Antinociception induced by acute oral administration of sweet substance in young and adult rodents: The role of endogenous opioid peptides chemical mediators and mu(1)-opioid receptors

The present work aimed to investigate the effects of acute sucrose treatment on the perception of painful stimuli. Specifically, we sought to determine the involvement of the endogenous opioid peptide-mediated system as well as the role of the mu(1)-opioid receptor in antinociception organisation induced by acute sucrose intake. Nociception was assessed with the tail-flick test in rats (75, 150 and 250 g) of different ages acutely pre-treated with 500 mu L. of a sucrose solution (25, 50, 150 and 250 g/L) or tap water. Young and Adult rats (250 g) showed antinociception after treatment with 50 g/L (during 5 min) and 150 g/L and 250 g/L (during 20 min) sucrose solutions. Surprisingly, this antinociception was more consistent in mature adult rodents than in pups. To evaluate the role of opioid systems, mature adult rodents were pre-treated with different doses (0.25, 1 or 4mg/kg) of the non-selective opioid receptor antagonist naloxone, the selective pi-opioid receptor antagonist naloxonazine or vehicle followed by 250 g/L sucrose solution treatment. Sucrose-induced antinociception was reduced by pre-treatment with both naloxone and naloxonazine. The present findings suggest that sweet substance-induced hypo-analgesia is augmented by increasing sucrose concentrations in young and adult rodents. Acute oral sucrose treatment inhibits pain in laboratory animal by mediating endogenous opioid peptide and mu(1)-opioid receptor actions. (C) 2011 Elsevier Inc. All rights reserved.

Memory-rescuing effects of cannabidiol in an animal model of cognitive impairment relevant to neurodegenerative disorders

Rationale Cannabidiol, the main nonpsychotropic constituent of Cannabis sativa, possesses a large number of pharmacological effects including anticonvulsive, sedative, hypnotic, anxiolytic, antipsychotic, anti-inflammatory, and neuroprotective, as demonstrated in clinical and preclinical studies. Many neurodegenerative disorders involve cognitive deficits, and this has led to interest in whether cannabidiol could be useful in the treatment of memory impairment associated to these diseases. Objectives We used an animal model of cognitive impairment induced by iron overload in order to test the effects of cannabidiol in memory-impaired rats. Methods Rats received vehicle or iron at postnatal days 12-14. At the age of 2 months, they received an acute intraperitoneal injection of vehicle or cannabidiol (5.0 or 10.0 mg/kg) immediately after the training session of the novel object recognition task. In order to investigate the effects of chronic cannabidiol, iron-treated rats received daily intraperitoneal injections of cannabidiol for 14 days. Twenty-four hours after the last injection, they were submitted to object recognition training. Retention tests were performed 24 h after training. Results A single acute injection of cannabidiol at the highest dose was able to recover memory in iron-treated rats. Chronic cannabidiol improved recognition memory in iron-treated rats. Acute or chronic cannabidiol does not affect memory in control rats. Conclusions The present findings provide evidence suggesting the potential use of cannabidiol for the treatment of cognitive decline associated with neurodegenerative disorders. Further studies, including clinical trials, are warranted to determine the usefulness of cannabidiol in humans suffering from neurodegenerative disorders.

N-glycome profiling of Bothrops jararaca newborn and adult venoms

Glycosylation is an important post-translational modification of snake venom proteins and contributes to venom proteome complexity. Many snake venom components are known to be glycosylated, however, very little is known about the carbohydrate structures present in venom glycoproteins. Previous studies showed that the ontogenetic shift in diet, from ectothermic prey in early life to endothermic prey in adulthood, and shift in animal size are associated with changes in the venom proteome of the snake Bothrops jararaca. In this study we explored the composition of the N-glycome released from newborn and adult B. jararaca venom proteins. We used an ion trap mass spectrometer (IT-MS) to disassemble glycan structures based on the use of several pathways of MS (MSn) and demonstrate the presence of some structural isomers in both newborn and adult venom B. jararaca N-glycans. The main N-glycans identified in both venoms are of the hybrid/complex type however some mannose-rich type structures were also detected. The N-glycan composition of newborn and adult venoms did not vary indicating that differences in the utilization of the N-glycosylation motif could be the explanation for the differences in the glycosylation levels indicated by the differential electrophoretic profiles previously reported for B. jararaca newborn and adult venoms. (C) 2011 Elsevier B.V. All rights reserved.

Repeated inhalation of crack-cocaine affects spermatogenesis in young and adult mice

To investigate the effects of repeated crack-cocaine inhalation on spermatogenesis of pubertal and mature Balb/c mice, ten young (Y-ex) and ten adult (A(ex)) Balb/c mice were exposed to the smoke from 5 g of crack with 57.7% of pure cocaine in an inhalation chamber, 5 days/week for 2 months. The young (Y-c) and adult (A(c)) control animals (n = 10) were kept in a specially built and controlled animal house facility. The morphologic analysis of both testes of all animals included the analysis of quantitative and qualitative histologic parameters to assess the effect of crack-cocaine on spermatogenesis and Leydig cells. Apoptosis was determined by immunolabeling with caspase-3 antibodies. Compared to the Y-c animals, Y-ex animals showed a significant reduction in the number of stage VII tubules per testis (p = 0.02), Sertoli cells (p < 0.001) and elongated spermatids (p = 0.001). Comparisons between the Y-ex and A(ex) groups identified a significant reduction in the number of Sertoli cells (p < 0.001) and round spermatids (p < 0.001) in the Y-ex group and a significant increase in apoptotic Leydig cells (p = 0.04) in the A(ex) group. The experimental results indicate that crack-cocaine smoke inhalation induced spermatogenesis disruption in chronically exposed mice, particularly in pubertal mice.

Sperm head morphometry in ejaculates of adult marmosets (Callithrix jacchus): a model for studying sperm subpopulations and among-donor variations

In humans and other mammals, sperm morphology has been considered one of the most important predictive parameters of fertility. The objective was to determine the presence and distribution of sperm head morphometric subpopulations in a nonhuman primate model (Callithrix jacchus), using an objective computer analysis system and principal component analysis (PCA) methods to establish the relationship between the subpopulation distribution observed and among-donor variation. The PCA method revealed a stable number of principal components in all donors studied, that represented more than 85% of the cumulative variance in all cases. After cluster analysis, a variable number (from three to seven) sperm morphometric subpopulations were identified with defined sperm dimensions and shapes. There were differences in the distribution of the sperm morphometric subpopulations (P < 0.001) in all ejaculates among the four donors analyzed. In conclusion, in this study, computerized sperm analysis methods combined with PCA cluster analyses were useful to identify, classify, and characterize various head sperm morphometric subpopulations in nonhuman primates, yielding considerable biological information. In addition, because all individuals were kept in the same conditions, differences in the distribution of these subpopulations were not attributed to external or management factors. Finally, the substantial information derived from subpopulation analyses provided new and relevant biological knowledge which may have a practical use for future studies in human and nonhuman primate ejaculates, including identifying individuals more suitable for assisted reproductive technologies. (c) 2012 Elsevier Inc. All rights reserved.

Genetic vaccine for tuberculosis (pVAXhsp65) primes neonate mice for a strong immune response at the adult stage

Abstract Background Vaccination of neonates is generally difficult due to the immaturity of the immune system and consequent higher susceptibility to tolerance induction. Genetic immunization has been described as an alternative to trigger a stronger immune response in neonates, including significant Th1 polarization. In this investigation we analysed the potential use of a genetic vaccine containing the heat shock protein (hsp65) from Mycobacterium leprae (pVAXhsp65) against tuberculosis (TB) in neonate mice. Aspects as antigen production, genomic integration and immunogenicity were evaluated. Methods Hsp65 message and genomic integration were evaluated by RT-PCR and Southern blot, respectively. Immunogenicity of pVAXhsp65 alone or combined with BCG was analysed by specific induction of antibodies and cytokines, both quantified by ELISA. Results This DNA vaccine was transcribed by muscular cells of neonate mice without integration into the cellular genome. Even though this vaccine was not strongly immunogenic when entirely administered (three doses) during early animal's life, it was not tolerogenic. In addition, pVAXhsp65 and BCG were equally able to prime newborn mice for a strong and mixed immune response (Th1 + Th2) to pVAXhsp65 boosters administered later, at the adult life. Conclusion These results suggest that pVAXhsp65 can be safely used as a priming stimulus in neonate animals in prime-boost similar strategies to control TB. However, priming with BCG or pVAXhsp65, directed the ensuing immune response triggered by an heterologous or homologous booster, to a mixed Th1/Th2 pattern of response. Measures as introduction of IL-12 or GM-CSF genes in the vaccine construct or even IL-4 neutralization, are probably required to increase the priming towards Th1 polarization to ensure control of tuberculosis infection.

Urinary acidifier in diet with high excess base for adult cats

Maintaining the pH of urine in the ideal range (6.2 - 6.4) is of great importance for health promotion in the lower urinary tract of cats. In the economic and standard feed sector this is a major concern, given that the animal urine tends to be alkaline after food consumption of those commercial segments, which predispose to the formation of struvite urolith. Therefore, this study aimed to study the effects of increasing levels of urinary acidifiers (0.0%, 0.3%, 0.6% and 0.9%, on a dry matter base) in feed with high excess base over the acid-basic balance in the organism, apparent digestibility coefficients of nutrients, urinary pH, hydro-electrolyte balance in cats, as well as the adequacy of equations proposed in the literature to estimate the urinary pH. Twenty-four adult cats, males and females were distributed in a completely randomized design, consisting of six animals per treatment. The dry matter content of urine presented a quadratic behavior (p<0,05; y = 9.5863 + 3.2299x + 0.7871x2 R2 = 99,91%), HCO3-, total CO2 and excess blood base during the period in which the animals were fed were high when including 0.9% acidifier compared to 0.6% (p<0.05). In contrast, the use of the additive did not change the urinary pH, blood electrolyte concentration, nutrient digestibility, fecal score, food and water intake (p>0.05). The equations proposed in the literature, which use excess of base in feed to estimate urinary pH, overestimated the pH values found in this study.

Effect of the ketamine/xylazine anesthetic on the auditory brainstem response of adult gerbils

The auditory brainstem response (ABR) is a test widely used to assess the integrity of the brain stem. Although it is considered to be an auditory-evoked potential that is influenced by the physical characteristics of the stimulus, such as rate, polarity and type of stimulus, it may also be influenced by the change in several parameters. The use of anesthetics may adversely influence the value of the ABR wave latency. One of the anesthetics used for e ABR assessment, especially in animal research, is the ketamine/xylazine combination. Our objective was to determine the influence of the ketamine/xylazine anesthetic on the ABR latency values in adult gerbils. The ABRs of 12 adult gerbils injected with the anesthetic were collected on three consecutive days, or a total of six collections, namely: pre-collection and A, B, C, D, and E collections. Before each collection the gerbil was injected with a dose of ketamine (100 mg/kg)/xylazine (4 mg/kg). For the capture of the ABR, 2000 click stimuli were used with rarefaction polarity and 13 stimuli per second, 80 dBnHL intensity and in-ear phones. A statistically significant difference was observed in the latency of the V wave in the ABR of gerbils in the C and D collections compared to the pre-, A and E collections, and no difference was observed between the pre-, A, B, and E collections. We conclude that the use of ketamine/xylazine increases the latency of the V wave of the ABR after several doses injected into adult gerbils; thus clinicians should consider the use of this substance in the assessment of ABR.