Endothelins are a newly described peptide family consisting of three peptides (ET-1, ET-2 and ET-3) which are the most potent vasoconstrictive peptides known. They are crucial in the regulation of vascular smooth muscle tone. The diverse functions of endothelins are thought to be mediated by interaction with many different receptors coupled to the inositol phosphate/calcium ion messenger pathway. However, because of the structural resemblance of the three peptides, the presence and nature of multiple endothelin receptors remain to be elucidated. We report here the cloning of a complementary DNA encoding a bovine endothelin receptor, which has a transmembrane topology similar to that of other G protein-coupled receptors and shows specific binding, with the highest selectivity to ET-1 in animal cells transfected with the cloned cDNA. This receptor messenger RNA is widely distributed in the central nervous system and peripheral tissues, particularly in the heart and lung. Our results support the view that there are other receptor subtypes.

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Summary Purpose KCNQ2 mutations have been found in patients with benign familial neonatal seizures, myokymia, or early onset epileptic encephalopathy (EOEE). In this study, we aimed to delineate the clinical spectrum of EOEE associated with KCNQ2 mutation. Methods A total of 239 patients with EOEE, including 51 cases with Ohtahara syndrome and 104 cases with West syndrome, were analyzed by high‐resolution melting (HRM) analysis or whole‐exome sequencing. Detailed clinical information including electroencephalography (EEG) and brain magnetic resonance imaging (MRI) were collected from patients with KCNQ2 mutation. Key Findings A total of nine de novo and one inherited mutations were identified (two mutations occurred recurrently). The initial seizures, which were mainly tonic seizures, occurred in the early neonatal period in all 12 patients. A suppression‐burst pattern on EEG was found in most. Only three patients showed hypsarrhythmia on EEG; eight patients became seizure free when treated with carbamazepine, zonisamide, phenytoin, topiramate, or valproic acid. Although the seizures were relatively well controlled, moderate‐to‐profound intellectual disability was found in all except one patient who died at 3 months. Significance De novo KCNQ2 mutations are involved in EOEE, most of which cases were diagnosed as Ohtahara syndrome. These cases showed distinct features with early neonatal onset, tonic seizures, a suppression‐burst EEG pattern, infrequent evolution to West syndrome, and good response to sodium channel blockers, but poor developmental prognosis. Genetic testing for KCNQ2 should be considered for patients with EOEE.

The

To elucidate the ligand-receptor relationship of the natriuretic peptide system, which comprises at least three endogenous ligands, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP), and three receptors, the ANP-A receptor or guanylate cyclase-A (GC-A), the ANP-B receptor or guanylate cyclase-B (GC-B), and the clearance receptor (C-receptor), we characterized the receptor preparations from human, bovine, and rat tissues and cultured cells with the aid of the binding assay, Northern blot technique, and the cGMP production method. Using these receptor preparations, we examined the binding affinities of ANP, BNP, and CNP for the C-receptor and their potencies for cGMP production via the ANP-A receptor (GC-A) and the ANP-B receptor (GC-B). These analyses revealed the presence of a marked species difference in the receptor selectivity of the natriuretic peptide family, especially among BNPs. Therefore, we investigated the receptor selectivity of the natriuretic peptide family using the homologous assay system with endogenous ligands and receptors of the same species. The rank order of binding affinity for the C-receptor was ANP greater than CNP greater than BNP in both humans and rats. The rank order of potency for cGMP production via the ANP-A receptor (GC-A) was ANP greater than or equal to BNP much greater than CNP, but that via the ANP-B receptor (GC-B) was CNP greater than ANP greater than or equal to BNP. These findings on the receptor selectivity of the natriuretic peptide family provide a new insight into the understanding of the physiological and clinical implications of the natriuretic peptide system.

Background-Rho-associated kinase (ROCK), an effector of small GTPase Rho, regulates vascular tone via a calcium sensitization mechanism and plays a key role in the pathogenesis of hypertension. However, its role in vascular growth remains unclear. Methods and Results-Y-27632, a specific ROCK inhibitor, and the overexpression of dominant-negative ROCK suppressed the mitogen-induced DNA synthesis of cultured vascular smooth muscle cells (VSMCs), which indicates the essential role of ROCK in the control of VSMC proliferation in vitro. Y-27632 also suppressed the chemotaxis of VSMCs. Male Wistar rats were systemically given Y-27632 (35 to 70 mg ⅐ kg Ϫ1 ⅐ day Ϫ1 ) through an intraperitoneal infusion. The neointimal formation of balloon-injured carotid arteries was significantly suppressed in Y-27632-treated rats (intima/media ratio, 0.22Ϯ0.02) compared with vehicle-treated rats (intima/media ratio, 0.92Ϯ0.21) or hydralazine-treated rats with a similar blood pressure decrease (intima/media ratio, 1.03Ϯ0.15). The phosphorylation of myosin phosphatase and myosin light chain was elevated in injured arteries in a Y-27632-sensitive manner, indicating the augmentation of ROCK activity in neointimal formation. The downregulation of the cyclin-dependent kinase inhibitor p27 kip1 in injured vessels was reversed by Y-27632 treatment, reflecting the antiproliferative effect of ROCK inhibition in vivo. Conclusions-We conclude that ROCK plays a key role in the process of neointimal formation after balloon injury. Thus, the inhibition of ROCK may be a potential therapeutic strategy for treating vascular proliferative disorders and hypertension. Key Words: atherosclerosis Ⅲ muscle, smooth Ⅲ remodeling Ⅲ signal transduction Ⅲ hypertension E levated vascular tone contributes to the pathogenesis of hypertension. Rho-associated kinase (ROCK), 1 a target of small GTPase Rho, regulates vascular contractility by increasing the level of phosphorylated myosin light chain and thereby elevating the calcium sensitivity of vascular smooth muscle cells (VSMCs). 2 Recently, Uehata et al 3 developed a potent, specific, ROCK inhibitor, Y-27632. The administration of Y-27632 to several hypertensive rat models markedly reduced systolic blood pressure (SBP), implicating ROCK as a key mediator in the pathogenesis of hypertension. 3 We and others have reported that regulators of vascular tone, such as angiotensin II or natriuretic peptides, are also involved in vascular growth. 4 Thus, we postulated that intracellular mechanism(s) should exist that govern both vascular contraction and growth. Using Y-27632 and dominant-negative ROCK, the present study demonstrates that ROCK, the key regulator of vascular contraction, also controls vascular growth in vitro and in vivo. Methods MaterialsY-27632 was obtained from Yoshitomi Pharmaceutical Industries, Osaka, Japan. The pCAG-myc and pCAG-myc-KD-IA plasmids 1 were a gift from T. Ishizaki and S. Narumiya (Kyoto University). The pEXV-myc-N19RhoA was from M. Symons (the Picower Institute for Medical Research), and...

Collectively, STXBP1 aberrations can account for about one-third individuals with EIEE (14 of 43). These genetic and biologic data clearly showed that haploinsufficiency of STXBP1 is the important cause for cryptogenic EIEE.

To study synthesis, storage, and secretion of brain natriuretic peptide (BNP) in the heart, we have measured BNP mRNA and BNP concentrations in the hearts of Wistar-Kyoto rats and also have investigated its secretion from the isolated perfused heart. The atrium expressed the BNP gene at a high level, and a considerable amount of BNP mRNA also was present in the ventricle, which corresponded to approximately 40%o of the atrial BNP mRNA concentration. When tissue weight was taken into account, the total content of BNP mRNA in the ventricle was approximately threefold larger than that in the atrium, although the atrial natriuretic peptide (ANP) mRNA content in the ventricle was only 7% of that in the atrium. By contrast, the BNP concentration in the ventricle was 4.07±0.97 pmol/g, which was less than 1% of that in the atrium (451±86 pmollg). The basal secretory rate of BNP from the isolated perfused whole heart was 49.3+±6.1 fmol/min, approximately 60%o of which was maintained even after atrial removal, whereas the secretory rate of ANP was reduced to less than 5%. We also studied age-matched spontaneously hypertensive rats-stroke prone. The rank order of the BNP mRNA concentration in the hearts of these rats was left ventricle>right ventricle> right atrium=left atrium, and the total BNP mRNA content and BNP secretory rate in the ventricle were twice as large as in Wistar-Kyoto rats. These results demonstrate that BNP is a novel cardiac hormone in rats and is predominantly synthesized in and secreted from the ventricle. This is in striking contrast to ANP, which occurs mainly in the atrium.