Effects of FRG-8701 on gastric acid secretion, gastric mucosal lesions by necrotizing agents and experimental gastric or duodenal ulcer in rats

Multitargeting in cardioprotection: An example of biaromatic compounds

A multitarget drug design approach is actively developing in modern medicinal chemistry and pharmacology, especially with regard to multifactorial diseases such as cardiovascular diseases, cancer, and neurodegenerative diseases. A detailed study of many well-known drugs developed within the single-target approach also often reveals additional mechanisms of their real pharmacological action. One of the multitarget drug design approaches can be the identification of the basic pharmacophore models corresponding to a wide range of the required target ligands. Among such models in the group of cardioprotectors is the linked biaromatic system. This review develops the concept of a "basic pharmacophore" using the biaromatic pharmacophore of cardioprotectors as an example. It presents an analysis of possible biological targets for compounds corresponding to the biaromatic pharmacophore and an analysis of the spectrum of biological targets for the five most known and most studied cardioprotective drugs corresponding to this model, and their involvement in the biological effects of these drugs.

Role of nitric oxide and prostaglandin in the protective effect of pibutidine hydrochloride, a novel histamine H2-receptor antagonist, on the gastric mucosal lesions in rats

1. The role of endogenous nitric oxide (NO) and prostaglandins (PGs) in the gastric mucosal protective action of pibutidine hydrochloride (IT-066), a novel histamine H2-receptor antagonist, was investigated in a 0.15 N hydrochloride (HCl) + 60% ethanol (EtOH)-induced gastric lesion model. 2. The 0.15 N HCl + 60% EtOH-induced lesion formation was reduced significantly by IT-066 (3 mg/kg, PO), NOR3 (spontaneous NO releaser; 0.03-0.1 mg/kg, SC) or PGE2 (0.01 mg/kg, PO) but was not reduced by famotidine (1-10 mg/kg, PO). 3. Pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) (3 mg/kg, IV), an inhibitor of NO synthase, inhibited the protective action of IT-066 (3 mg/kg, PO), and the inhibitory effect of L-NAME was reversed by L-arginine (300 mg/kg, IV). The protective effect of PGE2 (0.01 mg/kg, PO) was not affected by the pretreatment with L-NAME (3 mg/kg, IV). 4. Infusion of carboxy-PTIO (1 mg/kg/min), a direct NO scavenger, inhibited the protective effect of IT-066 (3 mg/kg, SC) or NOR3 (0.1 mg/kg, SC). Pretreatment with indomethacin (5 mg/kg, SC) markedly reduced the protective effect of IT-066 (3 mg/kg, PO) or NOR3 (0.1 mg/kg, SC). 5. These results suggest that endogenous NO and PGs may be implicated in the gastric mucosal protection induced by IT-066 and that the endogenous PGs may contribute to the protective effect of NO.

Pharmacology of JB-9315, a new selective histamine H2-receptor antagonist

1. The histamine H2-receptor antagonistic activity and antisecretory and antiulcer effects of JB-9315 were studied in comparison with the standard H2 blocker ranitidine. 2. In vitro, JB-9315 is a competitive antagonist of histamine H2 receptors in the isolated, spontaneously beating guinea-pig right atrium, with a pA2 value of 7.30 relative to a value of 7.36 for ranitidine. JB-9315 was specific for the histamine H2 receptor because, at high concentration, it did not affect histamine- or acetylcholine-induced contractions in guinea-pig isolated ileum or rat isolated duodenum, respectively. 3. JB-9315 dose dependently inhibited histamine-, pentagastrin- or carbachol-stimulated acid secretion and basal secretion in the perfused stomach preparation of the anesthetized rat. In the pylorus-ligated rat after intraperitoneal administration, total acid output over 4 h was inhibited by JB-9315 with an ID50 of 32.8 mg/kg, confirming its H2-receptor antagonist properties. 4. JB-9315 showed antiulcer activity against cold stress plus indomethacin-induced lesions with an ID50 of 6.8 mg/kg. 5. JB-9315, 50 and 100 mg/kg, inhibited macroscopic gastric hemorrhagic lesions induced by ethanol. In contrast, ranitidine (50 mg/kg) failed to reduce these lesions. 6. These results indicate that JB-9315 is a new antiulcer drug that exerts a cytoprotective effect in addition to its gastric antisecretory activity.

JB-9322, a new selective histamine H2-receptor antagonist with potent gastric mucosal protective properties

1. JB-9322 is a selective histamine H2-receptor antagonist with gastric antisecretory activity and mucosal protective properties. 2. The affinity of JB-9322 for the guinea-pig atria histamine H2-receptor was approximately 2 times greater than that of ranitidine. 3. In vivo, the ID50 value for the inhibition of gastric acid secretion in pylorus-ligated rats was 5.28 mg kg-1 intraperitoneally. JB-9322 also dose-dependently inhibited gastric juice volume and pepsin secretion. In gastric lumen-perfused rats, intravenous injection of JB-9322 dose-dependently reduced histamine-, pentagastrin- and carbachol-stimulated gastric acid secretion. 4. JB-9322 showed antiulcer activity against aspirin and indomethacin-induced gastric lesions and was more potent than ranitidine. 5. JB-9322 effectively inhibited macroscopic gastric haemorrhagic lesions induced by ethanol. Intraperitoneal injection was effective in preventing the lesions as well as oral treatment. The oral ID50 value for these lesions was 1.33 mg kg-1. By contrast, ranitidine (50 mg kg-1) failed to reduce these lesions. In addition, the protective effect of JB-9322 was independent of prostaglandin synthesis. 6. These results indicate that JB-9322 is a new antiulcer drug that exerts a potent cytoprotective effect in addition to its gastric antisecretory activity.