Testosterone Supplementation Induces Age-Dependent Augmentation of the Hypoxic Ventilatory Response in Male Rats With Contributions From the Carotid Bodies

Excessive carotid body responsiveness to O2 and/or CO2/H+ stimuli contributes to respiratory instability and apneas during sleep. In hypogonadal men, testosterone supplementation may increase the risk of sleep-disordered breathing; however, the site of action is unknown. The present study tested the hypothesis that testosterone supplementation potentiates carotid body responsiveness to hypoxia in adult male rats. Because testosterone levels decline with age, we also determined whether these effects were age-dependent. In situ hybridization determined that androgen receptor mRNA was present in the carotid bodies and caudal nucleus of the solitary tract of adult (69 days old) and aging (193–206 days old) male rats. In urethane-anesthetized rats injected with testosterone propionate (2 mg/kg; i.p.), peak breathing frequency measured during hypoxia (FiO2 = 0.12) was 11% greater vs. the vehicle treatment group. Interestingly, response intensity following testosterone treatment was positively correlated with animal age. Exposing ex vivo carotid body preparations from young and aging rats to testosterone (5 nM, free testosterone) 90–120 min prior to testing showed that the carotid sinus nerve firing rate during hypoxia (5% CO2 + 95% N2; 15 min) was augmented in both age groups as compared to vehicle (<0.001% DMSO). Ventilatory measurements performed using whole body plethysmography revealed that testosterone supplementation (2 mg/kg; i.p.) 2 h prior reduced apnea frequency during sleep. We conclude that in healthy rats, age-dependent potentiation of the carotid body’s response to hypoxia by acute testosterone supplementation does not favor the occurrence of apneas but rather appears to stabilize breathing during sleep.

Validación al castellano de la Body Responsiveness Connection Scale (Escala de Respuesta Corporal (ERC) en médicos internos del hospital San Rafael de Tunja in Colombia

La conexión entre mente y cuerpo hace referencia al proceso de terapias de autorregulación diseñadas para aumentar tanto el bienestar físico como el mental. Objetivo: Determinar las propiedades psicométricas de la Escala de Respuesta Corporal (ERC) en una población de médicos internos y residentes del hospital San Rafael, en la ciudad de Tunja (Colombia). Material y métodos: Se realizó una traducción y retro-traducción de la Body Responseveness Connection Scale. El instrumento fue aplicado a 112 médicos internos del Hospital San Rafael de Tunja, entre18 y 35 años. Se analizó la consistencia interna del instrumento mediante el test α Cronbach, y la fiabilidad test- retest con el coeficiente de correlación intraclase. Resultados: La edad promedio de los participantes fue de 23,5 años (DE ± 2,06 años), la mayoría fueron mujeres. El 38.4% provenían de universidades públicas y el 62,4% no realizaban actividades adicionales en su tiempo libre. La consistencia interna de la escala fue de 0,87. El coeficiente de correlación fue mayor de 0,6 en la mayoría de los ítems. Conclusiones: La Escala de Respuesta Corporal en personal de la salud presenta propiedades psicométricas similares a la versión original, con adecuada confiabilidad y validez, factores que permiten evaluar aspectos relevantes de conciencia y disociación corporal

Yoga for People With Chronic Pain in a Community-Based Setting: A Feasibility and Pilot RCT

The purpose of this feasibility pilot study was to assess benefits of 8 weeks of yoga in people with chronic pain. Participants completed baseline assessments and were randomized to yoga or usual care. Yoga was offered twice a week for 8 weeks. We assessed feasibility and the Brief Pain Inventory (BPI) was the primary outcome, assessing pain-severity and pain interference on daily activities. Eighty-three people were recruited; 67 people completed the study and were included in the analyses. Average age of participants was 50.78 ± 10.43 years and most participants had pain >10 years. The intervention appeared feasible and there were significant improvements ( P < .05) in multiple measures for the yoga group, including a decrease in BPI interference scores from 7.15 ± 1.70 to 6.14 ± 2.21 ( P = .007). There was a significant difference in body responsiveness and pain management scores between groups at 8 weeks. It appears that yoga was feasible and positively influenced multiple outcome measures for people with chronic pain.

Interindividual variability in the dose-specific effect of dopamine on carotid chemoreceptor sensitivity to hypoxia

Human studies use varying levels of low-dose (1-4 μg·kg−1·min−1) dopamine to examine peripheral chemosensitivity, based on its known ability to blunt carotid body responsiveness to hypoxia. However, the effect of dopamine on the ventilatory responses to hypoxia is highly variable between individuals. Thus we sought to determine 1) the dose response relationship between dopamine and peripheral chemosensitivity as assessed by the ventilatory response to hypoxia in a cohort of healthy adults, and 2) potential confounding cardiovascular responses at variable low doses of dopamine. Young, healthy adults ( n = 30, age = 32 ± 1, 24 male/6 female) were given intravenous (iv) saline and a range of iv dopamine doses (1–4 μg·kg−1·min−1) prior to and throughout five hypoxic ventilatory response (HVR) tests. Subjects initially received iv saline, and after each HVR the dopamine infusion rate was increased by 1 μg·kg−1·min−1. Tidal volume, respiratory rate, heart rate, blood pressure, and oxygen saturation were continuously measured. Dopamine significantly reduced HVR at all doses ( P < 0.05). When subjects were divided into high ( n = 13) and low ( n = 17) baseline chemosensitivity, dopamine infusion (when assessed by dose) reduced HVR in the high group only ( P < 0.01), with no effect of dopamine on HVR in the low group ( P > 0.05). Dopamine infusion also resulted in a reduction in blood pressure (3 μg·kg−1·min−1) and total peripheral resistance (1–4 μg·kg−1·min−1), driven primarily by subjects with low baseline chemosensitivity. In conclusion, we did not find a single dose of dopamine that elicited a nadir HVR in all subjects. Additionally, potential confounding cardiovascular responses occur with dopamine infusion, which may limit its usage.