Doses Of Deltamethrin Research Articles

The effects of combined exposure to the pyrethroids deltamethrin and S-bioallethrin on hippocampal inhibition and skeletal muscle hyperexcitability in rats

The default assumption that different pyrethroid insecticides, sharing a common mode of action, will show additivity of toxicity has not always been supported by in vitro measures, some of which have indicated antagonism. Our intention was to see whether the antagonism between pyrethroids of different classes seen in vitro could be reproduced in vivo. We therefore investigated the effects of single and combined exposures to two commonly used pyrethroids, deltamethrin (type II) and S-bioallethrin (type I) given intravenously to anaesthetised rats. We used two quantitative measures that are responsive to pyrethroids: the duration of prolongation of hippocampal dentate granule cell inhibition and the amplitude of the abnormal electromyogram discharge. At equi-toxic doses, S-bioallethrin extended the inter-stimulus interval evoking 50% inhibition in the hippocampus by 30+/-2.2 ms, and deltamethrin extended it by 199+/-21 ms. Combined administration of the same doses of deltamethrin and S-bioallethrin extended hippocampal inhibition by 164+/-14 ms, which did not differ significantly from the effect of deltamethrin alone. S-bioallethrin was without any effect on the electromyogram, and produced no significant change in the amplitude of the abnormal muscle discharges evoked by deltamethrin. The increase in arterial blood pressure evoked by the combination was significantly less than that evoked by either pyrethroid alone (p<0.001). In summary, although our electrophysiological indices provide no support for functional antagonism between these two pyrethroids, they also fail to indicate any summation of effect.

In Vitro Inhibition of Beauveria bassiana (Bals.) Vuill. Growth by Different Commonly Used Insecticides in Rice

In vitro inhibition of 13 different insecticides and one botanical on Beauveria bassiana growth was tested. Two doses of chemical insecticides, one at recommended dose (RD) and another at half of recommended dose (½. RD) and for botanicals three doses, first one at recommended and one at ½ and another at ½ of the recommended dose were tested. 100 per cent of mycelial growth was observed when the entomopathogen was grown in presence of monocrotophos (0.31%) and dichlorvos (0.12%). Cypermethrin, deltamethrin, alphamethrin and phosphamidon at recommended dose showed growth inhibition of < 50 per cent. Half of the recommended dose of deltamethrin was found having lowest inhibition (14.06 %).

Effects of deltamethrin on neurobehavioral development of offspring of intoxicated rats

To investigate the effects of deltamethrin on the filial brain nitric oxide synthase (NOS) activity and neurobehavioral development of the exposed lactational rats. Pregnant rats were randomizedly divided into the treated group and the control group. The treated group was administered orally with 3.35, 6.70 mg/kg deltamethrin every other day from postnatal day (PND) 1 to PND 19 while the control group was administered with the corn oil of same amount in the same period. The activity of NOS of filial brain and neurobehavioral functions of the filial rats were observed. The lactational survival rate (81.80%:78.60%) in both treated groups was decreased significantly (P < 0.01) compared with that in the control group. The body weight of filial rats on PND 10, 21 in 6.70 mg/kg DM treated group [(16.62 +/- 2.2 8), (31.34 +/- 6.94) g] was less than those in the control group (P < 0.05). The delayed time in the filial rats in 6.70 mg/kg group was (3.05 +/- 1.20) s and the positive rates of passive escaping response in 3.35 and 6.70 mg/kg DM treated group were 22.5% and 21.5% respectively. There was the trend of the developmental increase of the activity of filial brain NOS between PND 5 and PND 21 and the NOS activity of rat brain on PND 5 in 6.70 mg/kg group [(0.60 +/- 0.07) U.mg pro(-1).h(-1)] was lower than that in the control group (P < 0.05). Exposure to high dose of deltamethrin in lactational female rats will decrease the activity of NOS of brain and retard the neurobehavioral development of their filial rats.

Gill and kidney histopathology in the freshwater fish Cyprinus carpio after acute exposure to deltamethrin

The histopathological effects of deltamethrin on the gill and kidney tissues of the common carp, Cyprinus carpio were determined by light microscopy. The fish were exposed to 0.029 mg l −1 (50% of 96 h LC 50) and 0.041 mg l −1 (70% of 96 h LC 50) solutions of deltamethrin for short-term (96 h). The most common gill changes at all doses of deltamethrin were desquamation and necrosis. Besides, aneurism in secondary lamellae, lifting of the lamellar epithelium, oedema, epithelial hyperplasia and fusion of the secondary lamellae were reported. Lesions in the kidney tissues of fish exposed to deltamethrin were characterized by degeneration in the epithelial cells of renal tubule, pycnotic nuclei in the hematopoietic tissue, dilation of glomerular capillaries, degeneration of glomerulus, intracytoplasmatic vacuoles in epithelial cells of renal tubules with hypertrophied cells and narrowing of the tubular lumen.

The modulatory effect of deltamethrin on antioxidants in mice

Background Deltamethrin is a α-cyano pyrethroid insecticide used extensively in pest control. Although initially thought to be least toxic, a number of recent reports showed its toxicity in mammalian and non-mammalian laboratory and wildlife animal species. In fish, it is a potent oxidative stress-inducing agent. We studied the oxidative stress-inducing effect of deltamethrin in mice. Methods Male Swiss albino mice were orally administered 2 doses of deltamethrin viz., 5.6 and 18 mg/kg body weight (bw), for 15 days. Results Both the doses of deltamethrin significantly induced lipid peroxidation (LPO) in liver and kidney. Along with the induction of LPO, activities of vital antioxidant enzymes such as glutathione peroxidase (GPx), glutathione S-transferase (GST) and catalase (CAT) were also suppressed in both the tissues. Glutathione (GSH) level was also decreased. GSH decrease was more pronounced in kidney than the liver. Conclusion Toxicity of many chlorinated and organophosphate insecticides is mediated by the reactive oxygen species (ROS). Findings of the present investigation also suggest a role for ROS in deltamethrin toxicity. An increased LPO indicates that these ROS might have caused degradation of biomembrane in deltamethrin-exposed animals.

The inhibitory effects of deltamethrin on dopamine biosynthesis in rat PC12 cells

The inhibitory effects of deltamethrin (DM) on dopamine biosynthesis in PC12 cells were investigated. Levels of dopamine in PC12 cells were detected after treatment with different doses from 10 −4 M to 10 −6 M deltamethrin or combined with 20 μM or 50 μM l-3,4-dihydroxyphenylalanine ( l-Dopa) for 3 h or 12 h by HPLC. Flow cytometry (FCM) and RT-PCR technology were used to detect the levels of tyrosine hydroxylase (TH) mRNA and protein in PC12 cells treated with different doses of deltamethrin for 3 h or 12 h. Deltamethrin decreased the levels of dopamine, TH mRNA and TH protein in PC12 cells, and the increased dopamine levels induced by l-Dopa at 20–50 μM were also decreased by deltamethrin for 3 h or 12 h. These results indicate that deltamethrin decreases dopamine content by the inhibition of TH mRNA and protein level in PC12 cells and maybe also have inhibitory effect on aromatic l-amino acid decarboxylase.

Sublethal effects of commercial deltamethrin on the structure of the gill, liver and gut tissues of mosquitofish, Gambusia affinis: A microscopic study

The histopathological effects of deltamethrin on the gill, liver and gut tissues of the mosquitofish, Gambusia affinis were determined by light microscopy. The fish were exposed to two sublethal concentrations of deltamethrin (0.25–0.50 μg/l) for periods of 10, 20 and 30 days. The most common gill changes at all doses of deltamethrin were desquamation and necrosis. Besides, epithelial hypertrophy, lifting of the lamellar epithelium, oedema, dilatation of the capillaries primary lamellae, aneurism, epithelial hyperplasia and fusion of the secondary lamellae were other histopathological effects. Hepatic lesions in the liver tissues of fish exposed to deltamethrin were characterized by hypertrophy of hepatocytes, significant increase of kupffer cells, circulatory disturbances, focal necrosis, fatty degeneration, nuclear pycnosis and narrowing of sinusoids. Infiltration of mononuclear leucocyte and eosinophils towards lamina propria, necrosis were detected in gut tissues of fish after exposure to deltamethrin.

Deltamethrin exposure affects host resistance to Plasmodium infection in mice

Effects of exposure to deltamethrin on host resistance to malaria infection ( Plasmodium berghei) were examined in Swiss albino male mice. Four doses of deltamethrin were initially tested with two non-lethal doses, 5 and 10 mg/kg, selected for more detailed study. Survival times of infected mice did not change when they were exposed to the compound for 14 days before the infection. However, survival times were shortened when they were exposed to the compound, particularly at the high-dose, after and during the initial infection. Percent parasitemia of these animals also elevated faster than that of the control. Deltamethrin exposure also caused alteration of white blood cell populations. Specifically, total white blood cell and lymphocyte counts significantly decreased in the high-dose treated mice. Granulocyte counts were comparatively lower in both treated groups than that in the control. Red blood cells, hemoglobin, and hematocrit were not affected. The obtained results suggest that deltamethrin exhibits an immunosuppressive effect and negatively impacts host resistance to malaria infection.

Effects of deltamethrin on the apoptosis and the expression of caspase-3 in rat neural cells

To study the effect of deltamethrin on the apoptotic rate and the expression of caspase-3 in rat neural cells. Male Wistar rats were randomly divided into 5 groups: control, 5 h, 24 h, 48 h and 5 d exposed groups. Apoptotic rate and the expression of caspase-3 were measured by FACS420 Flow Cytometer; Ac-DEVD-pNa was used as a substrate to detect the activity of caspase-3. Apoptotic rates in 24 h, 48 h and 5 d exposed groups in hippocampus and cerebral cortex [hippocampus: (8.45 +/- 1.02)%, (9.44 +/- 1.14)%, (7.58 +/- 0.75)%; cerebral cortex: (7.90 +/- 0.49)%, (8.01 +/- 0.87)%, (7.97 +/- 0.41)% respectively] were higher than those in the control [hippocampus: (2.97 +/- 0.36)%; cerebral cortex: (3.50 +/- 0.48)%] (P < 0.01); the activity of caspase-3 in 5 h, 24 h and 48 h exposed groups (A(405) nm in hippocampus: 0.389 +/- 0.038, 0.472 +/- 0.041, 0.295 +/- 0.049; A(405) nm in cerebral cortex: 0.321 +/- 0.068, 0.429 +/- 0.077, 0.344 +/- 0.047) and 5 d group of hippocampus (0.246 +/- 0.065) were all higher than those of the control (hippocampus: 0.184 +/- 0.054; cerebral cortex: 0.198 +/- 0.049) (P < 0.05, P < 0.01); the expression of caspase-3 in 5 h, 24 h and 48 h exposed groups increased apparently while 5 d group did not. Exposure to high dose of deltamethrin would affect the apoptosis, the activity and expression of caspase-3 in rat neural cells. The increase in caspase-3 activity and expression occurred before the rising of neuronal apoptotic rate may be the upstream event of apoptosis.

Effects of sublethal deltamethrin on the chemical communication system and PBAN activity of Asian corn borer, Ostrinia furnacalis (Güenee).

Topically applied sublethal doses of deltamethrin may interrupt chemical communication between the two sexes of the Asian corn borer, Ostrinia furnacalis (Güenee), by affecting the probability of calling behavior, sex pheromone titer and PBAN-like activity. At the 1st, 2nd, and 4th day of post-treatment with deltamethrin (1 ng/moth), female O. furnacalis showed 32, 36, and 46% calling probabilities of control female moths, while the sex pheromone titer of females was only 15, 20, and 25% the amount of control females, respectively. The chemical communication system was significantly affected even at the 4th day post-treatment. By injections of 1, 1/2, 1/4, and 1/8 female equivalent of brain and subesophageol ganglion homogenate of 1 ng deltamethrin-treated females into decapitated females, female pheromone production was reduced to 64, 31, 30.7, and 8.1% of that of control female moths, respectively. This result appears to indicate that sublethal deltamethrin affected the activity of the PBAN-like factor of O. furnacalis.

Reproductive Effects of Deltamethrin on Male Offspring of Rats Exposed during Pregnancy and Lactation

The effects of low doses of deltamethrin administered to female rats on the reproductive system of male offspring were examined. The dams ( n=10–12/group) were treated daily by oral gavage with 0, 1.0, 2.0, and 4.0 mg deltamethrin/kg from day 1 of pregnancy to day 21 of lactation. Maternal and reproductive outcome data and male sexual development landmarks were assessed. Fertility, sexual behavior, and a large number of reproductive endpoints, such as organ weights, sperm evaluations, testosterone concentration, and testicular histology were examined on adult male offsprings. No signs of maternal toxicity were detected at the dose levels tested. Significantly adverse effects were only seen on testicular and epididymal absolute weights and the diameter of seminiferous tubules in the group treated with the highest dose of deltamethrin (4.0 mg/kg). The results indicate that in utero and lactational exposure to deltamethrin may induce subtle changes in reproductive behavior and physiology of male offspring rats at dose levels that do not cause maternal toxicity.

Laboratory Bioassay of Three Doses of Deltamethrin +Triazophos (Deltaphos 10+350 EC) on Field Collected Medium to Large Sized Helicoverpa Sp. Larvae Infesting Gram Pods

Laboratory Bioassay of Three Doses of Deltamethrin +Triazophos (Deltaphos 10+350 EC) on Field Collected Medium to Large Sized Helicoverpa Sp. Larvae Infesting Gram Pods

Partial compensation of the sublethal effect of deltamethrin on the sex pheromonal communication of Trichogramma brassicae

Pyrethroid insecticides are widely used and lead to a sizable environmental pollution that could interfere with the population biology of insects. Trichogramma is a beneficial insect used in biological control and which natural populations contribute to the control of Lepidopterus pests. In this work, we determined the effect of a sublethal dose of deltamethrin on the sex pheromonal communication of Trichogramma. The dose used (LD 0.1) induces no detectable mortality (the theoretical mortality is only one insect over 1000) and can be a good representation of contamination by this insecticide from environmental pollution. The insecticide was shown to have opposite effects on the sex pheromonal communication of Trichogramma, depending on which sex was exposed (Delpuech, J.M., Legallet, B., Terrier, O., Fouillet, P., 1999. Chemosphere 38, 729–739). We show that, when both sexes are simultaneously exposed to the insecticide, this effect is only partially neutralized. The mean response of treated males responding to the sex pheromone from treated females is not significantly different from that of controls, but the kinetics of their response is not the same. When both sexes are treated, the response of males to the sex pheromone is lower at the beginning but their response does not decrease during time contrary to controls and becomes finally higher than that of controls. Therefore, the sublethal effect of deltamethrin in the field can be either advantageous or disadvantageous depending on the difficulty in finding females and their scarcity.

Effect of the synergists piperonyl butoxide and DEF in deltamethrin resistance on strains of Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae)

Synergists are an important research tool in the laboratory to help to determine the mechanisms of resistance involved in a particular population. This kind of investigation has produced valuable results in understanding resistance to pesticides. The ability of these compounds in suppressing deltamethrin resistance on four strains of Rhyzopertha dominica (F.) was evaluated under laboratory conditions. Two susceptible strains, obtained from the eighth generation in laboratory without any selection were tested; other two resistant strains consisted in the fifth deltamethrin selected generation. Each strain was bioassayed on filter paper impregnated with deltamethrin associated with a synergist in different proportions, following the methods recommended by FAO for assessing resistance. The synergists tested were piperonyl butoxide (PBO) and S,S,S-tributyl phosphorotrithioate (DEF), at the following proportions 1:0, 1:5, 1:10 and 1:15 of deltamethrin and the synergist, respectively. Both synergists showed a role in blocking enzymes involved in detoxifying deltamethrin. PBO conferred up to 27 times higher toxicity ratios in the resistant strains than in the susceptible ones. DEF was less effective in reducing the lethal dose of deltamethrin with ratios up to five times.

Mutagenic evaluation of deltamethrin using rodent dominant lethal assay

The dominant lethal test was used to analyse the mutagenic potential of deltamethrin, a synthetic pyrethroid insecticide, in Swiss albino mice. In the treated series, the animals were exposed orally to three different doses (0.36, 0.72 and 1.08 mg/kg body weight) of deltamethrin dissolved in corn oil. Following the treatment, each male of control, as well as of the treated series, was mated with untreated females, every week for a period of 6 weeks. All mated females were sacrificed on the 13th day of separation and their ovaries and uterus were examined. The results revealed that deltamethrin treatment did not impair the mating capacity and fertility of Swiss albino mice. Mutagenic index, pre- and post-implantation losses were assessed. No significant pre-implantation losses were observed either weekly or averagely. Post-implantation losses were observed at medium and high doses of deltamethrin. A slight increase in dominant lethal mutation rate was observed by increasing doses of deltamethrin in early weeks but decreased in later weeks, so an apparent dose response was not observed.

Circadian dynamics of locomotor activity and deltamethrin susceptibility in the pine weevil,Hylobius abietis

Rhythmic locomotor activity and daily susceptibility to deltamethrin were tested in the pine weevil,Hylobius abietis (L.) (Coleoptera, Curculionidae), a pest of young conifer plants. In constant darkness, beetles revealed a free-running circadian pattern of locomotor activity (average period 22h : 20min). Under long photoperiod, L:D 18:6, entrainment of motor activity was observed. In the entrained population of the weevils, a peak of locomotor activity occurred at about the beginning of the dark phase, and the minimum occurred in the middle of the light phase. Fluctuations of susceptibility to a standard dose of deltamethrin (0.5 μg/g body weight) varied across the day, and were inversely correlated to the changes in locomotor activity. The importance of considering the daily organization of insect biology in studying insect resistance to pesticides is re-emphasized.

Modifications of the sex pheromonal communication of Trichogramm4 brassicae by a sublethal dose of deltamethrin

Pyrethroid insecticides, by their intensive use and their persistence that can exceed 3 months, largely contribute to the environmental pollution. In this work, we determined the effects of a very low dose of deltamethrin on the sex pheromonal communication of Trichogramma brassicae. The dose used was a dose that would theoretically kill one insect over 1000 (an LD 0.1). We found that this dose slightly but very significantly increased the arrestment behavior of treated males responding to the female pheromone. On the other hand when females were exposed to the same dose of insecticide, the response of males to their pheromone was very significantly decreased. In Trichogramma, like in other insects, sex pheromonal communication probably involves nervous transmissions both for the reception and the emission of the pheromone. Then, the sublethal effects of deltamethrin, observed in this work, are certainly due to multiple actions of this insecticide on nervous transmissions. Trichogramma is a beneficial insect that contributes to the control of pest populations of moths. Actions of this insecticide at a dose that can correspond to environmental pollution could be a real threat to the equilibrium of these populations.

Seasonal variations in susceptibility of Apis mellifera to the synergistic action of prochloraz and deltamethrin

AbstractThe synergistic action of prochloraz and deltamethrin was investigated in summerand winter bees. Prochloraz and deltamethrin were used at sublethal doses that did not induce any significant mortality. Bees were treated with different doses of deltamethrin, either alone or in combination with prochloraz, at the constant field rate of 25 g/ha. In summer bees, the combination of prochloraz and deltamethrin at 125 mg/ha triggered a synergy that produced approx. 63 ± 5% mortality (corrected) after 24 h. At 62.5 mg/ha, deltamethrin still acted in synergy with prochloraz by inducing about 32.5 ± 3.5% mortality (corrected) after 24 h. The field rate of 31.25 mg/ha was the lowest dose at which deltamethrin acted in synergy with prochloraz in summer bees. In winter bees, no synergy occurred between prochloraz and deltamethrin at doses of 125 and 250 mg/ha. The deltamethrin dose had to be increased to 500 mg/ha to observe a synergy that produced only 47 ± 11.7% mortality (corrected) after 24 h. Considering the deltamethrin doses at which synergy occurred, summer bees appeared to be approximately eightfold more susceptible than winter bees to the synergistic action of prochloraz and deltamethrin.

Sublethal effects of deltamethrin and propoxur on longevity and reproduction of German cockroaches, Blattella germanica

AbstractThe effects of sublethal doses of deltamethrin and propoxur, applied topically at LD10, LD30 and LD50 on German cockroaches, were studied by reciprocal crossing. Male and female longevities decreased curvilinearly with increasing sublethal doses of deltamethrin, and decreased linearly with increasing sublethal doses of propoxur. Fecundity of females treated with deltamethrin and propoxur was reduced with increasing sublethal doses of both insecticides. Oothecal production, oothecal hatchability and nymphal production also declined with increasing doses of deltamethrin and propoxur. Preoviposition and incubation periods were not affected by sublethal doses of deltamethrin and propoxur, although some significant differences were observed at certain oothecal numbers. Two‐way analysis of variance indicated that only treated females showed an effect on oothecal production while oothecal hatch and nymphal production were governed by both treated females and males. Insecticide susceptibility tests on the progeny of parents treated with sublethal doses demonstrated that these doses did not increase insecticidal tolerance in the F1 generation.

In vitro genotoxic effects of the insecticide deltamethrin in human peripheral blood leukocytes: DNA damage (‘comet’ assay) in relation to the induction of sister-chromatid exchanges and micronuclei

Deltamethrin, a synthetic dibromo-pyrethroid insecticide, is extensively used in agriculture, forestry and in household products because of its high activity against a broad spectrum of insect pests (both adults and larvae), its low animal toxicity and its lack of persistence in the environment. Data on the genotoxicity and carcinogenicity of deltamethrin are rather controversial, depending on the genetic system or the assay used. The aim of this study was to further evaluate the potential genotoxic activity of deltamethrin. The in vitro genotoxicity of deltamethrin has been evaluated by assessing the ability of the insecticide to damage DNA (as evaluated using the single-cell microgel-electrophoresis or ‘comet’ assay) or induce sister-chromatid exchanges (SCE) and micronuclei (MN) in human peripheral blood leukocytes. All treatments were conducted with and without the presence of an external bioactivation source (±S9mix). The results indicate that deltamethrin, in the presence of metabolic activation (+S9mix), is able to induce DNA damage (double- and single-strand breaks, alkali-labile sites and open excision repair sites) as revealed by the increasing tail moment values observed with increasing doses. The frequency of SCE and MN were not statistically increased in deltamethrin-treated cells as compared to controls, both with and without S9mix. However, lower deltamethrin doses were tested, as compared to ‘comet’ assay, because of cytotoxicity.