Physiological Properties of the Lower Urinary Tract
Anthony R. Mundy, John M. Fitzpatrick, David E. Neal, Nicholas J. R. George in The Scientific Basis of Urology, 2010
Urethral smooth muscle exhibits spontaneous electrical and mechanical activity that contributes to the overall muscular tone. Electrical activity occurs because of bursts of spikes superimposed on a slower more rhythmic activity, and could be initiated by autonomic transmitters (205). Two types of Ca2+ currents—L type and T type—have been recorded in isolated myocytes. Blockade of the former type reduced the number of spikes in each burst; the frequency within bursts was attenuated by blockade of T-type current (206). However, both channels represent targets that may modulate spontaneous activity. The muscle cells are closely associated with interstitial cells that may at least modify their activity (207). The observation that interstitial cells are closely associated with NOS synthase–containing nerves suggests that they may be intermediaries between nerves and urethral smooth muscle (208).
Principles of Pathophysiology of Infertility Assessment and Treatment*
Asim Kurjak in Ultrasound and Infertility, 2020
The functions of the testis are spermatogenesis, which takes place in the germinal epithelium of seminiferous tubules and steroidogenesis, which takes place in the interstitial cells (Leydig). The regulation of testicular function is controlled by an interaction between the CNS, hypothalamus, hypophysis, and testis. The spermatogenesis in man requires a period of 70 ± 5 d. The passage of sperm through the epididymis and vas deferens varies with the mean time of 12 d. It is not a single process of transport, but it is vital to allow further sperm maturation and development of sperm motility. The process of ejaculation is controlled by the nervous system and involves the secretion of prostate, testicular, and seminal vesicular components.
Urinary System
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
Focal mononuclear inflammatory cell infiltrates are noted extremely commonly as clusters within the interstitium of the renal cortex and less commonly in the medulla of rodents, dogs, and monkeys. These are most often of no toxicologic significance, unless they are accompanied by degenerative tubular or glomerular changes and/or show significant dose response in incidence or severity. The number of inflammatory cell foci increases in these spontaneous lesions with age and are often associated with the presence of CPN and other chronic kidney lesions in rodents. These focal to multifocal cellular aggregates most often consist of lymphocytes, but may be admixed with macrophages or small numbers of plasma cells or neutrophils. Interstitial inflammation may occur in toxicologic studies with agents that affect several components within the interstitial extracellular matrix, including those associated with antibodies against the basement membrane as well as drugs that affect interstitial cells.
Urothelium removal does not impact mucosal activity in response to muscarinic or adrenergic receptor stimulation
Published in Tissue Barriers, 2023
Christian Moro, Charlotte Phelps
A diverse collection of cells also resides within the lamina propria, which may induce the contractile activity of this layer. These include connective tissue, blood vessels, and afferent nerve fibers, as well as a range of cells types which include interstitial cells and fibroblasts.35 Additionally, a variety of immune cells are present in the lamina propria, such as mast cells and dendritic cells.36,37 Within this layer, the interstitial cells most likely mediate contractile activity and the responses to receptor activation. It is understood that these cells have the ability to contract and hold close associations with the calcium transients and spontaneous activity.26 Interstitial cells have also previously been suggested as the cell type mediating urothelial/lamina propria contractions in response to neurokinin-A.38 Therefore, it appears from past research that the interstitial cells are likely modulators for the observed responses demonstrated in strips of urothelium-removed lamina propria.
Crataegus aronia enhances sperm parameters and preserves testicular architecture in both control and non-alcoholic fatty liver disease-induced rats
Published in Pharmaceutical Biology, 2018
Testosterone, which is crucial for spermatogenesis, is synthesized and secreted by the interstitial cells of Leydig in the testes following stimulation by LH (Blanco-Rodriguez and Martinez-Garcia 1998). In addition, FSH acts within the tubules to elevate the number and function of Sertoli cells, which facilitate the progression of germ cells to spermatozoa and indirectly regulate spermatogenesis (Eleawa et al. 2014). In the current study, the administration of C. aronia to control rats for 4 weeks significantly elevated epididymal weights and serum levels of testosterone, FSH and LH, without altering oestradiol level. This was associated with the normal sperm total abnormality percentage and significant increases in sperm count and motility, as well as an increased number of pups at birth. In addition, less time was needed for cohabitation. Preserved testicular structure, seminiferous tubules and germ cell morphologies were observed in this group of rats.
Reproductive toxicity of melamine against male mice and the related mechanism
Published in Toxicology Mechanisms and Methods, 2018
Jian Huang, Guozhen Yang, Fengqiong Xia, Shu Zhang
Male hormones are mainly testosterone, together with small amounts of dehydroepiandrosterone and androstenetrione. Testosterone is mainly secreted by testicular interstitial cells, which is regulated by the hypothalamic–pituitary–testicular axis. Moreover, the testicular activity is also self-regulated through negative feedback regulation, so the testicular endocrine activity can be maintained at a stable level (Chang et al. 2014). Surprisingly, the serum testosterone levels of exposure groups herein significantly rose. Probably, the low testosterone level in testicles induced reduction in the serum level, thus up-regulating serum luteinizing hormone (LH) level through negative feedback. LH exerted effects on LH receptor in testicular interstitial cells to promote testosterone secretion, so its level was then augmented in serum.
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