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The American Journal of Physiology: Regulatory, Integrative & Comparative Physiology has issued a call for papers on the topic of cardiovascular regulation during exercise, specifically focusing on the role of biological sex and the consequences of aging. The editors are seeking original research, short reports, and reviews that explore areas such as autonomic control of circulation, skeletal muscle, cerebral and cardiac blood flow, cardiac regulation, hemodynamic regulation, and thermal challenges. The aim is to better understand the sex-specific differences in cardiovascular responses to exercise and how they change throughout the lifespan. The call also emphasizes the need to consider the effects of aging, age-related diseases, and medications commonly prescribed to older adults on cardiovascular regulation during exercise. The editors encourage researchers to refer to recently published guidelines on the use of sex and gender in cardiovascular research. [Extracted from the article]

The transitional epithelial cells (urothelium) that line the lumen of the urinary bladder form a barrier between potentially harmful pathogens, toxins, and other bladder contents and the inner layers of the bladder wall. The urothelium, however, is not simply a passive barrier, as it can produce signaling factors, such as ATP, nitric oxide, prostaglandins, and other prostanoids, that can modulate bladder function. We investigated whether substances produced by the urothelium could directly modulate the contractility of the underlying urinary bladder smooth muscle. Force was measured in isolated strips of mouse urinary bladder with the urothelium intact or denuded. Bladder strips developed spontaneous tone and phasic contractions. In urothelium-intact strips, basal tone, as well as the frequency and amplitude of phasic contractions, were 25%, 32%, and 338% higher than in urothelium-denuded strips, respectively. Basal tone and phasic contractility in urothelium-intact bladder strips were abolished by the cyclooxygenase (COX) inhibitor indomethacin (10 µM) or the voltage-dependent Ca2+ channel blocker diltiazem (50 µM), whereas blocking neuronal sodium channels with tetrodotoxin (1 µM) had no effect. These results suggest that prostanoids produced in the urothelium enhance smooth muscle tone and phasic contractions by activating voltage-dependent Ca2+ channels in the underlying bladder smooth muscle. We went on to demonstrate that blocking COX inhibits the generation of transient pressure events in isolated pressurized bladders and greatly attenuates the afferent nerve activity during bladder filling, suggesting that urothelial prostanoids may also play a role in sensory nerve signaling. NEW & NOTEWORTHY: This paper provides evidence for the role of urothelial-derived prostanoids in maintaining tone in the urinary bladder during bladder filling, not only underscoring the role of the urothelium as more than a barrier but also contributing to active regulation of the urinary bladder. Furthermore, cyclooxygenase products greatly augment sensory nerve activity generated by bladder afferents during bladder filling and thus may play a role in perception of bladder fullness. [ABSTRACT FROM AUTHOR]

In part 1 of this Perspective, I discussed general principles of scientific peer review in the biomedical sciences aimed at earlystage investigators (i.e., graduate students, postdoctoral fellows, and junior faculty). Here in part 2, I share my thoughts specifically on the topic of peer review of manuscripts. I begin by defining manuscript peer review and discussing the goals and importance of the concept. I then describe the organizational structure of the process, including the two distinct stages involved. Next, I emphasize several important considerations for manuscript reviewers, both general points and key considerations when evaluating specific types of papers, including original research manuscripts, reviews, methods articles, and opinion pieces. I then advance some practical suggestions for developing the written critique document, offer advice for making an overall recommendation to the editor (i.e., accept, revise, reject), and describe the unique issues involved when assessing a revised manuscript. Finally, I comment on how best to gain experience in the essential academic research skill of manuscript peer review. In part 3 of the series, I will discuss the topic of reviewing grant applications submitted to research funding agencies. [ABSTRACT FROM AUTHOR]

Animal models have been critical in building evidence that the prenatal experience and intrauterine environment are capable of exerting profound and permanent effects on metabolic health through developmental programming of obesity. However, despite physiological and evolutionary similarities, nonhuman primate models are relatively rare. The common marmoset monkey (Callithrix jacchus) is a New World monkey that has been used as a biomedical model for well more than 50 years and has recently been framed as an appropriate model for exploring early-life impacts on later health and disease. The spontaneous, multifactorial, and early-life development of obesity in the common marmoset make it a valuable research model for advancing our knowledge about the role of the prenatal and placental mechanisms involved in developmental programming of obesity. This paper provides a brief overview of obesity in the common marmoset, followed by a discussion of marmoset reproduction and placental characteristics. We then discuss the occurrence and utility of variable intrauterine environments in developmental programming in marmosets. Evidence of developmental programming of obesity will be given, and finally, we put forward future directions and innovations for including the placenta in developmental programming of obesity in the common marmoset. [ABSTRACT FROM AUTHOR]

As we approach the centenary of the term "comparative physiology," we reexamine its role in modern biology. Finding inspiration in Krogh's classic 1929 paper, we first look back to some timeless contributions to the field. The obvious and fascinating variation among animals is much more evident than is their shared physiological unity, which transcends both body size and specific adaptations. The "unity in diversity" reveals general patterns and principles of physiology that are invisible when examining only one species. Next, we examine selected contemporary contributions to comparative physiology, which provides the context in which reductionist experiments are best interpreted. We discuss the sometimes surprising insights provided by two comparative "athletes" (pronghorn and rattlesnakes), which demonstrate 1) animals are not isolated molecular mechanisms but highly integrated physiological machines, a single "rate-limiting" step may be exceptional; and 2) extremes in nature are rarely the result of novel mechanisms, but rather employ existing solutions in novel ways. Furthermore, rattlesnake tailshaker muscle effectively abolished the conventional view of incompatibility of simultaneous sustained anaerobic glycolysis and oxidative ATP production. We end this review by looking forward, much as Krogh did, to suggest that a comparative approach may best lend insights in unraveling how skeletal muscle stores and recovers mechanical energy when operating cyclically. We discuss and speculate on the role of the largest known protein, titin (the third muscle filament), as a dynamic spring capable of storing and recovering elastic recoil potential energy in skeletal muscle. [ABSTRACT FROM AUTHOR]

The diving physiology of aquatic animals at sea began 50 years ago with studies of the Weddell seal. Even today with the advancements in marine recording and tracking technology, only a few species are suitable for investigation. The first experiments were in McMurdo Sound, Antarctica. In this paper are examples of what was learned in Antarctica and elsewhere. Some methods employed relied on willingness of Weddell seals and emperor penguins to dive under sea ice. Diving depth and duration were obtained with a time depth recorder. Some dives were longer than an hour and as deep as 600 m. From arterial blood samples, lactate and nitrogen concentrations were obtained. These results showed how Weddell seals manage their oxygen stores, that they become reliant on a positive contribution of anaerobic metabolism during a dive duration of more than 20 min, and that nitrogen blood gases remain so low that lung collapse must occur at about 25 to 50 m. This nitrogen level was similar to that determined in elephant seals during forcible submersion with compression to depths greater than 100 m. These results led to further questions about diving mammal's terminal airway structure in the lungs. Much of the strengthening of the airways is not for avoiding the "bends," by enhancing lung collapse at depth, but for reducing the resistance to high flow rates during expiration. The most exceptional examples are the small whales that maintain high expiratory flow rates throughout the entire vital capacity, which represents about 90% of their total lung capacity. [ABSTRACT FROM AUTHOR]

Neuronal stimulation by light is a novel approach in the emerging field of optogenetics, where genetic engineering is used to introduce light-activated chan-nels. However, light is also capable of stimulating neurons even in the absence of genetic modifications through a range of physical and biological mechanisms. As a result, rigorous design of optogenetic experiments needs to take note of alterna-tive and parallel effects of light illumination of neuronal tissues. Thus all matters relating to light penetration are critical to the development of studies using light-activated proteins. This paper discusses ways to quantify light, light penetra-tion in tissue, as well as light stimulation of neurons in physiological conditions. We also describe the direct effect of light on neurons investigated at different sites. [ABSTRACT FROM AUTHOR]