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Analysis of cardiovascular responses during Valsalva maneuver and maximal expiratory pressure in healthy men
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Abstracts / Autonomic Neuroscience: Basic and Clinical 177 (2013) 297–319
O. Takahashi (Clinical Physiology Unit, Sakura Medical Center, Toho University, Sakura, Japan) Aims of study: The incidence of overactive bladder (OAB) in general population over 40 years in age is 12.4–16.6%, which increases with age (35–50%). Mechanism of OAB is age related changes in the bladder itself, or central nervous system changes innervating the bladder. Studies have shown urothelial/suburothelial changes and increased bladder afferents, while in the brain the frontal micturition area is deactivated that normally suppresses the bladder. Question arises whether anticholinergic medication could reverse the latter. To clarify this, we performed a real-time NIRS (near-infrared spectroscopy)-urodynamic study in OAB patients before and after administration of an anticholinergic agent tolterodine. Methods: We have 13 OAB patients; 9 male, 4 female; mean age 73 years [46–84]. Before and after administration of 3 months, 4 mg/day tolterodine, all patients underwent a NIRS-urodynamics. Cerebral changes in the oxy-hemoglobin concentration (oxy-Hb) were sampled by optical topograph systems for NIRS (OMM-3000, Shimadzu Inc, Kyoto, Japan). Concentration changes in oxy-Hb were calculated based on a modified Beer–Lambert approach. According to the Talairach's brain atlas, the probe array covers the areas 8, 10, 44, 46 and the more anterior parts of the frontal cortex. Results: Tolterodine ameliorated night-time frequency (by OABsymptom scale, p b 0.05) and increased first sensation volume (290 ml to 359 ml, p b 0.01) significantly, while it did not increase post-void residual volume. The number of patients with detrusor overactivity did not lessen significantly (11 to 9). A real-time NIRS-urodynamic study showed that tolterodine significantly activated the frontal micturition area (p b 0.05). It was prominent in Brodmann's area 8,10 of the prefrontal cortex. Conclusion: A real-time NIRS-urodynamic study showed that tolterodine, an anticholinergic agent, activates the frontal micturition area of OAB patients that was prominent in the Brodmann's area 8,10 of the prefrontal cortex. Therefore, it is suggested that tolterodine reverses frontal deactivation in OAB patients. doi:10.1016/j.autneu.2013.08.004
Abstract 3.5 Analysis of cardiovascular responses during Valsalva maneuver and maximal expiratory pressure in healthy men V. Minatel, A.C.M. Takahashi, N.M. Perseguini, J.C. Milan, V. CastelloSimões, E.C. Gomes, A. Borghi-Silva, A.M. Catai (Universidade Federal de São Carlos, Brazil) Background/aim: The assessment of respiratory muscle strength (RMS), measured by the maximal expiratory pressure (MEP), has been applied to identify the aging effects on RMS. However, this measure is not indicated in some clinical situations, because it is believed that the cardiovascular responses obtained in MEP are similar to those observed in Valsalva maneuver (VM). So, the main purpose of this study is to compare the responses of mean arterial pressure (PAM), cardiac output (CO), stroke volume (SV), heart rate (HR) and peripheral vascular resistance (PVR) during VM and MEP. Additionally, this study aims to evaluate the aging effect on the cardiovascular responses during the VM and MEP in the groups studied. Methods: Twenty-eight healthy male volunteers participated in this study, who were divided in two groups: younger (YG-n = 15, 25 ± 5years) and middle aged (MAG-n = 13, 50 ± 5years). All volunteers were evaluated, instructed and allowed to familiarize with VM
and MEP, which were performed at sitting position. The VM was characterized by an expiratory effort (40 mm Hg) against a manometer for 15 s, and the MEP measure has been performed according to the American Thoracic Society. For analysis, the following were used: the cardiovascular variation (ΔPAM, ΔCO, ΔSV, ΔHR and ΔPVR); and the cardiovascular variation during isotime (3s) (ΔPAMisotime, ΔCOisotime, ΔSVisotime, ΔHRisotime and ΔPVRisotime). For statistical analysis, we used two-way ANOVA (p b 0.05). Results: a) No difference between the ΔCO was observed during the maneuvers (p N 0.05); b) the ΔPAM, ΔPAMisotime and ΔPVRisotime obtained during MEP were higher than in VM (p b 0.05), but, the ΔHR, ΔHRisotime and ΔSV were higher in VM (p b 0.05); c) the MAG had higher values of ΔPVR, ΔPVRisotime and lower ΔHRisotime than the YG (p b 0.05). Conclusion: The MEP generates cardiovascular responses similar to those observed during VM, related to the CO, and higher values of PAM and PVR, by different physiological mechanisms. Furthermore, it seems like aging influences the HR and PVR responses during VM and MEP. Financial support: FAPESP (10/52070-4); CNPq, CAPES. doi:10.1016/j.autneu.2013.08.005
Abstract 3.6 Transgenic rats with ataxin3-mediated destruction of orexin neurons have a diminished brown adipose tissue (BAT) thermogenic response to confrontation with an intruder rat W. Blessing, M. Mohammed, Y. Ootsuka (Human Physiology, Flinders University, Adelaide, Australia), M. Yanagisawa (Department of Molecular Genetics, University of Texas Southwestern Medical Centre, Dallas, United States) Brown adipose tissue (BAT) thermogenesis is activated when rats explore the environment (1–2). We now examine BAT thermogenic responses to salient stimuli (introduction of an intruder rat) in transgenic rats with ataxin3-mediated destruction of orexin neurons, compared with wild type controls (3). Under inhaled isoflurane (2% in oxygen) anaesthesia, transgenic or wild type rats (300–450 g) were instrumented with chronically implanted thermistors to measure BAT and body temperature (Blessing et al., 2012). All surgical procedures were performed in accord with the Animal Welfare Ethics Committee of Flinders University. Thermistor cables were passed subcutaneously and connected to a headpiece fixed to the skull with dental cement. After oneweek recovery the unrestrained rats were housed singly in a quiet closed temperature controlled (24–26 °C) cage and BAT and body temperatures were continuously (1 Hz sampling rate) recorded via a flexible cable and a swivel. A normal Sprague–Dawley rat was introduced to the cage, and removed after 30 min. Pre-intruder BAT and body temperatures were compared with average temperatures 24–29 min after the introduction of the intruder. Intruder-induced increases in BAT and body temperatures were less in transgenic rats (0.30 ± 0.21°K and 0.34 ± 0.21°K respectively) than the corresponding increases in wild type rats (1.34 ± 0.35°K and 0.94 ± 0.14°K, n = 6 transgenic and 6 wild type rats, P b 0.05 for both temperatures). Our results suggest that the function of hypothalamic orexin neurons contributes to the amplitude of BAT thermogenesis that occurs when rats are confronted with salient stimuli. 1. Ootsuka et al. Neurosci. 2009. 2. Blessing et al. Physiol Behav. 2012. 3. Beuckmann et al. J. Neurosci. 2004. doi:10.1016/j.autneu.2013.08.006
Abstracts / Autonomic Neuroscience: Basic and Clinical 177 (2013) 297–319
O. Takahashi (Clinical Physiology Unit, Sakura Medical Center, Toho University, Sakura, Japan) Aims of study: The incidence of overactive bladder (OAB) in general population over 40 years in age is 12.4–16.6%, which increases with age (35–50%). Mechanism of OAB is age related changes in the bladder itself, or central nervous system changes innervating the bladder. Studies have shown urothelial/suburothelial changes and increased bladder afferents, while in the brain the frontal micturition area is deactivated that normally suppresses the bladder. Question arises whether anticholinergic medication could reverse the latter. To clarify this, we performed a real-time NIRS (near-infrared spectroscopy)-urodynamic study in OAB patients before and after administration of an anticholinergic agent tolterodine. Methods: We have 13 OAB patients; 9 male, 4 female; mean age 73 years [46–84]. Before and after administration of 3 months, 4 mg/day tolterodine, all patients underwent a NIRS-urodynamics. Cerebral changes in the oxy-hemoglobin concentration (oxy-Hb) were sampled by optical topograph systems for NIRS (OMM-3000, Shimadzu Inc, Kyoto, Japan). Concentration changes in oxy-Hb were calculated based on a modified Beer–Lambert approach. According to the Talairach's brain atlas, the probe array covers the areas 8, 10, 44, 46 and the more anterior parts of the frontal cortex. Results: Tolterodine ameliorated night-time frequency (by OABsymptom scale, p b 0.05) and increased first sensation volume (290 ml to 359 ml, p b 0.01) significantly, while it did not increase post-void residual volume. The number of patients with detrusor overactivity did not lessen significantly (11 to 9). A real-time NIRS-urodynamic study showed that tolterodine significantly activated the frontal micturition area (p b 0.05). It was prominent in Brodmann's area 8,10 of the prefrontal cortex. Conclusion: A real-time NIRS-urodynamic study showed that tolterodine, an anticholinergic agent, activates the frontal micturition area of OAB patients that was prominent in the Brodmann's area 8,10 of the prefrontal cortex. Therefore, it is suggested that tolterodine reverses frontal deactivation in OAB patients. doi:10.1016/j.autneu.2013.08.004
Abstract 3.5 Analysis of cardiovascular responses during Valsalva maneuver and maximal expiratory pressure in healthy men V. Minatel, A.C.M. Takahashi, N.M. Perseguini, J.C. Milan, V. CastelloSimões, E.C. Gomes, A. Borghi-Silva, A.M. Catai (Universidade Federal de São Carlos, Brazil) Background/aim: The assessment of respiratory muscle strength (RMS), measured by the maximal expiratory pressure (MEP), has been applied to identify the aging effects on RMS. However, this measure is not indicated in some clinical situations, because it is believed that the cardiovascular responses obtained in MEP are similar to those observed in Valsalva maneuver (VM). So, the main purpose of this study is to compare the responses of mean arterial pressure (PAM), cardiac output (CO), stroke volume (SV), heart rate (HR) and peripheral vascular resistance (PVR) during VM and MEP. Additionally, this study aims to evaluate the aging effect on the cardiovascular responses during the VM and MEP in the groups studied. Methods: Twenty-eight healthy male volunteers participated in this study, who were divided in two groups: younger (YG-n = 15, 25 ± 5years) and middle aged (MAG-n = 13, 50 ± 5years). All volunteers were evaluated, instructed and allowed to familiarize with VM
and MEP, which were performed at sitting position. The VM was characterized by an expiratory effort (40 mm Hg) against a manometer for 15 s, and the MEP measure has been performed according to the American Thoracic Society. For analysis, the following were used: the cardiovascular variation (ΔPAM, ΔCO, ΔSV, ΔHR and ΔPVR); and the cardiovascular variation during isotime (3s) (ΔPAMisotime, ΔCOisotime, ΔSVisotime, ΔHRisotime and ΔPVRisotime). For statistical analysis, we used two-way ANOVA (p b 0.05). Results: a) No difference between the ΔCO was observed during the maneuvers (p N 0.05); b) the ΔPAM, ΔPAMisotime and ΔPVRisotime obtained during MEP were higher than in VM (p b 0.05), but, the ΔHR, ΔHRisotime and ΔSV were higher in VM (p b 0.05); c) the MAG had higher values of ΔPVR, ΔPVRisotime and lower ΔHRisotime than the YG (p b 0.05). Conclusion: The MEP generates cardiovascular responses similar to those observed during VM, related to the CO, and higher values of PAM and PVR, by different physiological mechanisms. Furthermore, it seems like aging influences the HR and PVR responses during VM and MEP. Financial support: FAPESP (10/52070-4); CNPq, CAPES. doi:10.1016/j.autneu.2013.08.005
Abstract 3.6 Transgenic rats with ataxin3-mediated destruction of orexin neurons have a diminished brown adipose tissue (BAT) thermogenic response to confrontation with an intruder rat W. Blessing, M. Mohammed, Y. Ootsuka (Human Physiology, Flinders University, Adelaide, Australia), M. Yanagisawa (Department of Molecular Genetics, University of Texas Southwestern Medical Centre, Dallas, United States) Brown adipose tissue (BAT) thermogenesis is activated when rats explore the environment (1–2). We now examine BAT thermogenic responses to salient stimuli (introduction of an intruder rat) in transgenic rats with ataxin3-mediated destruction of orexin neurons, compared with wild type controls (3). Under inhaled isoflurane (2% in oxygen) anaesthesia, transgenic or wild type rats (300–450 g) were instrumented with chronically implanted thermistors to measure BAT and body temperature (Blessing et al., 2012). All surgical procedures were performed in accord with the Animal Welfare Ethics Committee of Flinders University. Thermistor cables were passed subcutaneously and connected to a headpiece fixed to the skull with dental cement. After oneweek recovery the unrestrained rats were housed singly in a quiet closed temperature controlled (24–26 °C) cage and BAT and body temperatures were continuously (1 Hz sampling rate) recorded via a flexible cable and a swivel. A normal Sprague–Dawley rat was introduced to the cage, and removed after 30 min. Pre-intruder BAT and body temperatures were compared with average temperatures 24–29 min after the introduction of the intruder. Intruder-induced increases in BAT and body temperatures were less in transgenic rats (0.30 ± 0.21°K and 0.34 ± 0.21°K respectively) than the corresponding increases in wild type rats (1.34 ± 0.35°K and 0.94 ± 0.14°K, n = 6 transgenic and 6 wild type rats, P b 0.05 for both temperatures). Our results suggest that the function of hypothalamic orexin neurons contributes to the amplitude of BAT thermogenesis that occurs when rats are confronted with salient stimuli. 1. Ootsuka et al. Neurosci. 2009. 2. Blessing et al. Physiol Behav. 2012. 3. Beuckmann et al. J. Neurosci. 2004. doi:10.1016/j.autneu.2013.08.006