THE EFFECT OF DIFFERENT VOLUMES OF ACUTE RESISTANCE EXERCISE ON ELDERLY INDIVIDUALS WITH TREATED HYPERTENSION

Scher, LML, Ferriolli, E, Moriguti, JC, Scher, R, and Lima, NKC. The effect of different volumes of acute resistance exercise on elderly individuals with treated hypertension. J Strength Cond Res 25(4): 1016-1023, 2011-Acute resistance exercise can reduce the blood pressure (BP) of hypertensive subjects. The aim of this study was to evaluate the effect of different volumes of acute low-intensity resistance exercise over the magnitude and the extent of BP changes in treated hypertensive elderly individuals. Sixteen participants (7 men, 9 women), with mean age of 68 6 5 years, performed 3 independent randomized sessions: Control (C: 40 minutes of rest), Exercise 1 (E1: 20 minutes, 1 lap in the circuit), and Exercise 2 (E2: 40 minutes, 2 laps in the circuit) with the intensity of 40% of 1 repetition maximum. Blood pressure was measured before (during 20 minutes) and after each session (every 5 minutes during 60 minutes) using both a mercury sphygmomanometer and a semiautomatic device (Omrom-HEM-431). After that, 24-hour ambulatory blood pressure monitoring was performed (Dyna-MAPA). Blood pressure decreased during the first 60 minutes (systolic: p < 0.01, diastolic: p < 0.05) after all exercise sessions. Only the highest volume session promoted a reduction of mean systolic 24-hour BP and awake BP (p, 0.05) after exercise, with higher diastolic BP during sleep (p, 0.05). Diastolic 24-hour BP and both systolic and diastolic BP during sleep were higher after E1 (p, 0.05). Concluding, acute resistive exercise sessions in a circuit with different volumes reduced BP during the first 60 minutes after exercise in elderly individuals with treated hypertension. However, only the highest volume promoted a reduction of mean 24-hour and awake systolic BP.

Blood and Salivary Oxidative Stress Biomarkers Following an Acute Session of Resistance Exercise in Humans

The aim of the present study was to compare oxidative stress biomarkers determined in blood and saliva before and after acute resistance exercise. 1 week after 1 maximum repetition (1RM) test 11 healthy well-trained males completed a hypertrophy acute session of resistance training including 3 sets of 10 repetitions at 75% of the 1RM, with 90s rest periods between sets. Venous blood and saliva samples were collected before (pre) and 10 min after (post) the resistance training session. A significant (p < 0.05) rise in blood lactate accumulation (pre: 1.6 +/- 0.4 vs. post: 9.5 +/- 2.4) was found post-acute resistance training compared with baseline values. Significant increases (p < 0.05) in TBARS (42%), AOPP (28%), uric acid (27%) and GSH (14%) were detected post-acute resistance training in relation to pre in blood samples. A significant increase (p < 0.05) in uric acid (36%) was found in saliva post-acute resistance training as well as a significant correlation (p < 0.05) between uric acid determined in blood and saliva. Statistical analysis did not reveal any other change in the salivary oxidative stress biomarkers. In conclusion, an acute session of resistance exercise induces oxidative stress in plasma of trained men after acute resistance training, which was not found in saliva samples except for uric acid.

Modulation of anxiety-like behaviour by Transient Receptor Potential Vanilloid Type 1 (TRPV1) channels located in the dorsolateral periaqueductal gray

The endocannabinoid anandamide is a possible agonist at the Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel, in addition to its agonist activity at cannabinoid type 1 (CB1) receptor. In the midbrain dorsolateral periaqueductal gray (dlPAC) our previous data showed that CB1 activation induces anxiolytic-like effects. However, the rote of TRPV1 has remained unclear. Thus, in the present study we tested the hypothesis that this channel would contribute to the modulation of anxiety-like behaviour in the dlPAG. Mate Wistar rats received local injections of the TRPV1 antagonist capsazepine (10-60 nmol) and were submitted to the elevated plus-maze (EPM) and to the Vogel test. In addition, animals received local injections of capsaicin (0.01-1nmol), a TRPV1 agonist, and were tested in the same models. In accordance with our hypothesis, capsazepine produced anxiolytic-like effects both in the EPM and in the Vogel test. Capsaicin mimicked these results, which might be attributed to its ability to quickly desensitize the channel. Altogether, our data suggest that, while CB1 receptors seem to inhibit aversive responses in the dlPAG, TRPV1 could facilitate them. Thus, CB1 and TRPV1 may have opposite functions in modulating anxiety-like behaviour in this region. (C) 2008 Elsevier B.V. and ECNP. All rights reserved.

Cellular prion protein modulates defensive attention and innate fear-induced behaviour evoked in transgenic mice submitted to an agonistic encounter with the tropical coral snake Oxyrhopus guibei

The cellular prion protein (PrPC) is a neuronal anchored glycoprotein that has been associated with distinct functions in the CNS, such as cellular adhesion and differentiation, synaptic plasticity and cognition. Here we investigated the putative involvement of the PrPC in the innate fear-induced behavioural reactions in wild-type (WT), PrPC knockout (Prnp(0/0)) and the PrPC overexpressing Tg-20 mice evoked in a prey versus predator paradigm. The behavioural performance of these mouse strains in olfactory discrimination tasks was also investigated. When confronted with coral snakes, mice from both Prnp(0/0) and Tg-20 strains presented a significant decrease in frequency and duration of defensive attention and risk assessment, compared to WT mice. Tg-20 mice presented decreased frequency of escape responses, increased exploratory behaviour, and enhancement of interaction with the snake, suggesting a robust fearlessness caused by PrPC overexpression. Interestingly, there was also a discrete decrease in the attentional defensive response (decreased frequency of defensive alertness) in Prnp(0/0) mice in the presence of coral snakes. Moreover, Tg-20 mice presented an increased exploration of novel environment and odors. The present findings indicate that the PrPC overexpression causes hyperactivity, fearlessness, and increased preference for visual, tactile and olfactory stimuli-associated novelty, and that the PrPC deficiency might lead to attention deficits. These results suggest that PrPC exerts an important role in the modulation of innate fear and novelty-induced exploration. (C) 2008 Published by Elsevier B.V.

Enhanced concentrations of relevant markers of nitric oxide formation after exercise training in patients with metabolic syndrome

Metabolic syndrome (MetS) denotes a clustering of risk factors that may affect nitric oxide (NO) bioavailability and predispose to cardiovascular diseases, which are delayed by exercise training. However, no previous study has examined how MetS affects markers of NO formation, and whether exercise training increases NO formation in MetS patients. Here, we tested these two hypotheses. We studied 48 sedentary individuals: 20 healthy controls and 28 MetS patients. Eighteen MetS patients were subjected to a 3-month exercise training (E+group), while the remaining 10 MetS patients remained sedentary (E-group). The plasma concentrations of nitrite, cGMP, and ADMA (asymmetrical dimethylarginine: an endogenous nitric oxide synthase inhibitor), and the whole blood nitrite concentrations were determined at baseline and after exercise training using an ozone-based chemiluminescence assay, and commercial enzyme immunoassays. Thiobarbituric acid reactive species (TBA-RS) were measured in the plasma to assess oxidative stress using a fluorometric method. We found that, compared with healthy subjects, patients with MetS have lower concentrations of markers of NO formation, including whole blood nitrite, plasma nitrite, and plasma cGMP, and increased oxidative stress (all P < 0.05). Exercise training increased the concentrations of whole blood nitrite and cGMP, and decreased both oxidative stress and the circulating concentrations of ADMA (both P < 0.05). These findings show clinical evidence for lower endogenous NO formation in patients with MetS, and for improvements in NO formation associated with exercise training in MetS patients. (C) 2008 Elsevier Inc. All rights reserved.

alpha(1)-Adrenoceptors in the lateral septal area modulate food intake behaviour in rats

Background and purpose: Control of food intake is a complex behaviour which involves many interconnected brain structures. The present work assessed if the noradrenergic system in the lateral septum (LS) was involved in the feeding behaviour of rats. Experimental approach: In the first protocol, the food intake of rats was measured. Then non-food-deprived animals received either 100 nL of 21 nmol of noradrenaline or vehicle unilaterally in the LS 10 min after local 10 nmol of WB4101, an alpha(1)-adrenoceptor antagonist, or vehicle. In the second protocol, different doses of WB4101 (1, 10 or 20 nmol in 100 nL) were microinjected bilaterally into the LS of rats, deprived of food for 18 h and food intake was compared to that of satiated animals. Key results: One-sided microinjection of noradrenaline into the LS of normal-fed rats evoked food intake, compared with vehicle-injected control animals, which was significantly reduced by alpha(1)-adrenoceptor antagonism. In a further investigation, food intake was significantly higher in food-deprived animals, compared to satiated controls. Pretreatment of the LS with WB4101 reduced food intake in only food-deprived animals in a dose-related manner, suggesting that the LS noradrenergic system was involved in the control of food intake. Conclusion and implications: Activation by local microinjection of noradrenaline of alpha(1)-adrenoceptors in the LS evoked food intake behaviour in rats. In addition, blockade of the LS alpha(1)-adrenoceptors inhibited food intake in food-deprived animals, suggesting that the LS noradrenergic system modulated food intake behaviour and satiation.

Role of IL-18 in overt pain-like behaviour in mice

There are evidences that targeting IL-18 might be beneficial to inhibit inflammatory symptoms, including hypernociception (decrease in nociceptive threshold). The mechanism of IL-18 mechanical hypernociception depends on endothelin in rats and mice. However, the role of IL-18 in overt pain-like behaviour remains undetermined. Therefore, we addressed the role of IL-18 in writhing response induced by intraperitoneal (i.p.) injection of phenyl-p-benzoquinone (PBQ) and acetic acid in mice. Firstly, it was detected that PBQ and acetic acid i.p. injection induced a dose-dependent number of writhes in Balb/c mice. Subsequently, it was observed that the PBQ- but not the acetic acid-induced writhes were diminished in IL-18 deficient ((-/-)) mice. Therefore, considering that IFN-gamma, endothelin and prostanoids mediate IL-18-induced mechanical hypernociception, we also investigated the role of these mediators in the same model of writhing response in which IL-18 participates. It was noticed that PBQ-induced writhes were diminished in IFN-gamma(-/-) mice and by the treatment with bosentan (mixed enclothelin ETA/ETB receptor antagonist), BQ 123 (cyclo[DTrp-DAsp-Pro-DVal-Leu], selective enclothelin ETA receptor antagonist), BQ 788 (N-cys-2,6-dimethylpiperidinocarbonyl-L-methylleucyl-D-1 -methoxycarboyl-D-norleucine, selective endothelin ETB receptor antagonist) or indomethacin (cycloxigenase inhibitor). Thus, IL-18, IFN-gamma, endothelin acting on endothelin ETA and ETB receptors, and prostanoids mediate PBQ-induced writhing response in mice. To conclude, these results further advance the understanding of the physiopathology of overt pain-like behaviour, and suggest for the first time a role for IL-18 in writhing response in mice. (C) 2008 Elsevier B.V. All rights reserved.

BED NUCLEUS OF THE STRIA TERMINALIS alpha(1)- AND alpha(2)-ADRENOCEPTORS DIFFERENTIALLY MODULATE THE CARDIOVASCULAR RESPONSES TO EXERCISE IN RATS

Dynamic exercise evokes sustained blood pressure and heart rate (HR) increases. Although it is well accepted that there is a CNS mediation of cardiovascular adjustments during dynamic exercise, information on the role of specific CNS structures is still limited. The bed nucleus of the stria terminalis (BST) is involved in exercise-evoked cardiovascular responses in rats. However, the specific neurotransmitter involved in BST-related modulation of cardiovascular responses to dynamic exercise is still unclear. In the present study, we investigated the role of local BST adrenoceptors in the cardiovascular responses evoked when rats are submitted to an acute bout of exercise on a rodent treadmill. We observed that bilateral microinjection of the selective alpha 1-adrenoceptor antagonist WB4101 into the BST enhanced the HR increase evoked by dynamic exercise without affecting the mean arterial pressure (MAP) increase. Bilateral microinjection of the selective alpha 2-adrenoceptor antagonist RX821002 reduced exercise-evoked pressor response without changing the tachycardiac response. BST pretreatment with the nonselective beta-adrenoceptor antagonist propranolol did not affect exercise-related cardiovascular responses. BST treatment with either WB4101 or RX821002 did not affect motor performance in the open-field test, which indicates that effects of BST adrenoceptor antagonism in exercise-evoked cardiovascular responses were not due to changes in motor activity. The present findings are the first evidence showing the involvement of CNS adrenoceptors in cardiovascular responses during dynamic exercise. Our results indicate an inhibitory influence of BST alpha 1-adrenoceptor on the exercise-evoked HR response. Data also point to a facilitatory role played by the activation of BST alpha 2-adrenoceptor on the pressor response to dynamic exercise. (C) 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Nitric oxide inhibition in paraventricular nucleus on cardiovascular and autonomic modulation after exercise training in unanesthetized rats

It is well known that regular physical exercise alter cardiac function and autonomic modulation of heart rate variability (HRV). The paraventricular nucleus of hypothalamus (PVN) is an important site of integration for autonomic and cardiovascular responses, where nitric oxide (NO) plays an important role. The aim of our study was to evaluate the cardiovascular parameters and autonomic modulation by means of spectral analysis after nitric oxide synthase (NOS) inhibition in the PVN in conscious sedentary (S) or swimming trained (ST) rats. After swimming training protocol, adult male Wistar rats, instrumented with guide cannulas to PVN and femoral artery and vein catheters were submitted to mean arterial pressure (MAP) and heart rate (HR) recording. At baseline, the physical training induced a resting bradycardia (S: 374 +/- 5, ST: 346 +/- 1 bpm) and promoted adaptations in HRV characterized by an increase in high-frequency oscillations (HF; 26.43 +/- 6.91 to 88.96 +/- 244) and a decrease in low-frequency oscillations (LF; 73.57 +/- 6.91 to 11.04 +/- 2.44) in normalized units. The microinjection of N(omega)-nitro-L-arginine methyl ester (L-NAME) in the PVN of sedentary and trained rats promoted increase in MAP and HR. L-NAME in the PVN did not significantly alter the spectral parameters of HRV of sedentary animals, however in the trained rats increased LF oscillations (11.04 +/- 2.44 to 27.62 +/- 6.97) and decreased HF oscillations (88.96 +/- 2.44 to 72.38 +/- 6.97) in normalized units compared with baseline. Our results suggest that NO in the PVN may collaborate to cardiac autonomic modulation after exercise training. (c) 2010 Elsevier B.V. All rights reserved.

Cannabidiol inhibitory effect on marble-burying behaviour: involvement of CB1 receptors

Cannabidiol (CBD) is a major nonpsychotomimetic component of Cannabis sativa that has been shown to have an anxiolytic effect in human and animal models. Earlier studies suggest that these effects involve facilitation of serotonin, a neurotransmitter that has also been related to obsessive-compulsive disorder. On the basis of this evidence, this study investigated the effects of CBD in C57BL/6J mice submitted to the marble-burying test (MBT), an animal model proposed to reflect compulsive behaviour. CBD (15, 30 and 60 mg/kg) induced a significant decrease in the number of buried marbles compared with controls (34, 41 and 48%, respectively). A similar, although larger, decrease was also found after the serotonin selective reuptake inhibitor paroxetine (10 mg/kg, 77% decrease) and the benzodiazepine diazepam (2.5 mg/kg, 84% decrease). The effect of CBD (30 mg/kg) was still significant after 7 days of daily repeated administration, whereas the effect of diazepam disappeared. Pretreatment with WAY100635 (3 mg/kg), a 5HT1A receptor antagonist, prevented the effects of paroxetine but failed to alter those of CBD. These latter effects, however, were prevented by pretreatment with the CB1 receptor antagonist AM251 (1 mg/kg). These results indicated that CBD and paroxetine decrease the number of buried marbles in the MBT through distinct pharmacological mechanisms. They also suggest a potential role of drugs acting on the cannabinoid system in modulating compulsive behaviour. Behavioural Pharmacology 21: 353-358 (C) 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.

The bed nucleus of the stria terminalis modulates exercise-evoked cardiovascular responses in rats

Dynamic exercise evokes sustained cardiovascular changes, which are characterized by blood pressure and heart rate (HR) increases. Although it is well accepted that there is a central nervous system (CNS) mediation of cardiovascular adjustments during dynamic exercise, information on the role of specific CNS structures is limited. The bed nucleus of the stria terminalis (BST) is a forebrain structure known to be involved in central cardiovascular control. Based on this, we tested the hypothesis that BST modulates HR and mean arterial pressure (MAP) responses evoked when rats are submitted to dynamic exercise. Male Wistar rats were tested at three levels of exercise (0.4, 0.8 and 1 km h-1) on a rodent treadmill before and after BST treatment with CoCl(2), a non-selective neurotransmission blocker. Bilateral microinjection of CoCl(2) (1 nmol in 100 nl artificial cerebrospinal fluid) into the BST reduced the pressor response to exercise at 0.4 km h-1 as well as the tachycardic responses evoked by exercise at 0.4, 0.8 and 1 km h-1. The BST treatment with CoCl(2) did not affect baseline MAP or HR, suggesting a lack of tonic BST influence on cardiovascular parameters at rest. Moreover, BST treatment with CoCl(2) did not affect motor performance in the open-field test, which indicates that effects of BST inhibition on cardiovascular responses to dynamic exercise are not due to changes in motor activity. The present results suggest that local neurotransmission in the BST modulates exercise-related cardiovascular adjustments. Data indicate that BST facilitates pressor and tachycardic responses evoked by dynamic exercise in rats.

GABA(A) receptor blockade in dorsomedial and ventromedial nuclei of the hypothalamus evokes panic-like elaborated defensive behaviour followed by innate fear-induced antinociception

Dysfunction in the hypothalamic GABAergic system has been implicated in panic syndrome in humans. Furthermore, several studies have implicated the hypothalamus in the elaboration of pain modulation. Panic-prone states are able to be experimentally induced in laboratory animals to study this phenomenon. The aim of the present work was to investigate the involvement of medial hypothalamic nuclei in the organization of panic-like behaviour and the innate fear-induced oscillations of nociceptive thresholds. The blockade of GABA(A) receptors in the neuronal substrates of the ventromedial. or dorsomedial hypothalamus was followed by elaborated defensive panic-like reactions. Moreover, innate fear-induced antinociception was consistently elicited after the escape behaviour. The escape responses organized by the dorsomedial and ventromedial hypothalamic nuclei were characteristically more elaborated, and a remarkable exploratory behaviour was recorded during GABA(A) receptor blockade in the medial hypothalamus. The motor characteristic of the elaborated defensive escape behaviour and the patterns of defensive alertness and defensive immobility induced by microinjection of the bicuculline either into the dorsomedial. or into the ventromedial hypothalamus were very similar. This was followed by the same pattern of innate fear-induced antinociceptive response that lasted approximately 40 min after the elaborated defensive escape reaction in both cases. These findings suggest that dysfunction of the GABA-mediated neuronal system in the medial hypothalamus causes panic-like responses in laboratory animals, and that the elaborated escape behaviour organized in both dorsomedial and ventromedial hypothalamic nuclei are followed by significant innate-fear-induced antinociception. Our findings indicate that the GABA(A) receptor of dorsomedial and ventromedial hypothalamic nuclei are critically involved in the modulation of panic-like behaviour. (C) 2009 Elsevier B.V. All rights reserved.