Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Octopamine”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed2004

Thee effect of 5-HTP on the reproductive timer in the male cricket.

The post-copulatory sexually refractory stage in the male cricket Gryllus bimaculatus consists of the two substages: the first refractory stage (RS1, time-variable) between copulation and spermatophore preparation, and the second refractory stage (RS2, time-constant) between spermatophore preparation and the recommencement of courtship. To understand the mechanism of the timer for RS2, subcuticular or intraganglionic injection of biogenic amines (10(-2) mol l(-1)) was performed immediately after spermatophore preparation. RS2 was shortened by octopamine, 5-HT, 5-HTP and NA-5-HT. Among these, 5-HTP was most potent. It shortened RS2 to maximally about 38% of the control. The shortening effect continued for 4.5 h after subcuticular injection even when the hemolymph was washed out with saline at 1 hour after injection. Simultaneous injection of 5-HTP with the inhibitor (NSD-1015) of 5-HT synthesis enzyme nullified the effect of 5-HTP, indicating that the shortening effect was caused by 5-HT synthesized from extrinsic 5-HTP. Injection of the inhibitor (CHX) of protein synthesis had no effect of on RS2. These results suggest that the reproductive timer in the TAG may be controlled by 5-HT or a second messenger mediated by 5-HT.

5-Hydroxytryptophan↗
PubMed1978

Further study on the effect of mersalyl, an organic mercurial, on relaxing response of a molluscan smooth muscle to monoamines.

The effect of mersalyl on the relaxation of catch by various monoamines was studied in the anterior byssal retractor muscle of Mytilus. As has already been reported, mersalyl blocked the relaxing response to indoleamines but not block that to catecholamines. The relaxations in response to catecholamine-related compounds (dopa, octopamine, tyramine, phenylephrine, beta-phenylethylamine and phenylethanolamine) and hexylamine were, however, antagonized more or less effectively with mersalyl. It was suggested that the catecholamine-related compounds and hexylamine can act on relaxing nerve endings to increase neurotransmitter serotonin in the junctional clefts, and mersalyl antagonizes the relaxation in response to these compounds by blocking the serotonin.

Animals↗
PubMedDate not supplied

[Catecholamines in the human diencephalon].

INTRODUCTION: Catecholamines are chemical compounds which play an important role as neurotransmitters in many vital functions of the organism. The paper presents a short survey of their biosynthesis, disintegration andfunctions, with respect to the neuroanatomical location of cell groups which contain these compounds. CATECHOLAMINES IN THE HUMAN HYPOTHALAMUS: Because the authors were most interested in the behavior of catecholamines in the diencephalon, particularly in the hypothalamus, they focussed their attention on cells secreting catecholamines (dopamine, noradrenaline, adrenaline, octopamine). The paper also deals with the connections between cellular structures which emit and receive the neuronal impulses that transport catecholamines as neurotransmitters. These include the following dopaminergic systems: nigrostriatal, tuberohypophysial, retinal, periventricular, periglomerular and dopaminergic systems in mesolimbic, mesocortical and diencephalic regions. The paper also indicates other areas in human brain with adrenaline and noradrenaline secreting cells.

Catecholamines↗
PubMed1982

Regional distribution of noradrenaline and dopamine-beta-hydroxylase in the brain of spontaneously hypertensive rats.

The catecholamine concentration and dopamine-beta-hydroxylase activity were determined in several nuclei of the brain of spontaneously hypertensive rats (SHR) compared with Wistar Kyoto (WKY) controls. Catecholamines were measured by using liquid chromatography coupled with electrochemical detection. The threshold of detection was 5 X 10(-14) mole. Dopamine-beta-hydroxylase (DBH) was assayed by a sensitive radioenzymatic assay using tyramine as the substrate. The limit of detection was 5 pmoles of octopamine per sample. Significantly lower noradrenaline content was observed in 4 week-old SHR in some medullary and hypothalamic areas which are involved in cardiovascular regulation. This abnormally was no longer detectable in 12 week-old rats. The changes in catecholamine levels observed in young rats were not observed during the development of deoxycorticosterone-salt hypertension and therefore probably do not represent a compensatory mechanism tending to limit the progressive rise blood pressure. No significant difference in DBH activity was observed between the young SHR and WKY in any brain region measured. The altered relationship between noradrenaline content and DBH activity observed in young SHR when compared to WKY suggests a change in noradrenergic neurones activity and/or structure which could correspond to a genetically transmitted neurochemical abnormality associated with the initiation of hypertension in the SHR.

Age Factors↗
PubMed2000

Influence of hygienic quality of raw materials on biogenic amine production during ripening and storage of dry fermented sausages.

The effect of the hygienic status of raw materials on biogenic amine production during ripening and storage (at 4 and 15 degrees C) of fermented sausages was studied. Two portions of fresh lean and back fat pork were stored for 5 days at -20 degrees C (treatment A) and at 4 degrees C (treatment B), respectively. Raw materials of treatment A maintained their hygienic quality high and low amine content. Raw materials of treatment B showed from 1 to 3 log (CFU/g) higher microbial counts and a biogenic amine index near 50 mg/kg, indicating poorer hygienic quality. The quality of raw materials influenced the composition and the concentration of biogenic amines produced during the ripening sausages. Sausages of treatment A (A-sausages) showed a large accumulation of tyramine (up to 100 mg/kg dm) followed by putrescine and cadaverine (<15 mg/kg). In contrast, B-sausages resulted in earlier and much greater amine production, and cadaverine, tyramine, and putrescine levels were 50-, 2.6-, and 6.5-fold higher than those of A-sausages. Other biogenic amines, such as octopamine, tryptamine, phenylethylamine, and histamine were also produced in B-sausages. The higher proteolysis and the lower pH of B-sausages might have favored the decarboxylase activity of microorganisms. Biogenic amine contents of sausages during storage depended on the raw materials used and storage temperature. No significant modification on the amine contents was observed during the storage of A-sausages at either temperature. Greater changes occurred in B-sausages stored at 15 degrees C than in those stored at 4 degrees C. Higher temperatures favored proteolytic and decarboxylase reactions, resulting in increased amine concentrations after storage.

Animals↗
PubMed1999

Modulation of the light response by cAMP in Drosophila photoreceptors.

Phototransduction in Drosophila is mediated by a G-protein-coupled phospholipase C transduction cascade in which each absorbed photon generates a discrete electrical event, the quantum bump. In whole-cell voltage-clamp recordings, cAMP, as well as its nonhydrolyzable and membrane-permeant analogs 8-bromo-cAMP (8-Br-cAMP) and dibutyryl-cAMP, slowed down the macroscopic light response by increasing quantum bump latency, without changes in bump amplitude or duration. In contrast, cGMP or 8-Br-cGMP had no effect on light response amplitude or kinetics. None of the cyclic nucleotides activated any channels in the plasma membrane. The effects of cAMP were mimicked by application of the non-specific phosphodiesterase inhibitor IBMX and the adenylyl cyclase activator forskolin; zaprinast, a specific cGMP-phosphodiesterase inhibitor, was ineffective. Bump latency was also increased by targeted expression of either an activated G(s) alpha subunit, which increased endogenous adenylyl cyclase activity, or an activated catalytic protein kinase A (PKA) subunit. The action of IBMX was blocked by pretreatment with the PKA inhibitor H-89. The effects of cAMP were abolished in mutants of the ninaC gene, suggesting this nonconventional myosin as a possible target for PKA-mediated phosphorylation. Dopamine (10 microM) and octopamine (100 microM) mimicked the effects of cAMP. These results indicate the existence of a G-protein-coupled adenylyl cyclase pathway in Drosophila photoreceptors, which modulates the phospholipase C-based phototransduction cascade.

Animals↗
PubMed2000

Patterns of shaker family gene expression in single identified neurons of the American lobster, Homarus americanus.

The patterns of expression of voltage gated potassium channel genes of the Shaker family have been mapped in identified neurons of the lobster (Homarus americanus) ventral nerve cord using a single cell reverse transcriptase polymerase chain reaction procedure. Using specific oligonucleotides derived from the sequences of the shaker, shab, and shaw genes of the spiny lobster, Panulirus interruptus, we detected the corresponding potassium channel DNA fragments from Homarus americanus. The Homarus DNA fragments are 87-98% identical at the nucleotide level to the Panulirus DNA fragments. We used the Panulirus primers to measure the complement of RNAs for shaker, shab, and shaw in single identified cells that use GABA, glutamate, octopamine or serotonin as chemical messengers. Shaker and shaw RNAs were found in all four identified neuron types but shab RNA was not detected in serotonin cells under the present experimental conditions. All cells expressed alpha-tubulin RNA, which serves as an internal control suggesting that cells are intact after dissection. In glial cells that surround the neuronal cell bodies, the potassium channel genes are expressed at low to non-detectable levels.

Animals↗
PubMed2000

Physiological and pharmacological studies on nematodes.

Classical transmitters and neuroactive peptides act as transmitters or modulators within the central and peripheral nervous systems of nematodes, for example Ascaris suum and Caenorhabditis elegans. Acetylcholine (ACh) and gamma-aminobutyric acid (GABA) are respectively the excitatory and inhibitory transmitters onto somatic body wall muscle while 5-hydroxytrypamine (5-HT) is the excitatory transmitter onto pharyngeal muscle. 5-HT also reduces ACh-induced contractions of somatic muscle and this action of 5-HT is mediated through activation of adenylate cyclase while that on pharyngeal muscle is mediated through inositol phosphate activation. Glutamate, dopamine and octopamine also have transmitter roles in nematodes. Neuroactive peptides of the RFamide family can excite somatic muscle, for example, AF-1 (KNEFIRFamide), AF-2 (KHEYLRFamide), AF-3 (AVPGVLRFamide) and AF-4 (GDVPGVLRFamide) or inhibit and relax this muscle, for example, PF-1 (SDPNFLRFamide), PF-2 (SADPNFLRFamide) and PF-4 (KPNlRFamide). In addition PF-3 (AF-8) (KSAYMRFamide) has a biphasic action on pharyngeal muscle, excitation followed by inhibition while AF-1 only inhibits this muscle. The peptide effects can be either pre- or postsynaptic or both and are likely to be mediated through second messenger systems. In addition these peptides modulate the action of classical transmitters, particularly ACh.

Acetylcholine↗
PubMed2001

[Interaction of hormones in controlling reproductive function of Drosophila females under stressful conditions is genetically determined].

The effect of heat stress (38 degrees C) on the content of octopamine (OA) and 20-hydroxyecdysone (20HE) was studied under normal and stressful conditions in adult flies of Drosophila virilis lines contrasting in the level of the juvenile hormone (JH). The wild-type flies (line 101) exhibited a pronounced sex dimorphism for the content of both OA and 20HE, which was substantially lower in this line than in flies of the mutant line 147. The level of both hormones increased in flies of line 101 exposed to heat stress, whereas it remained unchanged in flies of line 147 under the same conditions. The effect of heat stress on the level of JH metabolism and fertility was also studied in D. melanogaster wild-type lines and lines carrying mutations in genes responsible for OA and DA syntheses. In octopamineless females of the T beta hnM18 line and in females of the Ste line characterized by a doubled content of DA, JH degradation differed from normal: it was increased in both young and mature T beta hnM18 females, while decreased in young and increased in mature Ste flies. Fertility was substantially lower in the Ste than in the wild-type line. Flies of all of the D. melanogaster lines produced a stress response; however, in mutant lines, both fertility and stress reactivity of the systems controlling JH metabolism differed significantly from that of the wild-type lines. The role of JH, 20HE, OA, and DA interaction in regulation of Drosophila reproduction under stressful conditions is discussed.

Animals↗
PubMed2003

Presynaptic impairment of synaptic transmission in Drosophila embryos lacking Gs(alpha).

Gs(alpha) is a subunit of the heterotrimeric G-protein complex, expressed ubiquitously in all types of cells, including neurons. Drosophila larvae, which have mutations in the Gs(alpha) gene, are lethargic, suggesting an impairment of neuronal functions. In this study, we examined synaptic transmission at the neuromuscular synapse in Gs(alpha)-null (dgsR60) embryos shortly before they hatched. At low-frequency nerve stimulation, synaptic transmission in mutant embryos was not very different from that in controls. In contrast, facilitation during tetanic stimulation was minimal in dgsR60, and no post-tetanic potentiation was observed. Miniature synaptic currents (mSCs) were slightly smaller in amplitude and less frequent in dgsR60 embryos in normal-K+ saline. In high-K+ saline, mSCs with distinctly large amplitude occurred frequently in controls at late embryonic stages, whereas those mSCs were rarely observed in dgsR60 embryos, suggesting a developmental defect in the mutant. Using the Gal4-UAS expression system, we found that these phenotypes in dgsR60 were caused predominantly by lack of Gs(alpha) in presynaptic neurons and not in postsynaptic muscles. To test whether Gs(alpha) couples presynaptic modulator receptors to adenylyl cyclase (AC), we examined the responses of two known G-protein-coupled receptors in dgsR60 embryos. Both metabotropic glutamate and octopamine receptor responses were indistinguishable from those of controls, indicating that these receptors are not linked to AC by Gs(alpha). We therefore suggest that synaptic transmission is compromised in dgsR60 embryos because of presynaptic defects in two distinct processes; one is uncoupling between the yet-to-be-known modulator receptor and AC activation, and the other is a defect in synapse formation.

Adenylyl Cyclases↗
PubMed1997

[Hepatic encephalopathy. Pathogenesis and therapy].

Hepatic encephalopathy is a frequent complication of cirrhosis. Portal-systemic shunts and depression of hepatic function are the primary underlying abnormalities. Arterial blood ammonia levels are frequently elevated during hepatic encephalopathy and are lower when a clinical improvement is established. Glutamine synthesis is part of the metabolic pathway for ammonia cerebral detoxification that induces ATP and glutamate (excitatory neurotransmitter) depletion. Plasma levels of branched chain amino acids are reduced in patients with cirrhosis, this event allows aromatic amino acids to cross the hemato-liquoral barrier through exchange with glutamine. Cerebral excess of aromatic amino acids promotes the synthesis of octopamine and feniletiletanolamine, weak neurotransmitters. Benzodiazepine-like substances may affect GABA-ergic transmission by interacting with their receptors on the GABA-benzodiazepine complex. Therapy is aimed at controlling the events that may precipitate the acute encephalopathy, at reducing the ammonia levels, and correcting the neurotransmission abnormalities.

English Abstract↗
PubMed1991

Neurotransmitters and neuromodulators controlling the anterior byssus retractor muscle of Mytilus edulis.

1. The anterior byssus retractor muscle (ABRM) of Mytilus edulis is innervated by at least two kinds of nerves, excitatory and relaxing nerves. The principal neurotransmitters released from these nerves have been shown to be acetylcholine and serotonin, respectively. 2. Some other monoamines, such as dopamine and octopamine, and various peptides, such as FMRFamide-related peptides, Mytilus inhibitory peptides, SCP-related peptides and a catch-relaxing peptide, may also be involved in the regulation of the muscle as neurotransmitters or neuromodulators. 3. The ABRM seems to be typical of invertebrate muscles controlled by multiple neurotransmitters and neuromodulators.

Amino Acid Sequence↗
PubMed2006

Spectrophotometric and liquid chromatographic determination of dopamine from pharmaceutical preparations using acetyl acetone as derivatizing reagent.

Dopamine (DA) has been determined by spectrophotometry and by liquid chromatography as derivatives of acetylacetone (AA). The liquid chromatography of DA was carried out in the presence of hydroxyproline (HP), octopamine (OP) and tyramine (TY). The separation was obtained from Phenomenex C-18 column 5 pm (150 x 4.6 mm id) by isocratic elution with methanol: acetonitrile: water (45: 6: 49 v/v/v), UV detection was at 320 nm. Linear calibration curves were obtained for each with 2.5-40.0 microgml(-1) with detection limits in the range 1.8-80 ng injection(-1) (10 microl). The dopamine was determined in pharmaceutical preparations with coefficient of variation (CV) within 0.7-1.5%.

Calibration↗
PubMed1990

Alternative catecholamine pathways after tyrosine hydroxylase inhibition in malignant pheochromocytoma.

A suppression of norepinephrine, epinephrine, and its metabolites in malignant pheochromocytoma by metyrosine was associated with an increase in tyrosine, plasma DOPA, and sulfate esters of DOPA and dopamine, followed, with continuing metyrosine administration, by a further rise of both DOPA sulfate and dopamine sulfate. Urinary dopamine progressively increased in the course of metyrosine treatment, and this, along with the increase of the dopamine metabolite, dihydroxyphenylethanol, and plasma dopamine sulfate, occurred in the absence of any change in plasma dopamine. The octopamine metabolite para-hydroxyphenylglycol, which was initially elevated at least 10-fold, also increased after metyrosine treatment. The unexpected increase of DOPA (progressively more converted toward DOPA sulfate) in the presence of tyrosine hydroxylase inhibition and increase in tyrosine may result from channeling the excess tyrosine toward DOPA and melanin through tyrosinase. Increases in plasma dopamine sulfate and urinary dopamine suggest that dopamine sulfate may be generated via DOPA sulfate and urinary dopamine may originate from circulating DOPA. Tyrosine hydroxylase inhibition may thus result in DOPA generation in non-catecholamine-producing tissues by an alternative pathway. The resulting progressive increase in DOPA and its sulfate may lead to increased urinary dopamine. DOPA sulfate may be an alternative source of dopamine sulfate.

Adrenal Gland Neoplasms↗
PubMed1990

Neurotransmitters in hepatic encephalopathy.

The pathogenesis of hepatic encephalopathy (HE), a neuropsychiatric disorder resulting from liver failure, is still a matter of debate. Recently attention has been focused on brain neurotransmitters. The accumulating evidence indicates that the imbalanced metabolism and turnover as well as the altered functions of neurotransmitters (dopamine, noradrenaline, serotonin, GABA) and false neurotransmitters (phenylethanolamine, octopamine, synephrine) may be of high importance in the pathomechanism of HE. Our data permit adding histamine (HA) to the multifactorial pathogenesis of HE. The enhanced rate of histidine influx into the brain following portocaval anastomosis and a dramatic increase in the HA content in the hypothalamus may suggest the involvement of HA in the symptomatology of hepatic encephalopathy.

Animals↗
PubMed1979

Structure activity relationships between catecholamines and the alpha-adrenergic receptor responsible for the aggregation of human platelets by epinephrine.

PEA is a potent inhibitor (Ki approximately 13 microM) of human platelet aggregation induced by epinephrine. This led us to perform an SAR study of a congeneric series of compounds in an effort to identify the molecular components of epinephrine critical to its aggregating effect upon human platelets. Phenylethanolamine was similar to PEA in inhibitory potency. However, hydroxylation of the phenyl ring diminished the inhibitory effect (Ki tyramine approximately 87 microM; Ki octopamine approximately 88 microM). Dopamine, the weakest inhibitor (Ki approximately 150 microM), was a partial agonist capable of inducing platelet aggregation in some samples of PRP. The order of potency of catecholamines as aggregating agents was epinephrine greater than norepinephrine greater than Epinine greater than dopamine. Phenylephrine, the prototype alpha-agonist, did not induce aggregation but was a potent inhibitor (Ki approximately 12 microM) of the aggregation induced by epinephrine. Isoproterenol, the prototype beta-agonist, was neither an aggregant nor an inhibitor of epinephrine-induced platelet aggregation. These findings suggest that the binding of epinephrine to the alpha-adrenergic receptor responsible for platelet aggregation is accomplished by the N-methyl amino group whereas intrinsic aggregating activity is a function of the catechol moiety.

2-Hydroxyphenethylamine↗
PubMed1987

Cyclic AMP-induced phosphorylation of 27.5-kDa protein(s) in larval brains of normal and memory-mutant Drosophila melanogaster.

Whole brains dissected from third-instar larvae of Drosophila melanogaster increase their cAMP content when incubated with octopamine, dopamine and serotonin, especially in the presence of theophylline, a phosphodiesterase inhibitor. The most pronounced rise in cAMP was produced by forskolin. When brains prelabelled with [32P]orthophosphate were subjected to these treatments, the increased labelling of 27.5-kDa protein(s) of pI 6.3-6.6 (substrate A) was observed in all cases, as revealed by two-dimensional gel electrophoresis and autoradiography. Labelling of substrate A was enhanced without any drug addition in brains of the dunceM11 mutant strain, which has abnormally high basal cAMP levels. The labelling of substrate A was also promoted by the potassium channel blocker 4-aminopyridine. The data suggest that in Drosophila larval brain the 27.5-kDa protein is a target of cAMP-triggered phosphorylation and may be related to potassium channel(s).

Animals↗
PubMed1986

Histological and pharmacological investigations of the two symmetrically situated giant neurons, RPeNLN and LPeNLN, identified on the anterior surface of the pedal ganglia of an African giant snail (Achatina fulica Férussac).

Morphological and pharmacological investigations were made of two giant neurons, RPeNLN (right pedal nerve large neuron) and LPeNLN (left pedal nerve large neuron), situated symmetrically on the anterior surface of the pedal ganglia of an African giant snail (Achatina fulica Férussac). The two neurons (about 250-300 microns in diameter) were the largest ones identified in the ganglia of the snail species. The axonal pathways of the two neurons were symmetrical; of their four main axonal branches, the three main branches innervated the ipsilateral pedal nerves, whereas the last main branch projected to the contralateral pedal nerves. The pharmacological features of the two neurons were very similar. Both were inhibited markedly by dopamine [minimum effective concentrations (MECs): 3 X 10(-6)-10(-5) M], DL-octopamine (MECs: 2 X 10(-6)-2 X 10(-5) M), 5-hydroxytryptamine (MEC: 3 X 10(-6) M), GABA (MEC: 3 X 10(-4) M), L-homocysteic acid (MECs: 3 X 10(-5)-10(-4) M) and erythro-beta-hydroxy-L-glutamic acid (MEC: 3 X 10(-5) M). Acetylcholine showed varied effects, either excitatory or inhibitory, on the two neurons examined. No substances were found to have any marked excitatory effects on the neurons.

Animals↗