Medizinische Chemie

Objective: Sildenafil is a selective inhibitor of phosphodiesterase 5 (PDE5) and is the first agent with this mode of action for the treatment of male erectile dysfunction. There has recently been an explosion of interest in sexual dysfunction. Erectile dysfunction (ED) is defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual activity. This article aims to discuss in details the commercial synthesis of Sildenafil as published by the Pfizer research group and describe critically the role of Sildenafil in diabetic neuropathic patients with erectile dysfunction.
Method: A computer as well as manual search was made to collect the relevant data published in various peer-reviewed journals on ViagraTM.
Results: The synthesis of Sildenafil serves as an excellent example of the demands of commercial chemistry. Also, the serendipitous discovery of this drug's positive effect on sexual performance has revolutionized the management of erectile dysfunction. Although the literature is spare, Tadalafil has a longer half-life than Sildenafil and therefore may be recommended as the choice of preference. Contraindications for their use include the use of nitrates, unstable angina, recent myocardial infarction or complicated congestive heart failure (CHF). Other oral agents including apomorphine, Phentolamine and trazodone have also been proposed to treat ED with some adverse effects.
Conclusion: Our data in this review portrays accurately using Sildenafil for restoring sexual functions in diabetic neuropathic population. Other limitations include a great potential for misuse and costly.

Type 2 taste receptors (TAS2Rs), a large family of GPCRs, were first discovered in the gustatory system, and are co-expressed in a subset of taste receptor cells and detect bitter-tasting compounds. Type 1 taste receptors (TAS1R3) function as an obligate partner for both the umami receptor and the sweet receptor. Recently, it has become clear that taste receptors are also expressed outside the gustatory system. Here, with Tas2r5-Cre/GFP and Tas1r3-Cre/GFP transgenic mice, the expression of taste receptors (Tas1r3 or Tas2r5) is observed in serous gland and mucous gland of tongue. Taste signal transduction cascade (Gnat3 and PLC-β2) is also detected in serous gland and mucous gland of tongue. After DTA expression in Tas2r5+ and Tas1r3+ cells, the expression of taste receptors and taste signal transduction cascade is ablated in serous and mucous gland of tongue.

In mammalian tongue, all the compartments of the lingual epithelium are turned over throughout adult life. There is a continual requirement for proliferation to replace cells lost by differentiation within each compartment. In contrast to remarkably elucidating to the molecular basis for taste perception, too little is known about the mechanism of lingual epithelium and papillae. In this article, we briefly summarize what is known about the different stem cell compartments in lingual epithelium and papillae, and discuss the evidence for existence of stem cell in lingual epithelium and taste bud. We then consider a new model of homeostasis in lingual epithelium and papillae, in which tissue maintenance depends on multiple-stem cell population. Problems revealed by the application of epigenetic marker are also discussed.