Improvement in muscular strength and aerobic capacities in elderly people occurs independently of physical training type or exercise model

OBJECTIVES: Progressive decline of physiological processes with aging is normal. Aging is also associated with decreased functional capacity and onset of many diseases. This study evaluated the changes in physical fitness (PF), body composition (BC), and lipid profile (LP) in elderly men completing different training protocols. METHODS: Fifty-five men (age 60-80 years) were randomized into the following groups: without training, aerobic training on dry land, combined training on dry land, and combined training in water. Training was conducted for 8 weeks, and PF, LP, and BC were assessed at the beginning and end of the intervention. RESULTS: Significant improvements were observed in all parameters; however, combined programs on land or in water were more effective at improving strength and aerobic fitness. Combined exercise produced greater effects on BC and LP and some muscle fitness parameters; however, improvements in muscular and aerobic capacities occurred independently of exercise type or model. CONCLUSION: These results indicate that the effects of training occur regardless of training type or model, and are directly associated with training periodization, adherence, and regularit

Signal transduction underlying the control of urinary bladder smooth muscle tone by muscarinic receptors and β-adrenoceptors

The normal physiological contraction of the urinary bladder, which is required for voiding, is predominantly mediated by muscarinic receptors, primarily the M3 subtype, with the M2 subtype providing a secondary backup role. Bladder relaxation, which is required for urine storage, is mediated by β-adrenoceptors, in most species involving a strong β3-component. An excessive stimulation of contraction or a reduced relaxation of the detrusor smooth muscle during the storage phase of the micturition cycle may contribute to bladder dysfunction known as the overactive bladder. Therefore, interference with the signal transduction of these receptors may be a viable approach to develop drugs for the treatment of overactive bladder. The prototypical signaling pathway of M3 receptors is activation of phospholipase C (PLC), and this pathway is also activated in the bladder. Nevertheless, PLC apparently contributes only in a very minor way to bladder contraction. Rather, muscarinic-receptor-mediated bladder contraction involves voltage-operated Ca2+ channels and Rho kinase. The prototypical signaling pathway of β-adrenoceptors is an activation of adenylyl cyclase with the subsequent formation of cAMP. Nevertheless, cAMP apparently contributes in a minor way only to β-adrenoceptor-mediated bladder relaxation. BKCa channels may play a greater role in β-adrenoceptor-mediated bladder relaxation. We conclude that apart from muscarinic receptor antagonists and β-adrenoceptor agonists, inhibitors of Rho kinase and activators of BKCa channels may have potential to treat an overactive bladder

Generation of slow waves in the antral region of guinea-pig stomach - a stochastic process

Slow waves were recorded from the circular muscle layer of the antral region of guinea-pig stomach. Slow waves were abolished by 2APB, an inhibitor of IP3-induced Ca2+ release.When the rate of generation of slow waves was monitored it was found to vary from cycle to cycle around a mean value. The variation persisted after abolishing neuronal activity with tetrodotoxin.When simultaneous recordings were made from interstitial cells in the myenteric region (ICCMY) and smooth muscle cells of the circular layer, variations in the rate of generation of slow waves were found to be linked with variations in the rate of generation of driving potentials by ICCMY.A preparation was devised which consisted of the longitudinal muscle layer and ICCMY. In this preparation ICCMY and smooth muscle cells lying in the longitudinal muscle layer generated driving potentials and follower potentials, synchronously.Driving potentials had two components, a rapid primary component that was followed by a prolonged plateau component. Caffeine (3 mM) abolished the plateau component; conversely reducing the external concentration of calcium ions [Ca2+]o mainly affected the primary component.Analysis of the variations in the rate of generation of driving potentials indicated that this arose because both the duration of individual driving potentials and the interval between successive driving potentials varied.It is suggested that the initiation of pacemaker activity in a network of ICCMY is a stochastic process, with the probability of initiating a driving potential slowly increasing, after a delay, from a low to a higher value following the previous driving potential