RESUMO
The regional hemodynamic effects of candesartan cilexetil (TCV-116), a selective angiotensin II AT1-receptor antagonist, and enalapril, an angiotensin-converting enzyme inhibitor, were compared in conscious spontaneously hypertensive rats (SHR). A 7-day repeated administration study was carried out. TCV-116 (1 mg/kg, p.o.) and enalapril (10 mg/kg, p.o.) reduced blood pressure to the same extent 5 hr after administration on the 1st and the 7th day. At these points, the cardiac index and organ or tissue blood flow were measured by the non-radioactive colored dye-extraction microsphere technique. Repeated administration of TCV-116, and single and repeated administration of enalapril significantly increased renal blood flow without any changes in the cardiac index. TCV-116 and enalapril also tended to increase splanchnic blood flow following the 1st dose but not the 7th dose. No significant changes in blood flow were observed in the brain, heart, adrenal, skin and skeletal muscle. These results suggest that the antihypertensive effects of TCV-116 and enalapril are attributable to the systemic reduction of vascular resistance caused by the dilatation of blood vessels. These hemodynamic effects of TCV-116, like those of enalapril, may be beneficial in the treatment of hypertension.
Assuntos
Antagonistas de Receptores de Angiotensina , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Anti-Hipertensivos/farmacologia , Benzimidazóis/farmacologia , Compostos de Bifenilo/farmacologia , Enalapril/farmacologia , Hemodinâmica/efeitos dos fármacos , Tetrazóis , Administração Oral , Glândulas Suprarrenais/irrigação sanguínea , Glândulas Suprarrenais/efeitos dos fármacos , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Animais , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/uso terapêutico , Benzimidazóis/administração & dosagem , Benzimidazóis/uso terapêutico , Compostos de Bifenilo/administração & dosagem , Compostos de Bifenilo/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Encéfalo/irrigação sanguínea , Encéfalo/efeitos dos fármacos , Circulação Coronária/efeitos dos fármacos , Modelos Animais de Doenças , Enalapril/administração & dosagem , Enalapril/uso terapêutico , Hipertensão/tratamento farmacológico , Masculino , Microesferas , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/efeitos dos fármacos , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Fluxo Sanguíneo Regional/efeitos dos fármacos , Circulação Renal/efeitos dos fármacos , Pele/irrigação sanguínea , Pele/efeitos dos fármacos , Nervos Esplâncnicos/irrigação sanguínea , Nervos Esplâncnicos/efeitos dos fármacos , Resistência Vascular/efeitos dos fármacosRESUMO
We studied sympathetic cardiovascular control in a patient after sympathectomies and found severe hypoadrenergic orthostatic hypotension before and after, but not during upright exercise. This report is the first to correlate in man anatomical sympathetic lesions with autonomic function test results and to document that in a sequence of sympathectomies orthostatic hypotension does not develop until the major part of splanchnic sympathetic outflow is destroyed.