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PubMed1995

Pharmacological induction and modulation of stridulation in two species of acridid grasshoppers

The influence of neurotransmitters and neuroactive substances on stridulatory behaviour was analysed in two species of acridid grasshoppers (Omocestus viridulus and Chorthippus mollis). Acetylcholine, octopamine, gamma-aminobutyric acid and glutamate were applied by pressure injection (0.5­1.0 nl, 10(-3) mol l-1) into the protocerebrum. All except octopamine were also applied to the metathoracic ganglion by pressure injection or superfusion (1 ml). Injection of acetylcholine into the medial dorsal neuropile of the protocerebrum elicited continuous long-lasting species-specific stridulation in both acridid species. All other substances tested had no effect when injected into the brain. Injection of acetylcholine into the medial dorsal neuropile of the metathoracic ganglion enhanced the amplitude of the stridulatory leg movements elicited by electrical brain stimulation. It did not alter the repetition rate or coordination of the movements in O. viridulus; but it decreased the length of stridulatory cycles in C. mollis. Injection of gamma-aminobutyric acid into the medial dorsal metathoracic neuropile in both species suppressed the stridulatory leg movements ipsilateral to the injection site but did not alter those on the contralateral side. Superfusion of the metathoracic ganglion with gamma-aminobutyric acid suppressed the movements of both hindlegs. Pressure injection of glutamate into the metathoracic ganglion had no effect on the stridulatory leg movements, but superfusion enhanced the stridulatory movements.

Journal Article↗
PubMed1998

Locust dorsal unpaired median (DUM) neurones directly innervate and modulate hindleg proprioceptors

A subgroup of the large efferent octopaminergic dorsal unpaired median (DUM) neurones of the third thoracic ganglion, the DUM3,4,5 neurones, directly innervates the tendons of certain proprioceptors of the locust hindleg, the so-called strand receptors. The terminals of the DUM neurones occur in regions of the strands that also contain the dendrites of the mechanoreceptive sensory cells. Both stimulation of the DUM3,4,5 neurones and bath application of octopamine change the responses of strand receptor units to mechanical stimulation. In both situations, most single strand receptor units show an increased response to mechanical stimulation. Some units, however, decrease their sensitivity to mechanical stimulation in response to octopamine application or DUM neurone stimulation.

Journal Article↗
PubMed2000

Inhibition of cytochrome P450c11 by biogenic amines and an aziridine precursor, 2-(4-acetoxyphenyl)-2-chloro-N-methyl-ethylammonium chloride.

The interaction of several biogenic amines and Compound A (2-(4-acetoxyphenyl)-2-chloro- N-methyl-ethylammonium chloride), an analogue of the active substance in a HPLC fraction isolated from the shrub, Salsola tuberculatiformis Botsch., with cytochrome P450c11 was investigated. Noradrenaline, octopamine and Compound A inhibited the type I DOC induced difference spectrum of P450c11 and elicited a type II difference spectrum when added alone. The Ks-values for noradrenaline, octopamine, and Compound A were 0.8 mM, 0.16 mM and 0.36 mM, respectively. Dopamine, adrenaline and synephrine did not interact with, or inhibit, P450c11. Further investigation of Compound A indicated that it is a mixed inhibitor of sheep P450c11 with a stronger competitive (Kic = 106-110 microM) than uncompetitive (Kiu = 667-737 microM) element, and that it inhibits the conversion of deoxycorticosterone to corticosterone by human 11beta-hydroxylase and aldosterone synthase with EC50 values of 97 microM and 190 microM, respectively, in fetal calf serum.

Acetates↗
PubMed1987

The in situ kinetics of dopamine beta-hydroxylase in bovine adrenomedullary chromaffin cells. Intravesicular compartmentation reduces apparent affinity for the cofactor ascorbate.

The Km of dopamine beta-hydroxylase for its cofactor, ascorbic acid, was determined in situ in primary cultures of bovine adrenomedullary chromaffin cells and in isolated chromaffin vesicles. A range of intravesicular ascorbate concentrations in chromaffin cell cultures (1.1-31.2 mM) was achieved by varying the number and concentration of ascorbate additions to the culture media. The rate of octopamine synthesis from tyramine displayed a Michaelis-Menten relationship with respect to ascorbate concentration and an apparent Km of dopamine beta-hydroxylase for ascorbate of 15.0 +/- 2.0 mM was determined. In isolated chromaffin vesicles, with an initial intravesicular ascorbate concentration of approximately 10 mM, ascorbate consumption during beta-hydroxylation occurred as a first order process. This indicated that dopamine beta-hydroxylase was not saturated at this initial ascorbate concentration. When isolated chromaffin vesicles were prepared with different intravesicular ascorbate concentrations, the rate of octopamine synthesis displayed a Michaelis-Menten relationship with respect to ascorbate with an apparent Km of 17.0 +/- 5.0 mM. Ascorbate consumption also occurred as a first order process in ascorbate-loaded chromaffin-vesicle ghosts which had initial ascorbate concentrations of approximately 30 mM but which were depleted of other small molecules such as catecholamines. These results indicate that the in situ Km of dopamine beta-hydroxylase for ascorbate (approximately 15 mM) is 25-fold higher than it is for the purified or partially purified enzyme assayed under optimal conditions in vitro (0.6 mM). The factor(s) which decreases the enzyme affinity for ascorbate, relative to in vitro, resides in the chromaffin vesicle interior and is also retained in chromaffin-vesicle ghosts. The mechanism of this effect remains to be determined. The Km value determined in these experiments is close to the estimated intravesicular ascorbate concentration of bovine chromaffin granules in vivo (4), suggesting that the availability of ascorbate could become a factor in regulating the rate of dopamine beta-hydroxylation.

Adrenal Medulla↗
PubMed1978

Mesentericocaval shunt with the internal jugular vein.

Seventy-nine mesocaval shunts using the internal jugular vein and 54 side-to-side portocaval shunts have been performed during the past six years. Patients were evaluated from the stand-point of protection from recurrent bleeding, patency of the shunt, encephalopathy, rehabilitation and long term survival. All of the patients underwent follow-up observation. In a selected group of patients, postoperative angiographic control was performed, and serum levels of octopamine were examined. In the mesentericocaval group, patency of the shunt was demonstrated in 82 per cent, the incidence of encephalopathy was 35 per cent and the long term survival rate, as computed by the actuarial method, was 65 per cent. In the portocaval group, the incidence of encephalopathy was 54 per cent and the survival rate, 38 per cent. There was no correlation between octopamine serum levels and encephalopathy. Persistent perfusion of the liver was documented in 95 per cent of the patents controlled by arteriography in the mesentericocaval group with patent shunts. The mesentericocaval shunt seems to be an effective technique in terms of incidence of encephalopathy and survival rate, but a randomized study will be necessary to prove that this technique is more effective than the standard portocaval shunt.

Brain Diseases↗
PubMed1981

Comparative histochemistry as a springboard for the discovery of biogenic amines and active peptides in molluscan tissues and amphibian skin.

Histochemistry has been the springboard for the identification in molluscan tissues (hypobranchial body and salivary glands) and amphibian skin of a number of biogenic amines, choline esters and active peptides. Among the biogenic amines 5-HT and related indolealkylamines, octopamine, tyramine and several histamines are to be listed; among the choline esters murexine, dihydromurexine, senecioylcholine and acryloylcholine; among the peptides an array of compounds belonging to at least ten different peptide families. 5-HT, octopamine, tyramine and histamine are present, together with representatives of some peptide families in the posterior salivary glands of octopods, the hypobranchial body of prosobranchiate molluscs and the amphibian skin. This points to the possible occurrence in the above structures of cells belonging to the Pearse's APUD series, intended in its broadest sense. Immunocytochemical studies and even ultrastructural studies on amine and peptide storing cells in molluscan tissues and amphibian skin are virtually lacking. This is certainly a gap that deserves to be filled, considering that these studies may help in elucidating problems of general relevance in invertebrates and vertebrates.

Amphibian Proteins↗
PubMed1981

Death after portal decompressive surgery. Physiologic state, metabolic adequacy, and the sequence of development of the physiologic determinants of survival.

Detailed serial cardiovascular and respiratory physiologic studies were carried out in 80 patients with cirrhotic liver disease, including 45 cirrhotic patients who underwent portal decompressive surgery on an urgent or elective basis. In surgical cases, death could be predicted from the first postoperative day's pattern of response. Predictors of death were an increase in percent of pulmonary shunt due to a redistribution of the increased pulmonary blood flow, and a disproportionate fall in vascular tone, which permits an increased cardiac ejection fraction even when significant myocardial depression occurs. The etiology of the vascular tone defect seems related to the rise in levels of the false neurotransmitter octopamine, which are shown to increase as oxygen consumption falls in the patho-physiologic hyperdynamic B state, presumably due to a block in the oxidative metabolism of aromatic amino acids.

Esophageal and Gastric Varices↗
PubMed1999

Colocalisation of taurine- with transmitter-immunoreactivities in the nervous system of the migratory locust.

The expression of taurine immunoreactivity (TAU-IR) by neurones immunoreactive for octopamine (OA-IR), gamma-aminobutyric acid (GABA-IR), and the C-terminal peptide sequence arginine-phenylalanine (RFamide-IR) was investigated in the migratory locust (Locusta migratoria). TAU-IR is colocalised with OA-IR in the dorsal unpaired median neurones, which are efferent neuroparacrine cells. TAU-IR is not, however, expressed by OA-IR interneurones in the thoracic ganglia and brain. The only other TAU-IR somata found with peripheral axons are the medial neurosecretory cells in abdominal ganglia that project to the neurohaemal organs. These cells exhibit RFamide-IR. The majority of TAU-IR somata in the thoracic abdominal nervous system exhibit GABA-IR. These cells correspond to populations of identified local and intersegmentally projecting inhibitory interneurones. TAU-IR is not, however, exhibited by the well-known GABAergic common inhibitor neurones, which have peripherally projecting axons. This differential distribution of TAU-IR in basically two, functionally different, neuronal subsets (efferent neurosecretory and neuroparacrine cells, inhibitory interneurones) conforms with the concept of taurine acing as a depressive agent to limit excitation during stressful conditions.

Animals↗
PubMedDate not supplied

Distribution and functional anatomy of amine-containing neurons in decapod crustaceans.

One of the lessons learned from studying the nervous systems of phylogenetically distant species is that many features are conserved. Indeed, aminergic neurons in invertebrate and vertebrate systems share a multitude of common characteristics. In this review, the varied roles of serotonin, octopamine, dopamine, and histamine in decapod crustaceans are considered, and the distributions of the amine-containing cells are described. The anatomy of these systems reinforces the idea that amine neurons are involved in widespread modulation and coordination within the nervous system. Many aminergic neurons have long projections, linking multiple regions with a common input, and therefore are anatomically perfected as "gain setters." The developmental patterns of appearance of each amine in the crustacean nervous system are described and compared. The developmental picture suggests that transmitter acquisition is distinctive for each amine, and that the pace of acquisition may be co-regulated with target maturation. The distinctive roles that transmitters play during specific developmental periods may, ultimately, provide important clues to their functional contributions in the mature organism.

Amines↗
PubMed2001

Substituent-dependent, positive and negative modulation of Bombyx mori adenylate cyclase by synthetic octopamine/tyramine analogues.

Octopamine (OCT)/tyramine (TYR) analogues, mainly including p- and beta-substituted phenylethylamines, were prepared as probes for the ligand-binding site(s) of adenylate cyclase-coupled OCT or TYR receptors, and were examined for their effects on cAMP production in the head membranes of Bombyx mori larvae. Small structural changes in OCT and TYR proved to lead to three types of OCT/TYR analogues: (1) compounds that increase the cAMP level by themselves and also depress OCT-stimulated cAMP production, (2) compounds that do not stimulate cAMP production by themselves but inhibit OCT-stimulated cAMP production, and (3) compounds that are not active in either the stimulation of cAMP production or the inhibition of OCT-stimulated cAMP production. Tyramine, which belongs to the second group, also inhibited the basal level of cAMP production at high concentrations. The data indicate that two biogenic amine systems that positively and negatively regulate the level of the second messenger cAMP are present in the head part of B. mori larvae. This finding points to the necessity of separately evaluating the positive and negative regulatory effects in order to quantitatively understand the structure-activity relationships of OCT receptor ligands. Arch.

Adenylyl Cyclases↗
PubMed2001

Molecular and pharmacological properties of insect biogenic amine receptors: lessons from Drosophila melanogaster and Apis mellifera.

In the central nervous system (CNS) of both vertebrates and invertebrates, biogenic amines are important neuroactive molecules. Physiologically, they can act as neurotransmitters, neuromodulators, or neurohormones. Biogenic amines control and regulate various vital functions including circadian rhythms, endocrine secretion, cardiovascular control, emotions, as well as learning and memory. In insects, amines like dopamine, tyramine, octopamine, serotonin, and histamine exert their effects by binding to specific membrane proteins that primarily belong to the superfamily of G protein-coupled receptors. Especially in Drosophila melanogaster and Apis mellifera considerable progress has been achieved during the last few years towards the understanding of the functional role of these receptors and their intracellular signaling systems. In this review, the present knowledge on the biochemical, molecular, and pharmacological properties of biogenic amine receptors from Drosophila and Apis will be summarized. Arch.

Animals↗
PubMed1980

Increased excretion of o-hydroxymandelic acid in phenylketonuria.

o-Hydroxymandelic acid has been found in large amounts in the urine of patients with phenylketonuria by gas chromatography mass spectrometry selected ion monitoring. Using deuterated o-hydroxymandelic acid as an internal standard, five patients were found to excrete 150-340 ng mg-1 creatinine. This may be compared with the excretion of 4-16 ng mg-1 creatine by normal subjects. Neither o-octopamine nor o-synephrine were found in urine under conditions by which 1 ng mg-1 creatinine would have been detected.

Gas Chromatography-Mass Spectrometry↗
PubMed1982

Identification and quantitative determination of m-hydroxyphenylglycol in mammalian urine.

m-Hydroxyphenylglycol (MHPG) has been identified in mammalian urine by gas chromatography mass spectrometry selected ion monitoring. (2H0) MHPG and (2H5) MHPG were synthesized for use as authentic sample and internal standard, respectively. After acid hydrolysis or treatment with sulfatase, the glycol was extracted from urine with ethyl acetate, converted to its tris-pentafluoropropionyl (PFP) derivative and identified by comparison of the retention times and relative intensities of the characteristic ions, m/z 592, m/z 428 and m/z 415, with those from the authentic sample. Using the internal standard the following quantitative results were obtained: 10 normal human adults excreted 7 ng MHPG mg-1 creatinine (range 2-18) as a sulfate conjugate. Ten rats excreted 0.8 micrograms day-1 (range 0.5-1.1) of MHPG also in the conjugated form. Urinary m-hydroxymandelic acid (MHMA) was also measured quantitatively. The ratio MHMA:MHPG was 1:1 in the rat and 6:1 in the human. This indicates that the overall reductive pathway of m-octopamine and m-synephrine metabolism is more important in the rat than in the human. o-Hydroxyphenylglycol (OHPG) and the three isomeric monomethoxy phenylglycols could not be detected in human or rat urine by these techniques.

2-Hydroxyphenethylamine↗
PubMed2004

Morphology and molecular organization of the adult neuromuscular junction of Drosophila.

While the larval neuromuscular junction (NMJ) of Drosophila has emerged as a model system to study synaptic function and development, little attention has been given to the study of the adult NMJ. Here we report an immunocytochemical and morphological characterization of an adult NMJ preparation of the prothorax. All muscles examined were innervated by small, uniform type II terminals (0.5-1.5 microm), a subset of which contained octopamine. Terminals classified as type I varied in their morphology across different muscles, ranging from strings or clusters of boutons (0.8-5.5 microm) to an elongate terminal (80-100 microm long) with few branches and contiguous swellings (3-15 microm) along its length. Analysis of the molecular composition of the NMJs during the first 5 days after eclosion revealed four major findings: 1) type I boutons increase in size during early adulthood; 2) Fasciclin II-immunoreactivity is not detectable at type I terminals, while DLG-immunoreactivity is observed at the synapse; 3) a Shaker-GFP fusion protein that localizes to all type I boutons in the larva is differentially localized at adult prothoracic NMJs; and 4) while all type I terminals contain glutamate, the glutamate receptor subunits, DGluRIIA and DGluRIIB, are expressed and clustered in only a subset of muscles. These findings suggest that maturation of the adult NMJ occurs during early adulthood and that muscle-specific properties may play a role in organizing synaptic components in the adult. Furthermore, these results demonstrate that there are major differences in the molecular organization of the adult and larval NMJs.

Aging↗
PubMed1994

Agonist-specific coupling of a cloned Drosophila octopamine/tyramine receptor to multiple second messenger systems.

A cloned seven transmembrane-spanning Drosophila octopamine/tyramine receptor, permanently expressed in a Chinese hamster ovary cell line, both inhibits adenylate cyclase activity and leads to the elevation of intracellular Ca2+ levels by separate G-protein-coupled pathways. Agonists of this receptor (octopamine and tyramine), differing by only a single hydroxyl group in their side chain, may be capable of differentially coupling it to different second messenger systems. Thus, a single receptor may have a different pharmacological profile depending on which second messenger system is used to assay its efficacy.

Animals↗
PubMed1975

Effect of pharmacological agents on human keratinocyte mitosis in vitro. II. Inhibition by catecholamines.

Catecholamines produce mitotic inhibition in primary cell cultures of human keratinocytes probably via a block in the G2 part of the cell cycle. Epinephrine produced significant mitotic inhibition (49%) at a concentration as low as 4.5 X 10(-10) M, while its analog, isoproterenol, produced 47% inhibition at 1 X 10(-10) M. Norepinephrine elicited a 49% inhibitory response at 1 X 10(-8) M. One other catecholamine, dopamine, caused a 53% decrease in mitosis at 1 X 10(-6) M. Other structurally related amines to exhibit mitotic inhibition were phenylephrine, 58% at 1 X 10(-7) M; octopamine, 47% at 1 X 10(-5) M; and tyramine, 52% at 1 X 10(-4) M. Serotonin showed no mitotic inhibition at 1 X 10(-4) M. Various alpha and beta adrenergic blocking agents were added to the cell system. The alpha blocking agent, phentolamine, had no effect on mitosis. When added in conjunction with epinephrine or norepinephrine, no reduction of the catecholamine-induced mitotic inhibition was observed. The beta blocking agent, propranolol, by itself showed slight mitotic inhibition at 1 X 10(-6) M. When added along with epinephrine or noreinephrine, propranolol reduced the catecholamine-induced mitotic inhibition approximately 65%. In addition, propranolol blocked mitotic inhibition caused by phenylephrine, an alpha adrenergic agent. However, another beta blocking agent, dichloroisoproterenol, showed strong mitotic inhibition (53%) when added to the cultures at a concentration of 1 X 10(-8) M. The effect was reduced to zero in the presence of propranolol. These data suggest that while beta receptors may be involved in the catecholamine-induced mitotic inhibition of human keratinocytes in vitro, the nature of the receptor-molecule interaction may be complex.

Catecholamines↗
PubMed2006

Oviduct contraction in Drosophila is modulated by a neural network that is both, octopaminergic and glutamatergic.

Fertility is a highly complex and regulated phenomenon essential for the survival of any species. To identify Drosophila fertility-specific neural networks, we used a GAL4/UAS enhancer trap genetic screen that selectively inactivates groups of neurons. We identified a GAL4 line (bwktqs) that has a female sterile phenotype only when it expresses the tetanus toxin light chain (TeTxLC). These flies lack oviduct contraction, lay almost no eggs, sperm accumulate in the oviducts, and fewer than normal are seen in the storage organs. In insects, two neuroactive substances are important for oviduct contraction: octopamine (OA), a monoamine that inhibits oviduct contraction, and glutamate (Glu), a neurotransmitter that induces contraction. It is known that octopaminergic neurons of the thoracic abdominal ganglion (TAG) modulate oviduct contraction, however, the glutamatergic neurons that innervate the oviduct have not been identified yet and the interaction between these two neuroactive substances is not well understood. Immunostaining experiments revealed that the bwktqs line trapped an octopaminergic neural network that innervates the genital tract. We show that wt like oviduct contraction in TeTxLC-inactivated flies can only be rescued by simultaneous application of Glu and OA suggesting that the abdominal bwktqs neurons are both octopaminergic and glutamatergic, the use of an agonist and an antagonist for Glu receptors as well as their direct visualization confirmed its participation in this phenomenon. Our work provides the first evidence that adult abdominal type II visceral innervations co-express Glu and OA and allows us to re-evaluate the previous model of neuronal network controlling insect oviduct contraction.

Animals↗
PubMed1980

Drug-induced changes in catecholaminergic cells of the fish retina.

The changes in fluorescence intensity and number of visible catecholaminergic cells (CA-cells), as revealed by means of a histofluorescence technique, were used as indicators of the effects of various pharmacological agents upon CA-cells in the retina of fishes (Cyprinus carpio and Eugerres plumieri). The study includes in vivo and in vitro experiments. In the in vivo experiments, intravitreal injection, two or three hours before eye enucleation, of 10 microgram L-DOPA, dopamine, or noradrenaline accentuated CA-cell fluorescence and increased the number of visible cells, whereas 10 microgram of tyramine, octopamine, synephrine, or adrenaline reduced the endogenous fluorescence. Intramuscular injection of reserpine (3 mg/kg) abolished CA-cell fluorescence. In the in vitro experiments, pieces of isolated retinas were incubated for three or 30 minutes in media containing different drugs. Only minor changes in fluorescence were detected after three minutes of incubation, but after 30 minutes, dopamine (20 microM) markedly enhanced CA-cell fluorescence. Carbachol (20 mM), acetylcholine (10 mM) plus BW-anticholinesterase (1 mM) or substance P(1.6 x 10(-2) mM), all reduced CA-cell fluorescence. Kainic acid (20 mM) abolished fluorescence from CA-cell somata, while fluorescent fiber networks remain unchanged. L-aspartate (5 mM) and GABA (10 mM) in the incubation medium did not influence fluorescence intensity. The results are relevant to, and consistent with, electrophysiological observations of dopamine-mediated spatial effects on horizontal cell potentials.

Acetylcholine↗