Effect of various insecticides on the larval growth and biogenic amine levels of Tribolium castaneum Herbst

Various insecticides reduced larval growth of the red flour beetle (tribolium castaneum Herbst) and various biogenic amines, including octopamine (OA), dopamine (DA), serotonin (5-HT), epinephrine (E), norepinephrine (NE), their precursors and metabolites in the insects were measured by high-performance liquid chromatography coupled with electrochemical detection. Tyrosine occurred in the highest concentration followed by OA, tryptophan and 3,4-dihydroxymandelic acid (DOMA). Tyramine (a precursor of OA in the biosynthetic pathway), synephrine (N-methyl OA), DA, 5-HT, E, NE and their related substances occurred in extremely low quantities compared with OA. The insects were stressed by various insecticides, which resulted in a dramatic change of biogenic amine levels: the OA levels increased, whereas the levels of other biogenic amines and related substances decreased.     

Developmental Changes in Biogenic Amine Levels in the Central Nervous System and the Haemolymph of the Eastern Death's Head Hawk Moth,Acherontia styx (Lepidoptera: Sphingidae)

In an effort to understand the role of biogenic amines in insect development, changes in the levels of octopamine (OA), dopamine (DA), epinephrine (E), norepinephrine (NE), and serotonin (5-HT) in the brain, the optic lobes and the haemolymph of different developmental stages of Acherontia styx were analyzed using HPLC with electrochemical detector. In the brain, OA was the most abundant monoamine. DA, OA, and E levels in larvae peaked around the wandering stage (W). A dramatic increase in DA, 5-HT, and E levels was observed in the brain of the adult as compared to the pupal stage. NE, however, was not detected in the brain of most stages of the insect, except in the brain of 20-day-old pupae and adults. A 3-fold increase in OA levels was observed in the optic lobes of the adult as compared to late pupal stage. No changes were observed for E, DA, and 5-HT. NE was not detected in the optic lobes. In the haemolymph of 5^th instar larvae, OA was also the most abundant amine. Both DA and OA peaked prior to the onset of the W stage. In contrast, E and NE concentrations decreased with development of the 5^th instar larvae. 5-HT was not detected in the haemolymph. Finally, different profiles for amine levels were observed for the two forms of the 5^th instar larvae (green vs brown). These results are interpreted in the light of the role of biogenic amines and their relation to development in the nervous system of lepidopteran insects.     

The role of biogenic amines in the control of blood glucose level in the decapod crustacean,Carcinus maenas L.

1. Administration of biogenic amines into intact Carcinus maenas induces dose- and timedependent elevation of hemolymph glucose level.2. Removal of the neurosecretory centre containing the crustacean hyperglycemic hormone (CHH) by ablation of the eyestalks did not induce hypoglycemia.3. Injection of dopamine (DA) into eyestalkless crabs showed no hyperglycemic effect, while serotonin (5-HT), epinephrine (E), norepinephrine (NE), and octopamine (OA) elevated glucose levels.4. The dopaminergic effect was significantly reduced by administration of trifluoperazine (TFP).5. 5-HT and OA were found to be strong elevators of glucose levels, while the other biogenic amines had moderate effects only.6. The results indicate, that DA exerts its hyperglycemic effect by stimulating the release of CHH from the eyestalk neurosecretory centre. Elevation of hemolymph glucose level by 5-HT, OA, E, and NE, occurs independently of CHH.     

Polymorphism of the COMT,MAO, DAT,NET and 5-HTT Genes,and Biogenic Amines in Parkinson’s Disease

Epinephrine (E) and sympathetic nerve stimulation were described by Thomas Renton Elliott in 1905 for the first time. Dopamine (DA), norepinephrine (NE), E, and serotonin (5-HT) belong to the classic biogenic amines (or monoamines). Parkinson’s disease (PD) is among the diseases in which it has been established that catecholamines may account for the neurodegeneration of central and peripheral catecholamine neural systems. PD is a chronic and progressive neurological disorder characterized by resting tremor, rigidity, and bradykinesia, affecting 2% of individuals above the age of 65 years. This disorder is a result of degeneration of DA-producing neurons of the substantia nigra and a significant loss of noradrenergic neurons in the locus coeruleus. In PD and other related neurodegerative diseases, catecholamines play the role of endogenous neurotoxins. Catechol-O-methyltransferase (COMT) and/or monoamine oxidase (MAO) catalyze the metabolism of monoamines. However, the monoamine transporters for DA, NE, and 5-HT namely DAT, NET, and SERT, respectively regulate the monoamine concentration. The metabolism of catecholamines and 5-HT involves common factors. Monoamine transporters represent targets for many pharmacological agents that affect brain function, including psychostimulators and antidepressants. In PD, polymorphisms of the COMT, MAO, DAT, NET, and 5- HTT genes may change the levels of biogenic amines and their metabolic products. The currently available therapies for PD improve the symptoms but do not halt the progression of the disease. The most effective treatment for PD patients is therapy with L-dopa. Combined therapy for PD involves a DA agonist and decarboxylase, MAOs and COMT inhibitors, and is the current optimal form of PD treatment maintaining monoamine balance.     

Diurnal alterations of catecholamines, indoleamines and their metabolites in specific brain regions of the mouse

1. The diurnal variations of regional brain concentrations of dopamine (DA), norepinephrine (NE), serotonin (5-HT) and metabolites were determined in unperturbed male CD-1 mice. Determinations were made every 4 hr for 24 hr. 2. The most striking and significant variations in biogenic amines were seen in the hypothalamus, where concentrations of NE, DA and 5-HT varied in a rhythmic pattern and as much as two-fold during this period. 3. In some cases, daily alterations in parent biogenic amines were reflected by concurrent changes in their metabolites. 4. Since concentrations of neurotransmitters in the brain are often used as an indicator of stress and/or toxicity, these data should provide an accurate data base allowing for more accurate interpretation of results.     

Regulation of pyridoxal-5′-phosphate level by biogenic amines in mouse brain

We investigated the relationship between the concentration of pyridoxal-5′-phosphate (PLP) and biogenic amine in mouse brain. The production of PLP from pyridoxal (PL) by pyridoxal kinase (PLK) was inhibited by the addition of dopamine (DA), norepinephrine (NE) and 5-hydroxytryptamine (5-HT), but not by that of epinephrine and N-acetyl-serotonin. DA and NE were combined with PLP by a non-enzymatic reaction, whereas 5-HT was bound only slightly with PLP. The conjugated product of PLP with DA was also detected by HPLC analysis when PLK activity was assayed using PL as a substrate in the presence of DA. In an in vivo investigation, the depletion of DA and 5-HT in mouse brain after an intraperitoneal injection of 5 mg/kg reserpine, led to slight elevation of the PLP level to 120% of the control level. By contrast, the increase in DA in the brain caused by intraperitoneal administration of 150 mg/kg L-DOPA caused the PLP concentration to decrease to 70% of the control level. However, no change in PLK activity in the brain was observed when the mice were treated with either reserpine or L-DOPA. These results suggested that the level of PLP in mouse brain was partly regulated by the concentration of biogenic amines, such as DA, NE and 5-HT, without apparent induction of PLK.     

Biogenic amine levels in the central nervous system and haemolymph of the silkworm,Bombyx mori

1. A wide range of biogenic amines and related metabolites were quantified in the silkworm, Bombyx mon from fourth instar to post-spinning stage using a three-dimensional HPLC system with multiple coulometric electrochemical detection.2. In the central nervous system, metabolic pathways such as tyrosin (TYR-4)-dopa (L-DOPA)-dopamine (DA), TYR-4-tyramine (TYRA), tryptophan (TRP)-5-hydroxytryptamine (5-HT) were found. In some stages, normetanephrine (NMN), 3,4-dihydroxyphenylethylene (DOPAC) and 5-hydroxyindoleacetic acid (5HIAA) were detected.3. In the haemolymph, TRY-4-L-DOPA-DA pathway was mainly found. 3-Methoxy-4-hydroxy- phenyl glycol (MHPG) in fourth instar and norepinephrine (NE) in fifth instar were also detected. 5-HT was lacking.4. Metabolic pathways of biogenic amines in the central nervous system and haemolymph were discussed.     

Metal chelates in the storage and transport of neurotransmitters: formation of mixed ligand chelates of Mg 2+ -ATP with biogenic amines

Abstract— Quantitative studies on the interactions of adenosine-triphosphate and several biogenic amines with magnesium ion have been carried out in an attempt to correlate the thermodynamic stabilities of the metal-binding of the amines with the in vivo affinities of the amines for granule-binding. Equilibrium data indicate that in each of the ternary chelate systems (viz. Mg²⁺-ATP-amine), the predominant reaction in the pH range 3.0–7.0 is the formation of a magnesium-ATP chelate with a stability constant, log K_ML=3.22 ± 0.02. Each of the biogenic amines coordinates with Mg²⁺-ATP system in the pH range 7.0–10.5 to form the mixed ligand chelate (or ternary chelate), Mg²⁺-ATP-amine(1:1:1). The stability constants for the binding of the amines with Mg²⁺-ATP are: (i) norepinephrine (NE) = 2.34 ± 0.32; (ii) epinephrine (E) = 2.95 ± 0.08; (iii) dopamine (DA) = 3.05 ± 0.06; (iv) octopamine (OA) = 1.93 ± 0.12; (v) 6-hydroxydopamine (6-HDA) = 2.42 ± 0.14; (vi) 3-methoxynorephedrine (MeN) =2.76 ± 0.09; (vii) amphetamine (AA) =2.09 ± 0.05; (viii) tyramine (TA) = 2.60 ± 0.04; (ix) phenylethylamine (PEA) = 0. A general correlation is indicated between the stability constants (binding strengths) of the amine chelates and the metal-binding functionalities of the amines on the one hand and their vesicular binding characteristics in in vivo systems on the other (Carlsson and Waldeck , 1966). The Mg²⁺-ATP-dependant amine storage mechanism of KIRSHNER (1962a;b) and Carlsson , Hillårp and Waldeck (1963) is discussed both in the light of the data on metal chelate stability and of a significant modification of metal coordination hypothesis.     

The effects of sodium pentachlorophenate, diet and sampling procedure on amine and tryptophan concentrations in the brain of rainbow trout, Salmo gairdneri Richardson

The response of rainbow trout (Salmo gairdneri Richardson) to sublethal levels of sodium pentachlorophenate (NaPCP) was determined by measuring brain concentrations of the amines dopamine (DA), norepinephrine (NE), 5-hydroxytryptamine (5-HT) and the free amino acid tryptophan (TP) using high performance liquid chromatography with electrochemical detection. Sodium pentachlorophenate had no major effect on the concentrations of the biogenic amines. Mean control concentrations (ng g⁻¹ brain, S.E.) were: DA, 146.2, 9.9; NE, 205.8, 16.6; and 5-HT, 110.5, 8.8. There was a significant dose-dependent increase in TP concentration. Fish exposed to 200ng I⁻¹ NaPCP showed a 128% increase in TP level relative to the mean control concentration of 1980 (50) ng g⁻¹ brain. The effects of diets varying in lipid and carbohydrate content, anaesthetization with tricaine methanesulphonate or 2-phenoxyethanol, and electroshock were also investigated. No differences between treatment groups were detected.     

Previous stress increases in vivo biogenic amine response to swim stress

In vivo microdialysis was used to determine biogenic amines in medial prefrontal cortex of rats exposed to eight minutes of swim stress on two consecutive days. On the first day of stress, norepinephrine (NE) efflux increased by 183% over baseline after stress, while dopamine (DA) and serotonin (5-HT) remained stable throughout. On the second day of stress, a robust increase was observed in all 3 neurotransmitters measured, with (NE), (DA), and (5-HT) increasing by 310%, 441% and 496% respectively, and remaining elevated for an hour or more after stress. This suggests that the first exposure to swim stress, while not causing dramatic changes in biogenic amine release, may sensitize biogenic amines in medial prefrontal cortex to subsequent swim stress. Our results also serve as preliminary data concerning the neurochemical changes which might underlie the forced swimming model of behavioral despair.     

Microiontophoresis of biogenic amines on cortical neurons: amounts of NA, DA and 5-HT ejected, compared with tissue content

The present series of studies were carried out to quantify the amounts of dopamine (DA), noradrenaline (NA) and serotonin (5-HT) ejected from iontophoresis micropipettes and that produce inhibitory and modulatory effects on cortical neurons, in the frontoparietal cortex of the rat and in the occipital cortex of the cat. Using radioactive isotopes of the biogenic amines the effective transport number (n) was found to be 0.08 for DA; 0.13 for NA, and 0.22 for 5-HT. In addition, similar determinations were made, for comparison purposes, of the transport numbers of the neurotransmitters acetylcholine (ACh; n = 0.44), gamma-amino-n-butyrate (GABA, n = 13), and glutamate (GLU; n = 0.27). The quantities ejected under in vivo conditions were then estimated using Faraday's formula and fell in the pmol range (10(-12) mol). The effects of DA, NA and 5-HT on cortical units were studied; the amounts ejected were compared with the endogenous tissue content of these amines, determined by means of specific and sensitive radioenzymatic assays in the regions where the microiontophoretic experiments were performed. These results are discussed in the light of the anatomical, biochemical and electrophysiological data suggesting a modulatory role for the biogenic amines in the cerebral neocortex.     

Biogenic amines and DOPA in the central nervous system of decapod crustaceans

The biogenic amines serotonin (5-HT), dopamine (DA), noradrenaline (NA), octopamine (OA) and the amino acid dihydroxyphenylalanine (DOPA) were identified and measured in the brain and the eyestalks of five decapod crustacean species using high pressure liquid chromatography (HPLC) with electrochemical detection. The amounts fall within 0.01-1.1 micrograms/g or 0.17-60 pmoles, and OA is the dominating amine in most species. THe DOPA levels in many of the species varied considerably between different measurements. It is concluded that the biogenic amines and DOPA are ubiquitous in the central nervous system of decapod crustaceans and the presence of NA and DOPA increases the number of presumed neurotransmitter/modulator candidates in the crustacean nervous system.     

Alternating extremely low frequency magnetic field increases turnover of dopamine and serotonin in rat frontal cortex

The aim of this study was to evaluate the influence of an extremely low frequency sinusoidal magnetic field (ELF MF) with frequency of 10 Hz and intensity of 1.8-3.8 mT on the levels of the biogenic amines dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 3-methoxytyramine (3-MT), 5-hydroxytryptamine (5-HT), 5-hydroxyindolacetic acid (5-HIAA), and noradrenaline (NA), as well as on DA and 5-HT turnover in corpus striatum and frontal cortex of adult male Wistar rats. We found that ELF MF exposure for 14 days, 1 h daily, did not influence the level of the examined biogenic amines and metabolites, but increased the rate of synthesis (turnover) of DA and 5-HT in rat frontal cortex as compared to control, sham exposed rats. On the basis of the present results and our previous findings, extremely low frequency magnetic field (ELF MF) exposure has been found to alter both turnover and receptor reactivity of monoaminergic systems, as well as some behaviors induced by these systems or their agonists and antagonists.     

Effects of ethanol on brain monoamine content of spontaneously hypertensive rats (SHR)

Spontaneously hypertensive rats (SHR) were administered either 2.4 g/kg ethanol or an isocaloric glucose daily for 4 weeks and the levels of norepinephrine (NE), epinephrine (EP), dopamine (DA), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in different brain regions were determined. Results indicated a 3-fold increase in NE level in brain stem and hypothalamus and more than 2-fold increase in DA in corpus striatum in alcohol-treated rats as compared to controls. There was a significant increase in the level of DA in the corpus striatum but the levels in cerebral cortex, brain stem and hippocampus were decreased instead. Decreases in 5-HT levels were found in hypothalamus, brain stem, cortex and cerebellum of alcohol-treated brain as compared to untreated controls. These results indicate alterations of the biogenic amine contents in different regions of the SHR brain after chronic ethanol ingestion. Since stimulated release of biogenic amines in the SHR brain has been implicated in the regulation of blood pressure, changes due to ethanol ingestion may be a risk factor in hypertensive patients.     

Amine modulation of the neurogenic Limulus heart

(1) The biogenic amines octopamine (OCT), dopamine (DA), epinephrine (E), and norepinephrine (NE) cause dose-dependent increases in both the rate and amplitude of contractions of the isolated Limulus heart-cardiac ganglion. Their relative ability to produce this excitation is OCT greater than DA approximately the same as E greater than NE. (2) The excitatory effects of all these amines are antagonized by the alpha-adrenergic blocker phentolamine and the dopaminergic antagonist haloperidol. The beta-adrenergic antagonist dichloroisoproterenol slightly reduces amine excitation, but is also a partial agonist. The beta-adrenergic antagonist propanolol, the alpha-blocker phenoxybenzamine, and the serotonin antagonist metergoline are ineffective. (3) In addition to their excitatory effects, DA and, to a lesser extent, NE initially reduce contraction rate and amplitude. (4) The transient inhibition is eliminated selectively by metergoline and is unaffected by the other antagonists. (5) The amines all increase the frequency of cardiac ganglion electrical bursting activity, whether ganglia are isolated or attached to cardiac muscle. Dopamine and NE also transiently inhibit the cardiac ganglion. (6) The amines do not alter myocardial resting tension, contractility, or membrane potential. (7) These amines appear to exert their modulatory effects on Limulus heart by altering the properties of the neurons which comprise its cardiac ganglion.     

Biogenic amines in the two-spotted spider mite

Whole body extracts of the two-spotted spider mite (Tetranychus urticae Koch) were analyzed using a 16-channel electrochemical array high performance liquid chromatography (HPLC)-based detection system that allows the simultaneous isolation and identification of a variety of biogenic amines. The spider mite extracts were found to contain the biogenic amines octopamine, dopamine, and 5-hydroxytryptamine (5-HT), as well as several precursors and metabolites including tyrosine, tyramine, tryptophan, and N-acetyl octopamine. Differences in the levels of biogenic amines were observed between eggs and the adult stages and between males and females. This is the first direct determination of biogenic amines in the Tetranychidae and the first demonstration of 5-HT in any mite species. © 1994 Wiley-Liss, Inc.     

Effect of past and present behavioural specialization on brain levels of biogenic amines in workers of the red wood ant Formica polyctena

Social insect workers usually participate first in intranidal tasks (i.e. act as nurses within the nest) and then switch to extranidal tasks and become foragers. However, foragers sometimes switch back again to brood care and become reverted nurses. Behavioural and physiological correlates of the transition nurse–forager (behavioural maturation) and forager–reverted nurse (behavioural reversion) are relatively well known in the honeybee, although they are less explored in ants. To understand better the role of biogenic amines in ant behavioural maturation and behavioural reversion, the levels of octopamine (OA), dopamine (DA) and serotonin (5‐HT) are examined in the brains of nurses, foragers and reverted nurses of the red wood ant Formica polyctena Först. (Hymenoptera: Formicidae). Brain OA levels and the ratios OA : DA and OA : 5‐HT are higher in nurses than in foragers and reverted nurses. Reverted nurses and foragers do not differ significantly with respect to brain biogenic amine levels and amine ratios. Biogenic amine levels in brains of workers of F. polyctena are thus maturation‐related rather than task‐related. This is one of the first studies of neurochemical correlates of ant behavioural maturation and the first attempt to identify neurobiological correlates of ant behavioural reversion. The data obtained provide further evidence that neurobiological processes underlying honeybee and ant behavioural maturation and behavioural reversion reveal important differences.     

Variations of brain biogenic amines in mature honeybees and induction of recruitment behavior

Mature honeybees (Apis mellifera L.) old enough to forage (>3 weeks) were segregated into three activity groups: waggle dancers (active foragers), followers of the dancers (potential recruits) and resting bees (not involved in foraging). Dopamine (DA) pathways in the brain of honeybees seemed to be involved in regulation of forager recruitment. Brain DA and N-β-alanyldopamine (NBAD) levels in the dancers were always higher than in followers, and an increased number of dancers was observed after feeding the colony dihydroxy-phenylalanine (DOPA). Dopamine is hypothesized to modulate the neural activity in the calyx of the mushroom bodies related to recruitment behavior. No consistant effect of octopamine (OA) or serotonin (5HT) on recruitment behavior was observed. Levels of all biogenic amines were strongly effected by season and day-to-day whether changes. Some diurnal changes were also observed.     

Exposure to extremely low-frequency magnetic field restores spinal cord injury-induced tonic pain and its related neurotransmitter concentration in the brain

Spinal cord injury (SCI) is unequivocally reported to produce hyperalgesia to phasic stimuli, while both hyper- and hypoalgesia to tonic stimuli. The former is spinally mediated and the latter centrally. Besides, its management is unsatisfactory. We report the effect of magnetic field (MF; 17.96 μT, 50 Hz) on tonic pain behavior and related neurotransmitters in the brain of complete thoracic (T13) SCI rats at week 8. Adult male Wistar rats were divided into Sham, SCI and SCI+MF groups. Formalin-pain behavior was compared utilizing 5 min block pain rating (PR), 60 min session-PR, time spent in various categories of increasing pain (T0–T3) and flinch incidences. Serotonin (5-HT), dopamine (DA), norepinepherine (NE), gamma-aminobutyric acid (GABA), glutamate and glycine were estimated in brain tissue by liquid chromatography–mass spectrometry. Session-PR, block-PR and number of flinches were significantly lower, while time spent in categories 0–1 was higher in the SCI versus Sham group. These parameters were comparable in the SCI+MF versus Sham group. 5-HT concentration in cortex, remaining forebrain areas and brain stem (BS), was lower while GABA and NE were higher in BS of SCI, which were comparable with Sham in the SCI+MF group. The concentration of DA, glutamate and glycine was comparable amongst the groups. The data indicate significant hypoalgesia in formalin pain while increased in GABA, NE and decreased in 5-HT post-SCI, which were restored in the SCI+MF group. We suggest beneficial effect of chronic (2 h/day × 8 weeks) exposure to MF (50 Hz, 17.96 μT) on tonic pain that is mediated by 5-HT, GABA and NE in complete SCI rats.