Viagra: Difference between revisions
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Viagra is the trademark name for the drug sildenafil, which was developed by the pharmaceutical company Pfizer. It is used to treat erectile dysfunction in males.<ref>Francis, Sharron H., Corbin, Jackie D. (2005). Sildenafil: efficacy, safety, tolerability and mechanism of action in treating erectile dysfunction. Expert opinion on drug metabolism &amp;amp; toxicology. 1 (2), p283-293.</ref> | Viagra is the trademark name for the drug sildenafil, which was developed by the pharmaceutical company Pfizer. It is used to treat erectile dysfunction in males.<ref>Francis, Sharron H., Corbin, Jackie D. (2005). Sildenafil: efficacy, safety, tolerability and mechanism of action in treating erectile dysfunction. Expert opinion on drug metabolism &amp;amp;amp; toxicology. 1 (2), p283-293.</ref> | ||
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==== Mechanism of action ==== | ==== Mechanism of action ==== | ||
<span style="line-height: 1.5em;">[[Acetylcholine|Acetylcholine]] is released by nerves in the walls of penile blood vessels which causes nitric oxide (NO) to be released by endothelial cells in the vessel lining. NO binds to the enzyme [[Guanylyl cyclase|guanylyl cyclase]] in the smooth muscle cells of the blood vessel which catalyses the production of [[CGMP|cyclic GMP]] (cGMP) from [[GTP|GTP]]. The smooth muscle cells respond to this by relaxing | <span style="line-height: 1.5em;">[[Acetylcholine|Acetylcholine]] is released by nerves in the walls of penile blood vessels which causes nitric oxide (NO) to be released by endothelial cells in the vessel lining. NO binds to the enzyme [[Guanylyl cyclase|guanylyl cyclase]] in the smooth muscle cells of the blood vessel which catalyses the production of [[CGMP|cyclic GMP]] (cGMP) from [[GTP|GTP]]. The smooth muscle cells respond to this by relaxing which allows the blood vessel to dilate.</span> | ||
cGMP is quickly degraded by cGMP phosphodiesterase. This enzyme hydrolyses cGMP to GMP. Viagra works to [[Competitive inhibitors|competitively inhibit]] cGMP phosphodiesterase so that [[Intracellular|intracellular]] levels of cGMP remain high, meaning penile blood vessels are dilated for a longer period of time.<ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science. p888-889.</ref><br> | cGMP is quickly degraded by cGMP phosphodiesterase. This enzyme hydrolyses cGMP to GMP. Viagra works to [[Competitive inhibitors|competitively inhibit]] cGMP phosphodiesterase so that [[Intracellular|intracellular]] levels of cGMP remain high, meaning penile blood vessels are dilated for a longer period of time.<ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science. p888-889.</ref><br> | ||
Revision as of 23:14, 16 November 2013
Viagra is the trademark name for the drug sildenafil, which was developed by the pharmaceutical company Pfizer. It is used to treat erectile dysfunction in males.[1]
Mechanism of action
Acetylcholine is released by nerves in the walls of penile blood vessels which causes nitric oxide (NO) to be released by endothelial cells in the vessel lining. NO binds to the enzyme guanylyl cyclase in the smooth muscle cells of the blood vessel which catalyses the production of cyclic GMP (cGMP) from GTP. The smooth muscle cells respond to this by relaxing which allows the blood vessel to dilate.
cGMP is quickly degraded by cGMP phosphodiesterase. This enzyme hydrolyses cGMP to GMP. Viagra works to competitively inhibit cGMP phosphodiesterase so that intracellular levels of cGMP remain high, meaning penile blood vessels are dilated for a longer period of time.[2]
References
- ↑ Francis, Sharron H., Corbin, Jackie D. (2005). Sildenafil: efficacy, safety, tolerability and mechanism of action in treating erectile dysfunction. Expert opinion on drug metabolism &amp;amp; toxicology. 1 (2), p283-293.
- ↑ Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science. p888-889.