Perinatal N(G)-Nitro-L-arginine methyl ester administration decreases anxiety- and depression-like behaviors in adult mice

ABSTRACT Objective: We hypothesized that perinatal manipulations of the nitrergic system would affect adult animal behaviors. Methods: We tested this hypothesis by perinatally administering N(G)-Nitro-L-arginine methyl ester (L-NAME), a non-specific antagonist of nitric oxide synthase for 15 days and assessed anxiety- and depression-like behaviors in adult mice. At 70 days of age, the mice were subjected to a battery of tests consisting of the open-field, light/dark box, forced swim, and tail-flick tests. The tests were performed at two-day intervals, and the order of the tests within the battery was determined according to the progressive invasiveness degree. Results: L-NAME-treated animals exhibited decreased anxiety-like behavior in the light/dark box and open field tests, with no change in locomotor activity. Additionally, they demonstrated decreased depression-like behavior in the forced swim test and no change in pain perception in the tail-flick test. Conclusion: The nitrergic system is possibly involved in neural circuitry development that regulates behaviors since blocking perinatal nitric oxide production decreases anxiety- and depression-like behaviors in adult mice.

Does the combination of resistance training and stretching increase cardiac overload?

OBJECTIVES: To compare the effects of combinations of resistance training (RT) and static stretching (SS) on heart rate (HR), systolic pressure (SBP), diastolic pressure (DBP), rate pressure product (RPP), oxygen saturation (SpO2), rating of perceived effort (RPE), and heart rate variability (HRV) in men. METHODS: Twelve normotensive healthy men participated in four protocols: a) SS+RT, b) RT+SS, c) RT, and d) SS. Variables were measured before, immediately after, and 15, 30, and 45 min after the sessions. RESULTS: The combination of SS and RT increased (p<0.001) HR when compared to the effects of the noncombined protocols (from 2.38 to 11.02%), and this result indicated metabolic compensation. Regarding DBP, there were differences (p<0.001) between the RT and SS groups (53.93±8.59 vs. 67.00±7.01 mmHg). SS has been shown to be able to reduce (p<0.001) SpO2 (4.67%) due to the occlusion caused by a reduction in the caliber of the blood vessels during SS compared to during rest. The increase in RPP (6.88% between RT and SS+RT) along with the HR results indicated higher metabolic stress than that reflected by the RPE (combined protocols increased RPE from 21.63 to 43.25%). The HRV analysis confirmed these results, showing increases (p<0.01) in the LF index between the combined and noncombined protocols. Compared to the effect of RT, the combination of SS and RT promoted a vagal suppression root mean square of the successive differences (RMSSD) index (from 9.51 to 21.52%) between the RT and SS+RT groups (p<0.01) and between the RT and RT+SS groups (p<0.001). CONCLUSION: Static stretching increases cardiac overload and RPE, reducing oxygen supply, especially when performed in combination with RT.

Novel immunoassay for TSH measurement in rats

ABSTRACT Measuring thyroid hormones is an important aspect for the study of metabolism and for monitoring diseases in both human and animal models. The traditional method for hormone measurement in rats is the radioimmunoassay (RIA). However, the RIA is associated with some practical disadvantages, including the use of radioactive material, the need for specialized equipment and expert staff, the short shelf-life of kits according to the half-life of the radioisotope and high costs. The objective of this study was to develop a new cost-effective method for measuring TSH levels in rats that avoids the use of radioactive material. We developed an in-house competitive immunoassay using a reference standard, polyclonal antibody produced in rabbits and biotinylated antigen. This method was tested in 64 Wistar rats that were divided into a control group (n = 41) and a group with hypothyroidism (n = 23). Our assay demonstrated an analytical sensitivity of 0.24 ng/mL (n = 12) and an intra-assay coefficient of variation (CV) of 8.9% for sera with TSH levels of 1.5 ng/mL and 13.2% for sera with TSH levels of 17.5 ng/mL (n = 14). The inter-assay CV was 13.5% for sera with TSH levels of 1.4 ng/mL and 14.5% for TSH levels of 18.2 ng/mL (n = 5). The analysis of mean TSH levels in control rats (5.06 ± 0.5701) and hypothyroid rats (51.09 ± 5.136) revealed a statistically significant difference (p < 0.001) between the groups. This method showed good sensitivity, can be automated and is low-cost compared with RIA. Our method offers a viable alternative for TSH measurement in rats.