Comparing the egg ultrastructure of three Psorophora ferox (Diptera: Culicidae) populations / Comparação da ultraestrutura de ovos de três populações de Psorophora ferox (Diptera: Culicidae)

Abstract Characterising the external morphology of mosquito eggs is important, since it facilitates the identification of material from breeding sites and contributes to the understanding of species biology and group systematics. Therefore, was to compare eggs from different Psorophora ferox populations using scanning electron microscopy (SEM). Eggs were obtained from adult female of Ps. ferox collected in the Poços das Antas Biological Reserve (Reserva Biológica de Poços das Antas, Rio de Janeiro, Brazil). From each female, one portion of eggs (n = 5) was reared for identification purposes, and the second portion (n = 10) was examined using SEM for morphometric analysis. The egg morphology was then compared to that of eggs from Ps. ferox populations in Florida (USA) and Arena (Trinidad). The exochorion ornamentation of the populations differs considerably in the morphology of the tubercles of the chorionic cells, external chorionic reticulum, micropylar collar, and micropyle.

Resumo Caracterização da morfologia externa dos ovos do mosquito é importante, uma vez que facilita a identificação de materiais a partir de locais de reprodução e contribui para a compreensão da biologia das espécies e sistemática do grupo. O objetivo do presente estudo foi comparar os ovos de diferentes populações Psorophora ferox usando MEV. Os ovos foram obtidos a partir de fêmeas de Ps. ferox que foram coletadas na Reserva Biológica de Poço das Antas (Reserva Biológica de Poço das Antas, Rio de Janeiro, Brasil). A partir de cada fêmea, uma parte dos ovos (n = 5) foi criado para fins de identificação, e uma segunda parte (n = 10) foi examinado usando MEV para análise morfométrica. Foi então comparada a morfologia dos ovos de populações de Ps.ferox da Flórida (EUA) e Arena (Trinidad). A ornamentação do exocório das populações difere consideravelmente na morfologia dos tubérculos das células coriônicas, retículo coriônico externo, colar micropilar e micrópila.

Latent class analysis of attention and white matter correlation in children with attention-deficit/hyperactivity disorder

This study aimed to explore attentional patterns among children with inattentive attention-deficit/hyperactivity disorder (ADHD-I) and children with typical development (TD), using a latent class analysis (LCA). Patterns of brain connectivity were also explored. The sample comprised 29 ADHD-I and 29 TD matched children. An LCA was conducted to reclassify subjects according to their attentional performance, considering cognitive measures of attention and behavioral symptoms, regardless of group of origin. The new clusters were then compared in respect to brain white matter measurements (extracted from diffusion tensor imaging). Participants were rearranged in 2 new latent classes, according to their performance in an attention task and the results of behavioral scales, resulting in groups with more homogeneous attentional profiles. A comparison of the 2 new classes using the white matter measurements revealed increased fractional anisotropy in the left inferior fronto-occipital fasciculus and left inferior longitudinal fasciculus for the class composed by participants with a higher risk of attentional problems. The findings indicated that it was possible to observe variability regarding neuropsychological profile, accompanied by underpinning neurobiological differences, even among individuals with the same disorder subtype - inattentive ADHD. This specific data-driven clustering analysis may help to enhance understanding of the pathophysiology of the disorder's phenotypes.

Comparing the egg ultrastructure of three Psorophora ferox (Diptera: Culicidae) populations

Abstract Characterising the external morphology of mosquito eggs is important, since it facilitates the identification of material from breeding sites and contributes to the understanding of species biology and group systematics. Therefore, was to compare eggs from different Psorophora ferox populations using scanning electron microscopy (SEM). Eggs were obtained from adult female of Ps. ferox collected in the Poços das Antas Biological Reserve (Reserva Biológica de Poços das Antas, Rio de Janeiro, Brazil). From each female, one portion of eggs (n = 5) was reared for identification purposes, and the second portion (n = 10) was examined using SEM for morphometric analysis. The egg morphology was then compared to that of eggs from Ps. ferox populations in Florida (USA) and Arena (Trinidad). The exochorion ornamentation of the populations differs considerably in the morphology of the tubercles of the chorionic cells, external chorionic reticulum, micropylar collar, and micropyle.

Resumo Caracterização da morfologia externa dos ovos do mosquito é importante, uma vez que facilita a identificação de materiais a partir de locais de reprodução e contribui para a compreensão da biologia das espécies e sistemática do grupo. O objetivo do presente estudo foi comparar os ovos de diferentes populações Psorophora ferox usando MEV. Os ovos foram obtidos a partir de fêmeas de Ps. ferox que foram coletadas na Reserva Biológica de Poço das Antas (Reserva Biológica de Poço das Antas, Rio de Janeiro, Brasil). A partir de cada fêmea, uma parte dos ovos (n = 5) foi criado para fins de identificação, e uma segunda parte (n = 10) foi examinado usando MEV para análise morfométrica. Foi então comparada a morfologia dos ovos de populações de Ps.ferox da Flórida (EUA) e Arena (Trinidad). A ornamentação do exocório das populações difere consideravelmente na morfologia dos tubérculos das células coriônicas, retículo coriônico externo, colar micropilar e micrópila.

Montelukast reduces seizures in pentylenetetrazol-kindled mice

Cysteinyl leukotrienes (CysLTs) have been implicated in seizures and kindling; however, the effect of CysLT receptor antagonists on seizure frequency in kindled animals and changes in CysLT receptor expression after pentylenetetrazol (PTZ)-induced kindling have not been investigated. In this study, we evaluated whether the CysLT1 inverse agonist montelukast, and a classical anticonvulsant, phenobarbital, were able to reduce seizures in PTZ-kindled mice and alter CysLT receptor expression. Montelukast (10 mg/kg, sc) and phenobarbital (20 mg/kg, sc) increased the latency to generalized seizures in kindled mice. Montelukast increased CysLT1 immunoreactivity only in non-kindled, PTZ-challenged mice. Interestingly, PTZ challenge decreased CysLT2 immunoreactivity only in kindled mice. CysLT1 antagonists appear to emerge as a promising adjunctive treatment for refractory seizures. Nevertheless, additional studies are necessary to evaluate the clinical implications of this research.

Maternal serum progesterone, estradiol and estriol levels in successful dinoprostone-induced labor

Hormone-mediated quiescence involves the maintenance of a decreased inflammatory responsiveness. However, no study has investigated whether labor induction with prostanoids is associated with changes in the levels of maternal serum hormones. The objective of this study was to determine whether labor induction with dinoprostone is associated with changes in maternal serum progesterone, estradiol, and estriol levels. Blood samples were obtained from 81 pregnant women at term. Sixteen patients had vaginal birth after spontaneous labor, 12 required cesarean section after spontaneous labor and 16 underwent elective cesarean. Thirty-seven patients had labor induction with dinoprostone. Eligible patients received a vaginal insert of dinoprostone (10 mg) and were followed until delivery. Serum progesterone (P4), estradiol (E2) and estriol (E3) levels and changes in P4/E2, P4/E3 and E3/E2 ratios were monitored from admission to immediately before birth, and the association of these measures with the resulting clinical classification outcome (route of delivery and induction responsiveness) was assessed. Progesterone levels decreased from admission to birth in patients who underwent successful labor induction with dinoprostone [vaginal and cesarean birth after induced labor: 23% (P < 0.001) and 18% (P < 0.025) decrease, respectively], but not in those whose induction failed (6.4% decrease, P > 0.05). Estriol and estradiol levels, P4/E2, P4/E3 and E3/E2 ratios did not differ between groups. Successful dinoprostone-induced labor was associated with reduced maternal progesterone levels from induction to birth. While a causal relationship between progesterone decrease and effective dinoprostone-induced labor cannot be established, it is tempting to propose that dinoprostone may contribute to progesterone withdrawal and favor labor induction in humans.

Ocorrência de Aeromonas sp. e microrganismos psicrotróficos e estimativa do prazo de validade comercial de filé de pintado (Pseudoplatystoma coruscans) mantidos sob refrigeração / Occurrence of Aeromonas sp. and psychrotrophic microorganisms and estimate the shelf life of "pintado" (Pseudoplatystoma coruscans) fillets kept under refrigeration

Verificou-se a ocorrência de bactérias do gênero Aeromonas e estimou-se o prazo de validade comercial de filés de pintado (Pseudoplatystoma coruscans) com pele, durante estocagem em refrigeração por meio da quantificação de microrganismos heterotróficos aeróbios psicrotróficos e análises físico-químicas para determinação do pH e detecção de amônia e gás sulfídrico. Foram utilizadas 45 amostras de filé de pintado, com aproximadamente 100 gramas cada, embaladas individualmente em polietileno de alta densidade e armazenadas em câmara frigorífica entre 0ºC e 3ºC. A cada dois a três dias de estocagem, três unidades de filés foram submetidas a análises microbiológicas e físico-químicas, totalizando 15 análises durante o período de estocagem. As contagens de Aeromonas sp. e microrganismos heterotróficos aeróbios psicrotróficos variaram de 1,89 a 9,47logUFC/g e 0 a 6,54logUFC/g, respectivamente. A variação do pH foi de 6,20 a 6,97, e as análises de amônia e gás sulfídrico foram negativas durante todo o período. O pH dos filés de pintado atingiu o limite máximo de 6,4 aos 23 dias de estocagem, e estimou-se o seu prazo de validade comercial.

This word studied the occurrence of bacteria from genus Aeromonas and estimate the shelf life of "pintado" fish fillets (Pseudoplatystoma coruscans), during cold storage, through the quantification of psychrotrophic aerobic microorganisms, physical and chemical analyses for presence of ammonia and gas sulphide (H2S) and pH as used in 45 samples of "pintado" fillets with approximately 100 grams each, individually packed in high density polyethylene and stored in cold storage (0ºC to 3ºC). Every 2-3 days of storage, 3 units of fillets were subjected to microbiological and physicochemical analysis for a total of 15 days during the storage period. The Aeromonas sp. and psychrotrophic microorganisms count varied from 1.89 to 9.47logCFU/g and 0 to 6.54logCFU/g, respectively. The pH variation was from 6.20 to 6.97 and ammonia and H2S analyses were negative during the whole period. According under Brazilian legislation (Brazil, 1981) estimated the commercial shelf life of "pintado" fillets being 23 days when the pH reached a value of 6.4. The pH of the "pintado" fillets reached the maximum limit of 6.4 at 23 days of storage, being its estimated commercial shelf life.

Antipyretic and antioxidant activities of 5-trifluoromethyl-4,5-dihydro-1H-pyrazoles in rats

The objective of this study was to determine the effect of eight 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-carboxyamidepyrazoles (TFDPs) on rat body temperature and baker’s yeast-induced fever. TFDPs or vehicle (5 percent Tween 80 in 0.9 percent NaCl, 5 mL/kg) were injected subcutaneously and rectal temperature was measured as a function of time in 28-day-old male Wistar rats (N = 5-12 per group). Antipyretic activity was determined in feverish animals injected with baker’s yeast (Saccharomyces cerevisiae suspension, 0.135 mg/kg, 10 mL/kg, ip). 3-Ethyl- and 3-propyl-TFDP (140 and 200 μmol/kg, respectively, 4 h after yeast injection) attenuated baker’s yeast-induced fever by 61 and 82 percent, respectively. These two effective antipyretics were selected for subsequent analysis of putative mechanisms of action. We then determined the effects on cyclooxygenase-1 and -2 (COX-1 and COX-2) activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) oxidation in vitro, on tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels and on leukocyte counts in the washes of peritoneal cavities of rats injected with baker’s yeast. While 3-ethyl- and 3-propyl-TFDP did not reduce baker’s yeast-induced increases of IL-1β or TNF-α levels, 3-ethyl-TFDP caused a 42 percent reduction in peritoneal leukocyte count. 3-Ethyl- and 3-propyl-TFDP did not alter COX-1 or COX-2 activities in vitro, but presented antioxidant activity in the DPPH assay with an IC50 of 39 mM (25-62) and 163 mM (136-196), respectively. The data indicate that mechanisms of action of these two novel antipyretic pyrazole derivatives do not involve the classic inhibition of the COX pathway or pyrogenic cytokine release.

Laboratory evaluation of the effects of triflumuron on the development of Rhodnius prolixus nymph

Studies were carried out to evaluate the efficacy of the growth regulator, triflumuron (TFM) (Starycide® sc 480 Bayer), for disrupting the development of Rhodnius prolixus fifth-instar nymph by oral, topical or continuous treatment. All treatments were able to induce high levels of mortality, delay development and molt inhibition. Oral treatment induced molt inhibition in all insects that survived at doses of 0.25, 0.50 and 5.0 mg/mL of a blood meal. The highest levels of both mortality in 24 h and molt inhibition were always observed after topical treatment. The lowest doses needed to obtain considerable biological effects were always observed after continuous treatment. In this way, the highest levels of mortality within 30 days were detected after continuous treatment, which also induced an extended inter-molting period, a lower number of over-aged nymphs and the highest level of molting in nymphs that survived. Moreover, the effects of TFM on insects were often displayed in a dose response manner. These results indicate that TFM acts as a potent growth inhibitor of R. prolixus nymphs and has the potential to be used in integrated vector control programs against hematophagous triatomine species.

A pyrazolyl-thiazole derivative causes antinociception in mice

The present study investigates the antinociceptive effect of the pyrazolyl-thiazole derivative 2-(5-trichloromethyl-5-hydroxy-3-phenyl-4,5-dihydro-1 H-pyrazol-1-yl)-4-(4-bromophenyl)-5-methylthiazole (B50) in mice. Male albino Swiss mice (30-40 g) were used in the acetic acid-induced abdominal writhes and tail-immersion tests. B50 caused dose-dependent antinociception (8, 23 and 80 µmol/kg, sc) in the acetic acid writhing assay (number of writhes: vehicle: 27.69 ± 6.15; B50 (8 µmol/kg): 16.92 ± 3.84; B50 (23 µmol/kg): 13.85 ± 3.84; B50 (80 µmol/kg): 9.54 ± 3.08; data are reported as means ± SEM for 9 animals per group). On the other hand, B50 did not cause antinociception in the tail immersion assay. Naloxone (2.75 µmol/kg, sc) prevented B50-induced antinociception (number of writhes: vehicle-saline: 31.11 ± 3.15; vehicle-naloxone: 27.41 ± 3.70; B50 (80 µmol/kg)-saline: 8.70 ± 3.33; B50 (80 µmol/kg)-naloxone: 31.84 ± 4.26; morphine-saline: 2.04 ± 3.52; morphine-naloxone: 21.11 ± 4.26; 8-9 animals per group). The removal of the methyl group of the thiazole ring of B50 or substitution of the bromo substituent with the methyl at position 4 of the phenyl group, which is attached to the thiazole ring of B50, resulted in loss of activity, suggesting that these substituents are important for antinociceptive activity. B50 had no effect on spontaneous locomotion or rotarod performance, indicating that the antinociceptive effect of B50 is not related to nonspecific motor effects. The antinociceptive profile of B50 seems to be closer to nonsteroidal anti-inflammatory drugs than to classic opioid agents, since it had no analgesic effect in a thermally motivated test.

Comportamento térmico de alguns fármacos e medicamentos / Thermal studies of some pharmaceutical drugs

A técnica de análise térmica apresenta aplicações em diversos ramos da ciência, entre eles a indústria farmacêutica, a qual pode utilizá-la para caracterização e estudo das matérias primas e produtos finais. Os compostos farmacêuticos apresentam diferentes formas morfológicas ou estruturais,que afetam diretamente na sua estabilidade, ação e liberação. O desenvolvimento e fabricação de medicamentos requerem intenso cuidado devido a pureza, qualidade e estabilidade dos componentes. Um dos itens para se obter uma formulação estável e efetiva depende dos cuidados na escolha dos excipientes utilizados, onde uma de suas propriedades é a de interferir na biodisponibilidade e proteção do fármaco frente a degradação. Neste trabalho foram utilizadas técnicas de análise térmica (TG/DTG/DSC/DTA) e a espectroscopia Raman para estudar possíveis interações entre o fármaco e seus excipientes. Foram selecionados para o estudo os medicamentos Aspirina® e AAS®, comparados com o seu princípio ativo ácido acetil salicílico. As amostras não sofreram pré tratamento e foram analisadas como adquiridas no mercado. Os resultados obtidos através das técnicas de análise térmica evidenciaram uma possível interação entre os diferentes excipientes utilizados e o princípio ativo. Os espectros Raman corroboram com os resultados obtidos das análises térmicas dos medicamentos. Através dos resultados obtidos concluímos que as diferentes composições existentes na formulação dos medicamentos podem promover mudanças em suas propriedades físicas e consequentemente na sua atividade biológica.

Effect of blood components, abdominal distension, and ecdysone therapy on the ultrastructural organization of posterior midgut epithelial cells and perimicrovillar membranes in Rhodnius prolixus

The effects of blood components, nerve-cord severance, and ecdysone therapy on the posterior midgut epithelial cells of 5th-instar Rhodnius prolixus nymphs 10 days after feeding were analyzed by transmission electron microscopy. Cutting the nerve-cord of the blood-fed insects partially reduced the development of microvilli and perimicrovillar membranes (PMM), and produced large vacuoles and small electrondense granules; insects fed on Ringer's saline diet exhibited well developed microvilli and low PMM production; swolled rough endoplasmatic reticulum and electrondense granules; Ringer's saline meal with ecdysone led to PMM development, glycogen particles, and several mitochondria in the cytoplasm; epithelial cells of the insects fed on Ringer's saline meal whose nerve-cord was severed showed heterogeneously distributed microvilli with reduced PMM production and a great quantity of mitochondria and glycogen in the cytoplasm; well developed microvilli and PMM were observed in nerve-cord severed insects fed on Ringer's saline meal with ecdysone; Ringer's saline diet containing hemoglobin recovered the release of PMM; and insects fed on human plasma showed slightly reduced PMM production, although the addition of ecdysone in the plasma led to a normal midgut ultrastructural organization. We suggest that the full development of microvilli and PMM in the epithelial cells depends on the abdominal distension in addition to ingestion of hemoglobin, and the release of ecdysone.

Antinociceptive effect of novel pyrazolines in mice

The antinociceptive effect of six novel synthetic pyrazolines (3-ethoxymethyl-5-ethoxycarbonyl-1H-pyrazole (Pz 1) and its corresponding 1-substituted methyl (Pz 2) and phenyl (Pz 3) analogues, and 3-(1-ethoxyethyl)-5-ethoxycarbonyl-1H-pyrazole (Pz 4) and its corresponding 1-substituted methyl (Pz 5) and phenyl (Pz 6) analogues) was evaluated by the tail immersion test in adult male albino mice. The animals (N = 11-12 in each group) received vehicle (5 percent Tween 80, 10 ml/kg, sc) or 1.5 mmol/kg of each of the pyrazolines (Pz 1-Pz 6), sc. Fifteen, thirty and sixty minutes after drug administration, the mice were subjected to the tail immersion test. Thirty minutes after drug administration Pz 2 and Pz 3 increased tail withdrawal latency (vehicle = 3.4 ± 0.2; Pz 2 = 5.2 ± 0.4; Pz 3 = 5.9 ± 0.4 s; mean ± SEM), whereas the other pyrazolines did not present antinociceptive activity. Dose-effect curves (0.15 to 1.5 mmol/kg) were constructed for the bioactive pyrazolines. Pz 2 (1.5 mmol/kg, sc) impaired motor coordination in the rotarod and increased immobility in the open-field test. Pz 3 did not alter rotarod performance and spontaneous locomotion, but increased immobility in the open field at the dose of 1.5 mmol/kg. The involvement of opioid mechanisms in the pyrazoline-induced antinociception was investigated by pretreating the animals with naloxone (2.75 µmol/kg, sc). Naloxone prevented Pz 3- but not Pz 2-induced antinociception. Moreover, naloxone pretreatment did not alter Pz 3-induced immobility. We conclude that Pz 3-induced antinociception involves opioid mechanisms but this is not the case for Pz 2.

Antinociceptive effects of Cremophor EL orally administered to mice

Surfactants are frequently used to improve solubilization of lipophilic drugs. Cremophor EL (CrEL) is a polyoxyethylated castor oil surfactant used to solubilize water-insoluble drugs such as anesthetic, antineoplastic, immunosuppressive and analgesic drugs, vitamins and new synthetic compounds, including potential analgesics. The antinociceptive effect of CrEL (3.2, 6.4 and 10.6 g/kg, in 10 ml/kg body weight, by gavage) on the abdominal writhing response induced by intraperitoneal administration of acetic acid (0.8 percent, 10 ml/kg body weight) and on the tail immersion test was investigated in mice. Control animals received castor oil (10 ml/kg body weight) or saline (0.9 percent NaCl, 10 ml/kg body weight). CrEL reduced nociception in a dose-dependent manner in both tests. At 10.6 g/kg, CrEL caused antinociception similar to that induced by dipyrone (300 mg/kg, by gavage) in the abdominal writhing test, and antinociception similar to that induced by morphine (20 mg/kg, by gavage) in the tail immersion test. The effect of castor oil was similar to that of saline in both assays. These data indicate that the appropriate controls should be used when evaluating the effects of potential antinociceptive agents dissolved in CrEL

Influence of the test situation on pup retrieval behavior of normal and undernourished lactating rats

Undernutrition of dams and pups disrupts the retrieval efficiency of mothers. However, if the mothers are assessed in their home cages, they spend more time with their litters. In the present study the effect of test conditions on pup retrieval behavior of mothers receiving a 25 percent (well-nourished group) and 8 percent casein diet (undernourished group) was examined. In agreement with previous studies, undernourished mothers spent more time with their litters than well-nourished dams as lactation proceeded. Pup retrieval behavior varied with test conditions. In the first experiment, the maternal behavior of dams was assessed by the standard procedure (pups were separated from their mother and scattered over the floor of the home cage). The mother was then returned and the number of retrieved pups was recorded. From day 3 to 8, the retrieval efficiency of undernourished dams decreased, while the retrieval efficiency of well-nourished mothers did not vary. In the second experiment, mothers were subjected to a single retrieval test (on day 9 of lactation) using the procedure described for experiment 1. No difference between well-nourished and undernourished mothers was observed. In the third experiment, seven-day-old pups were separated from the mothers and returned individually to a clean home cage. Dietary treatment did not affect the retrieval efficiency. However, undernourished dams reconstructed the nest more slowly than did well-nourished dams. Taken together, these results suggest that pup retrieval behavior of the undernourished mother is not impaired by dietary restriction when the maternal environment is disturbed minimally

Novas atividades biológicas em antigos metabólitos: ácido oleanólico e eugenol de Eugenia caryophyllata

Ácido oleanólico apresenta no barbeiro Rhodnius prolixus, vetor da doença de Chagas, toxicidade dosedependente e drástica inibição da muda nas doses de 1, 10 e 100 mg/ml. Eugenol induz uma letargia que persiste por vários dias, apresenta forte fagorrepelência, toxicidade média e inibição total da muda nas doses de 10 e 100 mg/ml.

Anxiolytic-like effects of 4-phenyl-2-trichloromethyl-3H-1, 5-benzodiazepine hydrogen sulfate in mice

The pharmacological effects of 4-phenyl-2-trichloromethyl-3H-1,5-benzodiazepine hydrogen sulfate (PTMB), a novel synthetic benzodiazepine, were examined in mice. In the elevated plus-maze test of anxiety, 0.3-1 mg/kg diazepam ip (F(3,53) = 3.78; P<0.05) and 1-10 mg/kg PTMB ip increased (F(5,98) = 3.26; P<0.01), whereas 2 mg/kg picrotoxin ip decreased (F(3,59) = 8.32; P<0.001) the proportion of time spent in the open arms, consistent with an anxiolytic action of both benzodiazepines, and an anxiogenic role for picrotoxin. In the holeboard, 1.0 mg/kg diazepam ip increased (F(3,54) = 2.78; P<0.05) and 2 mg/kg picrotoxin ip decreased (F(3,59) = 4.69; P<0.01) locomotor activity. Rotarod assessment revealed that 1 mg/kg diazepam ip and 3, 10 and 30 mg/kg PTMB ip produced significant motor incoordination compared to vehicle control (F(4,70) = 7.6; P<0.001). These data suggest that the recently synthesized PTMB compound possesses anxiolytic activity and produces motor incoordination similar to those observed with diazepam

Effect of lead acetate on neurobehavioral development of rats

We investigated the effects of lead exposure during the pre- and postnatal period on the neurobehavioral development of female Wistar rats (70-75 days of age, 120-150 g) using a protocol of lead intoxication that does not affect weight gain. Wistar rats were submitted to lead acetate intoxication by giving their dams 1.0 mM lead acetate. Control dams received deionized water. Growth and neuromotor development were assessed by monitoring daily the following parameters in 20 litters: body weight, ear unfolding, incisor eruption, eye opening, righting, palmar grasp, negative geotaxis, cliff avoidance and startle reflex. Spontaneous alternation was assessed on potnatal day 17 using a T maze. The animals'ability to equilibrate on a beaker rim was measured on postnatal day 19. Lead intoxication was confirmed by measuring renal, hepatic and cerebral lead concentration in dams and litters. Lead treatment hastened the day of appearance of the following parameters: eye opening (control: 13.5 + 0.6, N= 88; lead: 12.9 + 0.6, N=72; P<0.05), startle reflex (control: 13.0 + 0.8, N= 88; lead: 12.0 + 0.7, N=72; P<0.05) and negative geotaxis. On the other hand, spontaneous alternation performance was hindered in lead-exposed animals (control: 37.6 + 19.7; lead: 57.5 + 28.3 percent of alternating animals; P<0.05). These results suggest that lead exposure without concomitant undernutrition alters rat development, affecting specific subsets of motor skills.

Antinociceptive effect of purine nucleotides

The antinociceptive effect of purine nucleotides administered systemically (sc) was determined using the formalin and writhing tests in adult male albino mice. The mechanisms underlying nucleotide-induced antinociception were investigated by preinjecting the animals (sc) with specific antagonists for opioid (naloxone, 1 mg/kg), purinergic P1 (caffeine, 5, 10 or 30 mg/kg); theophylline, 10 mg/kg) or purinergic P2 receptors (suramin, 100 mg/kg; Coomassie blue, 30-300 mg/kg; quinidine, 10 mg/kg). Adenosine, adenosine monophosphate (AMP), diphosphate (ADP) and triphosphate (ATP) caused a reduction in the number of writhes and in the time of licking the formalin-injected paw. Naloxone had no effect on adenosine- or adenine nucleotide-induced antinociception. Caffeine (30 mg/kg) and theophylline (10 mg/kg) reversed the antinociceptive action of adenosine and adenine nucleotide derivatives in both tests. P2 antagonists did not reverse adenine nucleotide-induced antinociception. These results suggest that the antinociceptive effect of adenine nucleotides is mediated by adenosine.