@article {Abdel Aziz:April 2007:0303-4569:66,
	author = "Abdel Aziz, M. T.",
	author = "Mostafa, T.",
	author = "Atta, H.",
	author = "Rashed, L.",
	author = "Marzouk, S. A.",
	author = "Obaia, E. M.",
	author = "Sabry, D.",
	author = "Hassouna, A. A.",
	author = "El-Shehaby, A. M.",
	author = "Abdel Aziz, A.T.",
	title = "Oral phosphodiesterase-5 inhibitors: effect of heme oxygenase inhibition on cGMP signalling in rat cavernous tissue",
	journal = "Andrologia",
	volume = "39",
	year = "April 2007",
	abstract = "Summary <P></P>This work postulated that heme oxygenase (HO) is partly responsible for controlling phosphodiesterase-5 inhibitor actions by modulating cyclic guanosine monophosphate (cGMP) cavernous tissue levels. Five hundred and four male Sprague-Dawley rats, divided into five groups, were investigated. Group 1 (<I>n</I>&#8201;=&#8201;72) included controls, group 2 (<I>n</I>&#8201;=&#8201;72) received sildenafil citrate (Viagra<SUP>R</SUP>) orally, group 3 (<I>n</I>&#8201;=&#8201;72) received vardenafil hydrochloride (Levitra<SUP>R</SUP>), group 4 (<I>n</I>&#8201;=&#8201;72) received tadalafil (Cialis<SUP>R</SUP>). Group 5 (<I>n</I>&#8201;=&#8201;216), subdivided into three subgroups (A, B and C, 72 each), received the same dose of each drug with the HO inhibitor, Zn protoporphyrin. Eight rats from each group/subgroup were killed at 0.5, 1, 2, 3, 4, 6, 18, 24 and 36&#8201;h when cGMP levels in the cavernous tissues were estimated. Cavernous tissue cGMP levels increased significantly in sildenafil, vardenafil and tadalafil-treated rats compared to the controls with significant decreases after HO inhibition. It is concluded that the effects of these PDE-5 inhibitors in rat cavernous tissue are partly mediated through HO activity via the cGMP signalling pathway.",
	pages = "66-70(5)",
	url = "http://www.ingentaconnect.com/content/bsc/and/2007/00000039/00000002/art00005"
	doi = "doi:10.1111/j.1439-0272.2007.00765.x"
}