biosynthesis of the Indian meal moth, Plodia interpunctella. The compounds were screened by means of a calling-behavior bioassay with female P. interpunctella. Five derivatives with activities in the nanomolar range were identified, in order of decreasing pheromonostatic activity: 4-hydroxybenzaldehyde semicarbazone (42) > 5-(4-methoxyphenyl)-1,3-oxazole (38) > 5-[4-(tert-butyl)phenyl]-1,3-oxazole (40) > 5-(3-methoxyphenyl)-1,3-oxazole (35) > 5-(4-cyanophenyl)-1,3-oxazole (36). These compounds also showed in vitro inhibitory activity in intracellular de novo pheromone biosynthesis, as determined with isolated pheromone-gland preparations that incorporated [1-(14)C]sodium acetate in the presence of the so-called pheromone-biosynthesis-activating neuropeptide (PBAN). The non-additive effect of the inhibitor with antagonist (yohimbine) for the tyramine (TA) receptor suggests that it could be a tyraminergic antagonist. Three-dimensional (3D) computer models were built from a set of compounds. Among the common-featured models generated by the program Catalyst/HipHop, aromatic-ring (AR) and H-bond-acceptor-lipophilic (HBAl) features were considered to be essential for inhibitory activity in the calling behavior and in vitro pheromone biosynthesis. Active compounds, including yohimbine, mapped well onto all the AR and HBAl features of the hypothesis. Less-active compounds were shown to be unable to achieve an energetically favorable conformation, consistent with our 3D common-feature pharmacophore models. The present hypothesis demonstrates that calling behavior and PBAN-stimulated incorporation of radioactivity are inhibited by tyraminergic antagonists.

Animal Communication↗
PubMed2007

A new copper(I)-tetrahydrosalen-catalyzed asymmetric Henry reaction and its extension to the synthesis of (S)-norphenylephrine.

A new chiral hydrogenated salen catalyst has been developed for the asymmetric Henry reaction which produces the expected products in moderate to high yields (up to 98 %) with excellent enantioselectivities (up to 96 % ee). A variety of aromatic, heteroaromatic, enal, and aliphatic aldehydes were found to be suitable substrates in the presence of hydrogenated salen 1 f (10 mol %), (CuOTf)(2)C(7)H(8) (5 mol %), and 4 A molecular sieves. This process is air-tolerant and easily manipulated with readily available reagents, and has been successfully extended to the synthesis of (S)-norphenylephrine in 67 % overall yield, starting from commercially available m-hydroxybenzaldehyde. Based on experimental investigations and MM+ calculations, a possible catalytic cycle including a transition state (8 or A) has been proposed to explain the origin of reactivity and asymmetric inductivity.

Catalysis↗
PubMed2004

Projection patterns of posterior dorsal unpaired median neurons of the locust subesophageal ganglion.

Six neurons in a group of dorsal unpaired median (DUM) neurons with cell bodies in the posterior part-maxillary and labial neuromeres-of the subesophageal ganglion of locusts have two axons each that descend into both the left and the right halves of the ganglia of the ventral nerve cord. None of the neurons has peripheral axons, so they are interneurons. Electrophysiology shows that the axons of at least four neurons project to the terminal abdominal ganglion to which they conduct spikes at a velocity of 0.5-0.6 m. second(-1). In the somata, the spikes have a smaller amplitude and briefer duration at half height than the spikes of thoracic, efferent DUM neurons. Each neuron has bilaterally symmetrical branches within the subesophageal ganglion and in the thoracic ganglia. On the basis of the specific patterns of branches, and the neuropiles, tracts, and commissures in which they occur, three types of neurons (DUM SD 1-3) can be recognized. DUM SD 1 and 3 project to ventral regions of neuropile in the thoracic ganglia in which the efferent DUM neurons of these ganglia have no branches. DUM SD 2 projects to dorsal neuropiles. The projection patterns of these putatively octopaminergic neurons suggest that they could be the source of the octopaminergic modulation of networks underlying sensory processing and motor pattern generation within these ganglia. Within this group of posterior DUM neurons, two additional cells were stained that have axons ascending to the brain.

Animals↗
PubMed2005

Chiral separations on multichannel microfluidic chips.

Chiral separations of FITC-labeled basic drugs on multichannel microfluidic chips with LIF detector were investigated. A preliminary screening procedure for seven neutral CDs was performed under optimized conditions for chiral separations of three FITC-labeled drugs (baclofen, norfenefrine, and tocainide) on a mono-channel microfluidic chip. According to the results of screening, FITC-baclofen and FITC-norfenefrine as well as two chiral selectors including gamma-CD and dimethyl-beta-CD (DM-beta-CD) were selected as models to perform chiral separations on a two-channel chip. FITC-baclofen enantiomers were separated completely by gamma-CD in one channel, while resolution of FITC-norfenefrine enantiomers was achieved by DM-beta-CD in the other channel in the same run. Furthermore, the feasibility of using one chiral selector to separate multiple chiral samples was studied on a four-channel chip. These results show that multichannel chip has a potential for chiral high-throughput screening.

Baclofen↗
PubMed1980

Fine structure of an octopaminergic neuron and its terminals.

The large octopaminergic dorsal unpaired median neuron of the locust that innervates the extensor tibiae muscle, DUMETi, was examined electronmicroscopically. Its soma contains many Golgi complexes apparently making dense-core vesicles similar to those found in peripheral branches and terminals. There are also larger stores of the dense material in the soma, especially near the exit of the principal neurite, that are not in vesicular form. Since the neurons can be penetrated and stimulated by microelectrodes, they form favorable subjects for direct studies of the control of neurosecretion. Preterminal fine branches of the neuron were located in proximal outer bundles of muscle fibers into which they had been traced electrophysiologically. They contain numerous large dense-core vesicles arrayed in rows near microtubules. These fine branches have a thick layer of collagenous connective tissue between the axon and the muscle fiber. Final terminals have varicosities containing many vesicles, lying inside the outer layers of the sarcolemmal complex of muscle fibers. They do not form synaptic structures. Terminals of another DUM neuron, one that innervates the dorsal longitudinal flight muscles (DUMDL), were similar in detail to those of DUMETi. DUMETi swelled about 20-fold in cross-sectional area above a ligature, in a 12-hr period, indicating that there is an extensive centrifugal flow of material in it, and sprouted a branch.

Animals↗