Alterations in vasodilator-stimulated phosphoprotein (VASP) phosphorylation: associations with asthmatic phenotype, airway inflammation and β(2)-agonist use

BACKGROUND: Vasodilator-stimulated phosphoprotein (VASP) mediates focal adhesion, actin filament binding and polymerization in a variety of cells, thereby inhibiting cell movement. Phosphorylation of VASP via cAMP and cGMP dependent protein kinases releases this "brake" on cell motility. Thus, phosphorylation of VASP may be necessary for epithelial cell repair of damage from allergen-induced inflammation. Two hypotheses were examined: (1) injury from segmental allergen challenge increases VASP phosphorylation in airway epithelium in asthmatic but not nonasthmatic normal subjects, (2) regular in vivo β(2)-agonist use increases VASP phosphorylation in asthmatic epithelium, altering cell adhesion. METHODS: Bronchial epithelium was obtained from asthmatic and non-asthmatic normal subjects before and after segmental allergen challenge, and after regularly inhaled albuterol, in three separate protocols. VASP phosphorylation was examined in Western blots of epithelial samples. DNA was obtained for β(2)-adrenergic receptor haplotype determination. RESULTS: Although VASP phosphorylation increased, it was not significantly greater after allergen challenge in asthmatics or normals. However, VASP phosphorylation in epithelium of nonasthmatic normal subjects was double that observed in asthmatic subjects, both at baseline and after challenge. Regularly inhaled albuterol significantly increased VASP phosphorylation in asthmatic subjects in both unchallenged and antigen challenged lung segment epithelium. There was also a significant increase in epithelial cells in the bronchoalveolar lavage of the unchallenged lung segment after regular inhalation of albuterol but not of placebo. The haplotypes of the β(2)-adrenergic receptor did not appear to associate with increased or decreased phosphorylation of VASP. CONCLUSION: Decreased VASP phosphorylation was observed in epithelial cells of asthmatics compared to nonasthmatic normals, despite response to β-agonist. The decreased phosphorylation does not appear to be associated with a particular β(2)-adrenergic receptor haplotype. The observed decrease in VASP phosphorylation suggests greater inhibition of actin reorganization which is necessary for altering attachment and migration required during epithelial repair

Caspase-3 dependent nitrergic neuronal apoptosis following cavernous nerve injury is mediated via RhoA and ROCK activation in major pelvic ganglion

Axonal injury due to prostatectomy leads to Wallerian degeneration of the cavernous nerve (CN) and erectile dysfunction (ED). Return of potency is dependent on axonal regeneration and reinnervation of the penis. Following CN injury (CNI), RhoA and Rho-associated protein kinase (ROCK) increase in penile endothelial and smooth muscle cells. Previous studies indicate that nerve regeneration is hampered by activation of RhoA/ROCK pathway. We evaluated the role of RhoA/ROCK pathway in CN regulation following CNI using a validated rat model. CNI upregulated gene and protein expression of RhoA/ROCK and caspase-3 mediated apoptosis in the major pelvic ganglion (MPG). ROCK inhibitor (ROCK-I) prevented upregulation of RhoA/ROCK pathway as well as activation of caspase-3 in the MPG. Following CNI, there was decrease in the dimer to monomer ratio of neuronal nitric oxide synthase (nNOS) protein and lowered NOS activity in the MPG, which were prevented by ROCK-I. CNI lowered intracavernous pressure and impaired non-adrenergic non-cholinergic-mediated relaxation in the penis, consistent with ED. ROCK-I maintained the intracavernous pressure and non-adrenergic non-cholinergic-mediated relaxation in the penis following CNI. These results suggest that activation of RhoA/ROCK pathway mediates caspase-3 dependent apoptosis of nitrergic neurons in the MPG following CNI and that ROCK-I can prevent post-prostatectomy ED

Masturbación femenina y masculina en adulto joven: beneficios y tabúes

Curso de Especial Interés: Psicología y SexualidadEste trabajo muestra una revisión teórica sobre la importancia de la masturbación en la vida del ser humano, abordando algunas de las posturas que existen y teniendo en cuenta que hay muchos prejuicios y tabúes al momento de mencionar este tema. Se encontró que la mayoría de los participantes tienen un conocimiento previo sobre el tema.RESUMEN JUSTIFICACIÓN 1. DESARROLLO DE LA INFORMACIÓN 2. METODOLOGÍA 3. ESTUDIO DE MERCADEO 4. RESULTADOS 5. CONCLUSIONES REFERENCIASPregradoPsicólog

Role of Rho -kinase -dependent constrictor activity in vascular smooth muscle.

Vascular tone is modulated by hormonal, neural and paracrine input for the proper regulation of blood pressure and organ perfusion. Elucidating and understanding the signaling pathway(s) involved in vascular smooth muscle contraction may aid in the prevention or successful treatment of many vascular-related end organ pathologies. Contraction of the smooth muscle cell occurs primarily via the Ca2+-dependent stimulation of myosin light chain (MLC) kinase, to lead to the phosphorylation of MLC and subsequent actin/myosin interaction. The phosphorylation of MLC is also regulated by the activity of MLC phosphatase, a process termed Ca2+-sensitization. MLC phosphatase activity is, in part, regulated by the small G-protein, RhoA, and a downstream target, Rho-kinase. The serine/threonine kinase, Rho-kinase, phosphorylates the myosin binding subunit of MLC phosphatase to inhibit phosphatase activity and thus promote the phosphorylated state of MLC. The goal of this dissertation was to determine the physiologic role and regulation of RhoA/Rho-kinase activity in vascular smooth muscle, following the general hypothesis that increased Rho-kinase activity promotes the maintenance of vasoconstriction and the inhibition of Rho-kinase signaling mediates vasodilation. Western blot analysis demonstrated RhoA and Rho-kinase protein expression in isolated rat cavernosal tissue. Using an in vivo rat model of erection, the intracavernosal injection of Y-27632, a selective Rho-kinase inhibitor, was found to result in a significant increase in intracavernosal pressure/mean arterial pressure. In vitro measurements of isometric force generation demonstrated Y-27632 to relax agonist-induced contraction of isolated rat cavernosal tissue and aorta. Additional measurements of isometric force generation of rat aorta found the inhibitory effects of Y-27632 to be attenuated in the absence of nitric oxide production or signaling, consistent with the hypothesis that Rho-kinase activity is elevated in the absence of nitric oxide. Data presented in this dissertation demonstrate a role for Rho-kinase activity in the maintenance of vascular smooth muscle contraction and provide evidence to support that the inhibition of Rho-kinase activity is a physiologic mechanism of nitric oxide-induced vasodilation.Ph.D.Animal PhysiologyBiological SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/131555/2/3057921.pd