Antinociceptive activity of sildenafil and adrenergic agents in the writhing test in mice.
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The authors investigated the antinociceptive activity of sildenafil and adrenergic agents co-administered in the writhing test in mice. The intensity of nociception was quantified by the number of writhes occurring between 0 and 30 min after stimulus injection. Nontreated groups (NT) received acid intraperitoneally (ip) followed by sterile saline (ip). Animals received (ip) sildenafil (2.5 or 5 mg/kg), propranolol (0.5 or 2 mg/kg), atenolol (0.05 or 2 mg/kg), prazosin (0.05 or 0.25 mg/kg) or clonidine (0.01 or 0.1 mg/kg) 30 min before acid injection. It was observed that only the largest doses of every drug inhibited the number of writhes in mice. In another series of experiments, animals were pretreated with the lower ineffective doses of propranolol, atenolol, prazosin or clonidine. After 30 min, mice also received the lower ineffective dose of sildenafil followed by acid injection. The combination of ineffective doses of propranolol, atenolol, prazosin or clonidine with sildenafil significantly inhibited the nociceptive response induced by acetic acid injection. Data obtained from these experiments showed that ineffective doses of sildenafil associated with ineffective doses of adrenergic agents provided analgesic effects in the writhing test. (+info)
Superoxide from NADPH oxidase upregulates type 5 phosphodiesterase in human vascular smooth muscle cells: inhibition with iloprost and NONOate.
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Determination of a new type of phosphodiesterase-5 inhibitor, thioquinapiperifil, in a dietary supplement promoted for sexual enhancement.
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A new type of phosphodiesterase-5 (PDE-5) inhibitor, thioquinapiperifil (1), was found in dietary supplements. LC-MS analysis indicated that the supplements contain two major compounds. One was identified as thiodenafil (synonym: thiosildenafil) by direct comparison with the authentic compound. The other showed a molecular weight of 448, and accurate mass measurement showed its elemental composition to be C(24)H(28)N(6)O(1)S(1). Together, the mass and NMR spectrometric data revealed that the compound is an imidazoquinazoline derivative: 3-ethyl-1,3-dihydro-8-[[[2-[4-(hydroxymethyl)-1-piperidinyl]phenyl]methyl]amino]- 2H-imidazo[4,5-g]quinazoline-2-thione. This compound had been synthesized as a PDE-5 inhibitor, formerly reported as KF31327 by Kyowa Hakko Kogyo Co., Ltd. Considering this compound's general properties, it has been renamed thioquinapiperifil with the agreement of Kyowa Hakko Kogyo Co., Ltd. The detection of imidazoquinazoline-type compounds in dietary supplements has not been reported. Quantitative analysis showed that the contents of 1 and thiodenafil in the products were about 13-15 mg/tablet (43-48 microg/mg) and about 0.4 mg/tablet (1 microg/mg), respectively. (+info)
Expression, activity, and pro-hypertrophic effects of PDE5A in cardiac myocytes.
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H2S-donating sildenafil (ACS6) inhibits superoxide formation and gp91phox expression in arterial endothelial cells: role of protein kinases A and G.
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