Missale, Cristina, S. Russel Nash, Susan W. Robinson, Mohamed Jaber, and Marc G. Caron. Dopamine Receptors: From Structure to Function. Physiol. Rev. 78: 189–225, 1998. — The diverse physiological actions of dopamine are mediated by at least five distinct G protein-coupled receptor subtypes. Two D1-like receptor subtypes (D1 and D5) couple to the G protein Gs and activate adenylyl cyclase. The other receptor subtypes belong to the D2-like subfamily (D2 , D3 , and D4) and are prototypic of G protein-coupled receptors that inhibit adenylyl cyclase and activate K+ channels. The genes for the D1 and D5 receptors are intronless, but pseudogenes of the D5 exist. The D2 and D3 receptors vary in certain tissues and species as a result of alternative splicing, and the human D4 receptor gene exhibits extensive polymorphic variation. In the central nervous system, dopamine receptors are widely expressed because they are involved in the control of locomotion, cognition, emotion, and affect as well as neuroendocrine s...

Dopamine Receptors: From Structure to Function

Background: Pulmonary rehabilitation is recognized as a core component of the management of individuals with chronic respiratory disease. Since the 2006 American Thoracic Society (ATS)/European Respiratory Society (ERS) Statement on Pulmonary Rehabilitation, there has been considerable growth in our knowledge of its efficacy and scope.

Purpose: The purpose of this Statement is to update the 2006 document, including a new definition of pulmonary rehabilitation and highlighting key concepts and major advances in the field.

Methods: A multidisciplinary committee of experts representing the ATS Pulmonary Rehabilitation Assembly and the ERS Scientific Group 01.02, “Rehabilitation and Chronic Care,” determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant clinical and scientific expertise. The final content of this Statement was agreed on by all members.

Results: An updated definition of pulmonary rehabilitation is proposed. New data are presented on the science and application of pulmonary rehabilitation, including its effectiveness in acutely ill individuals with chronic obstructive pulmonary disease, and in individuals with other chronic respiratory diseases. The important role of pulmonary rehabilitation in chronic disease management is highlighted. In addition, the role of health behavior change in optimizing and maintaining benefits is discussed.

Conclusions: The considerable growth in the science and application of pulmonary rehabilitation since 2006 adds further support for its efficacy in a wide range of individuals with chronic respiratory disease

Read More: http://www.atsjournals.org/doi/abs/10.1164/rccm.201309-1634ST

/pdf/an-official-american-thoracic-society-european-respiratory-5fbz6s326i.pdf

An official American thoracic society/European respiratory society statement: Key concepts and advances in pulmonary rehabilitation

This review aims to summarize the latest developments with regard to physical fitness and several health outcomes in young people. The literature reviewed suggests that (1) cardiorespiratory fitness levels are associated with total and abdominal adiposity; (2) both cardiorespiratory and muscular fitness are shown to be associated with established and emerging cardiovascular disease risk factors; (3) improvements in muscular fitness and speed/agility, rather than cardiorespiratory fitness, seem to have a positive effect on skeletal health; (4) both cardiorespiratory and muscular fitness enhancements are recommended in pediatric cancer patients/survivors in order to attenuate fatigue and improve their quality of life; and (5) improvements in cardiorespiratory fitness have positive effects on depression, anxiety, mood status and self-esteem, and seem also to be associated with a higher academic performance. In conclusion, health promotion policies and physical activity programs should be designed to improve cardiorespiratory fitness, but also two other physical fitness components such us muscular fitness and speed/agility. Schools may play an important role by identifying children with low physical fitness and by promoting positive health behaviors such as encouraging children to be active, with special emphasis on the intensity of the activity.

Physical fitness in childhood and adolescence: a powerful marker of health

Regulation of noradrenaline release by presynaptic receptor systems.

Renin-angiotensin system: biochemistry and mechanisms of action.

Objective: To investigate the relationships between the time spent in specific intensities of activity and inactivity, cardiorespiratory fitness and body composition in children. Methods: A cross-sectional study was conducted in a random sample of schools. Height, weight and waist circumference were measured in 224 children aged 7–10 years. Cardiorespiratory fitness was estimated by the 20 m multistage running test, and physical activity was measured over 4 days by the RT3 (a triaxial accelerometer). Time each day spent in moderate and vigorous intensities of activity was calculated. Results: Twelve schools agreed to participate in the study. Body composition and fitness data were obtained for 224 children and activity data for 152 children. Boys were found to take part in about twice as much vigorous and hard activity as girls (mean (95% confidence interval) 64.3 (53.2 to 75.4) min in boys compared with 37 (33.1 to 40.9) min in girls; p r  = –0.31, p r  = 0.33, p r  = –0.274, p r  = –0.503, p r  = –0.286, p Conclusion: In boys, body composition was inversely related to fitness and to vigorous activity and was positively related to inactivity. In girls, body composition was related to fitness but not to specific components of physical activity.

https://bjsm.bmj.com/content/bjsports/41/5/311.full.pdf

Relationship between the intensity of physical activity, inactivity, cardiorespiratory fitness and body composition in 7–10-year-old Dublin children

During physical activity, there is a graded withdrawal of vagal cardiac tone and a graded increase in sympathetic cardiac and vasomotor tone, initiated through both central command from the somatic motor cortex and muscle chemoreceptive and mechanoreceptive inputs. In parallel, there is an upward resetting of the operating point of the arterial baroreflex, with preserved reflex sensitivity. In contrast to the traditional interpretation that blood flow through exercising muscle is independent of vasomotor neural influences because of the dominance of local dilator metabolites, recent evidence suggests that both constrictor and dilator sympathetic neural influences may be involved in determining absolute levels of perfusion. Post-exercise, there is a period of relative hypotension that is associated with decreased peripheral resistance. Some, but not all, evidence indicates a causal role for reduced sympathetic drive. Chronic exercise training appears to reduce resting sympathetic activity, with parallel changes in the gain of a variety of cardiovascular autonomic reflexes initiated from cardiovascular sites. These changes may be attributable at least partly to masking of arterial baroreflexes by the impact of elevated blood volume on low-pressure baroreceptors. The reductions in sympathetic drive that follow training are more pronounced in patients with essential hypertension than in normotensive individuals and are likely to underlie the anti-hypertensive effect of exercise.

The effects of exercise and training on human cardiovascular reflex control

Extending a home from hospital care programme for COPD exacerbations to include pulmonary rehabilitation

The innervation of the extrinsic uterine arterial supply of the guinea pig has been studied using an isolated perfused preparation. The preparation was normally at minimal tone and responded to periarterial stimulation by a vaso-constriction which was mimicked by norepinephrine and abolished by bretylium. Constrictor responses both to stimulation and to norepinephrine were similar in both pregnant and non-pregnant states. In pregnant preparations, raising the tone of the vessels with norepinephrine revealed a powerful dilator response to periarterial stimulation. This response was mimicked by acetylcholine, potentiated by anticholinesterases, reduced by hyoscine, and abolished by-local anesthetic treatment. In contrast, virgin preparations showed only a weak dilator response to stimulation, while the response to acetylcholine even at high concentrations was usually negligible. Histochemical examination of the vessels revealed a dense plexus of fine nerve fibers exhibiting high acetylcholinesterase activity along the main uterine artery. The fibers lay in close apposition to the vascular muscle layer. Nerve fibers exhibited fluorescence for catecholamines were also abundant, but were distributed along the secondary as well as the main arteries. It is concluded that the uterine arterial supply of the guinea pig is innervated by both adrenergic constrictor and cholinergic dilator fibers. The dilator fibers appear to be functional only during pregnancy. The possibility of a noncholinergic dilator innervation is also discussed.

Dual Vasoconstrictor and Vasodilator Innervation of the Uterine Arterial Supply in the Guinea Pig

— The dopamine (DA) content of the canine renal cortex is greater than can be attributed to its presence in noradrenergic axons only. Most of the excess DA is in the outer part of the cortex. By fluorescence histochemistry numerous catecholamine-containing axons are seen to be associated with renal cortical arteries and arterioles. The fluorescence is abolished following treatment of animals with 6-hydroxydopamine or with reserpine, but is restored to some axons if reserpine is followed by systemic administration of 1-DOPA. This procedure does not restore fluorescence to atrial noradrenergic axons after reserpine-induced depletion. Pretreatment of animals with guanethidine abolishes axonal fluorescence and depletes tissue NA and DA from atrium, but in renal cortex the tissue DA level is little affected and some fluorescent axons remain. These results are discussed in the light of previous functional evidence for dopaminergic autonomic axons in the canine kidney.

Christopher Bell

Papers

Relationship between the intensity of physical activity, inactivity, cardiorespiratory fitness and body composition in 7–10-year-old Dublin children

The effects of exercise and training on human cardiovascular reflex control

Extending a home from hospital care programme for COPD exacerbations to include pulmonary rehabilitation

Dual Vasoconstrictor and Vasodilator Innervation of the Uterine Arterial Supply in the Guinea Pig

Dopamine-containing vasomotor nerves in the dog kidney