Asunto(s)
Electrocardiografía , Personalidad , Adolescente , Adulto , Femenino , Humanos , Estrés PsicológicoRESUMEN
Presentation of visual and acoustic stimuli at a rate of 2-30 Hz modulated variability of the heart rhythm in volunteers. Potentation of vagal influences and a decrease in the contribution of ergotropic systems to the regulation of the heart rate were noted after 10 sessions of audiovisual stimulation. These changes were accompanied by a pronounced decrease of individual and reactive anxiety.
Asunto(s)
Estimulación Acústica , Frecuencia Cardíaca , Corazón/fisiología , Estimulación Luminosa , Adolescente , Adulto , Femenino , HumanosRESUMEN
The experiments performed in endothelin-denuded preparations (the strips of thoracic aorta and perfused tail arteries) showed that: 1) ET-1 exerts dose-dependent and slowly developing contractions and in subthreshold doses it potentiates vasoconstriction reactions to stimulate sympathetic nerve endings or phenylephrine exposure. 2) ion F(-), that activates G-proteins in the cell membranes, at a dose of 2 microM increased about two times the ET-1-induced vasoconstriction. 3) the aortic strip incubation with the protein kinase C inhibitor staurosporin led to a 50% decrease in the contraction amplitude. Results suggest that G proteins and protein kinase C may participate in the development of ET-1 induced vascular smooth muscle contraction.
Asunto(s)
Endotelinas/farmacología , Proteínas de Unión al GTP/efectos de los fármacos , Proteína Quinasa C/efectos de los fármacos , Receptores Adrenérgicos alfa/efectos de los fármacos , Vasoconstricción/efectos de los fármacos , Animales , Aorta/efectos de los fármacos , Aorta/fisiología , Endotelio Vascular/fisiología , Proteínas de Unión al GTP/fisiología , Técnicas In Vitro , Contracción Muscular/efectos de los fármacos , Contracción Muscular/fisiología , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/fisiología , Proteína Quinasa C/fisiología , Ratas , Ratas Wistar , Receptores Adrenérgicos alfa/fisiología , Vasoconstricción/fisiologíaRESUMEN
Some mechanisms responsible for extracellular Ca++ entry into rat aortic smooth muscle cells were studied in response to endothelin-1 (ET-1). Isometric tension of de-endothelialized aortic strips was recorded. It was shown that the calcium-free medium or nifedipine blockade of calcium entry diminished responses to ET-1 to 20-30% of the control levels. Depolarization of the specimens with hyperpotassium solution also reduced constriction almost by 50%. When sodium ions were replaced by NMDG in the medium, a response to ET-1 showed a 50% reduction. The findings suggest that the potential-dependent calcium channels of the L-type are involved in cellular calcium entry, the opening of the channels depending upon the entry of Na+.
Asunto(s)
Calcio/farmacología , Endotelinas/farmacología , Vasoconstricción/efectos de los fármacos , Animales , Calcio/fisiología , Canales de Calcio/efectos de los fármacos , Canales de Calcio/fisiología , Endotelio Vascular/fisiología , Técnicas In Vitro , Meglumina/farmacología , Contracción Muscular/efectos de los fármacos , Contracción Muscular/fisiología , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/fisiología , Nifedipino/farmacología , Fenilefrina/farmacología , Ratas , Ratas Wistar , Vasoconstricción/fisiologíaRESUMEN
In experiments on mice resident and stimulated thioglycolate macrophages the changes in cytoplasmic Ca2+ concentration Ca2+ have been studied by the use of the fluorescent probe fura-2. PAF acether (10(-7) M) raised Ca2+ by 300-400 nM within 1 min only in the stimulated macrophages. In the resident cells this increase was much less. In the presence of 2mM EGTA, PAF raised Ca2+ to a lesser extent. This suggests that PAF causes influx of exogenous Ca2+ through the receptor-mediated channels as well as releasing Ca2+ from intracellular stores.