RESUMEN
The bradykinin-potentiating peptides from Bothrops jararaca venom are the most potent natural inhibitors of the angiotensin-converting enzyme. The biochemical and biological features of these peptides were crucial to demonstrate the pivotal role of the angiotensin-converting enzyme in blood pressure regulation. In the present study, seven bradykinin-potentiating peptides were identified within the C-type natriuretic peptide precursor cloned from snake brain. The bradykinin-potentiating peptides deduced from the B. jararaca brain precursor are strong in vitro inhibitors of the angiotensin-converting enzyme (nanomolar range), and also potentiate the bradykinin effects in ex vivo and in vivo experiments. Two of these peptides are novel bradykinin-potentiating peptides, one of which displays high specificity toward the N-domain active site of the somatic angiotensin-converting enzyme. In situ hybridization studies revealed the presence of the bradykinin-potentiating peptides precursor mRNAs in distinct regions of the B. jararaca brain, such as the ventromedial hypothalamus, the paraventricular nuclei, the paraventricular organ, and the subcommissural organ. The biochemical and pharmacological properties of the brain bradykinin-potentiating peptides, their presence within the neuroendocrine regulator C-type natriuretic peptide precursor, and their expression in regions of the snake brain correlated to neuroendocrine functions, strongly suggest that these peptides belong to a novel class of endogenous vasoactive peptides.
Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Encéfalo/metabolismo , Péptido Natriurético Tipo-C , Oligopéptidos/farmacología , Fragmentos de Péptidos/farmacología , Precursores de Proteínas/genética , Secuencia de Aminoácidos , Inhibidores de la Enzima Convertidora de Angiotensina/química , Animales , Bioensayo , Presión Sanguínea/efectos de los fármacos , Bothrops , Bradiquinina/farmacología , Química Encefálica , Sinergismo Farmacológico , Cobayas , Íleon/efectos de los fármacos , Técnicas In Vitro , Masculino , Datos de Secuencia Molecular , Contracción Muscular/efectos de los fármacos , Péptido Natriurético Tipo-C/biosíntesis , Oligopéptidos/química , Oligopéptidos/genética , Especificidad de Órganos , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Precursores de Proteínas/química , Precursores de Proteínas/metabolismo , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Especificidad por SustratoRESUMEN
The bradykinin-potentiating peptides from Bothrops jararaca venom are the most potent natural inhibitors of the angiotensin-converting enzyme. The biochemical and biological features of these peptides were crucial to demonstrate the pivotal role of the angiotensin-converting enzyme in blood pressure regulation. In the present study, seven bradykinin-potentiating peptides were identified within the C-type natriuretic peptide precursor cloned from snake brain. The bradykinin-potentiating peptides deduced from the B. jararaca brain precursor are strong in vitro inhibitors of the angiotensin-converting enzyme (nanomolar range), and also potentiate the bradykinin effects in ex vivo and in vivo experiments. Two of these peptides are novel bradykinin-potentiating peptides, one of which displays high specificity toward the N-domain active site of the somatic angiotensin-converting enzyme. In situ hybridization studies revealed the presence of the bradykinin-potentiating peptides precursor mRNAs in distinct regions of the B. jararaca brain, such as the ventromedial hypothalamus, the paraventricular nuclei, the paraventricular organ, and the subcommissural organ. The biochemical and pharmacological properties of the brain bradykinin-potentiating peptides, their presence within the neuroendocrine regulator C-type natriuretic peptide precursor, and their expression in regions of the snake brain correlated to neuroendocrine functions, strongly suggest that these peptides belong to a novel class of endogenous vasoactive peptides.