Antihypertensive, antiatherosclerotic, and plasma lipid-lowering effects of monatepil, a novel calcium antagonist with alpha 1-adrenoceptor-blocking activity in experimental animals

Influence of halogen size on the supramolecular and energy landscape of the THF solvates of the halogen derivatives of dianthranilide

The detailed description of the crystal structure of the THF solvates of four halogen derivatives of dianthranilide has been reported.

Asp125 and Thr130 in transmembrane domain 3 are major sites of alpha1b-adrenergic receptor antagonist binding

Site-directed mutagenesis was used to investigate the molecular interactions involved in prazosin binding to the human alpha(1b)-adrenergic receptor (alpha(1b)-AR) receptor. Based on molecular modeling studies, Thr130 and Asp125 in transmembrane region III of the alpha(1b)-AR receptor were found to interact with prazosin. Thr130 and Asp125 were mutated to alanine (Ala) and expressed in HEK293 cells. The radioligand [(3)H]prazosin did not show any binding to Asp125Ala mutant of alpha(1b)-AR. Therefore, it was not possible to find any prazosin affinity to the mutant using the radioligand [(3)H]prazosin. The mutation also abolished phenylephrine-stimulated inositol phosphate (IP) formation of [(3)H]myo-inositol. On the other hand, the Thr130Ala mutant showed reduced binding affinity for [(3)H]prazosin (dissociation constant, K(d) 674.27 pM versus 90.27 pM for the wild-type receptor) and had reduced affinity for both tamsulosin and prazosin (11-fold and 9-fold, respectively). However, the Thr130Ala mutant receptor retained the ability to stimulate the formation of [(3)H]myo-inositol. The results provide direct evidence that Asp125 and Thr130 are responsible for the interactions between alpha(1b)-AR receptor and radioligand [(3)H]prazosin as well as tamsulosin.

Induction of chymase that forms angiotensin II in the monkey atherosclerotic aorta

Chymase shows a catalytic efficiency in the formation of angiotensin (Ang) II. In the present study, the characterization and primary structure of monkey chymase were determined, and the pathophysiological role of chymase was investigated on the atherosclerotic monkey aorta. Monkey chymase was purified from cheek pouch vascular tissue using heparin affinity and gel filtration columns. The enzyme rapidly converted Ang I to Ang II (Km = 98 microM, k(cat) = 6203/min) but did not degrade several peptide hormones such as Ang II, substance P, vasoactive intestinal peptide and bradykinin. The primary structure, which was deduced from monkey chymase cDNA, showed a high homology to that of human chymase (98%). The mRNA levels of the aorta chymase were significantly increased in the atherosclerotic aorta of monkeys fed a high-cholesterol diet. These results indicate that monkey chymase has a highly specific Ang II-forming activity and may be related to the pathogenesis of atherosclerosis.