Nitric oxide (NO) plays a crucial role not only in regulation of blood pressure but also in maintenance of cardiac autonomic tone and its deficiency induced hypertension is accompanied by cardiac autonomic dysfunction. However, underlying mechanisms are not clearly defined. We hypothesized that sympathetic activation mediates hemodynamic and cardiac autonomic changes consequent to deficient NO synthesis. We used chemical sympathectomy by 6-hydroxydopamine to examine the influence of sympathetic innervation on baroreflex sensitivity (BRS) and heart rate variability (HRV) of chronic NG-nitro-L-arginine methyl ester (L-NAME) treated adult Wistar rats. BRS was determined from heart rate responses to changes in systolic arterial pressure achieved by intravenous administration of phenylephrine and sodium nitroprusside. Time and frequency domain measures of HRV were calculated from 5-min electrocardiogram recordings. Chronic L-NAME administration (50 mg/kg per day for 7 days orally through gavage) in control rats produced significant elevation of blood pressure, tachycardia, attenuation of BRS for bradycardia and tachycardia reflex and fall in time as well as frequency domain parameters of HRV. Sympathectomy completely abolished the pressor as well as tachycardic effect of chronic L-NAME. In addition, BRS and HRV improved after removal of sympathetic influence in chronic L-NAME treated rats. These results support the concept that an exaggerated sympathetic activity is the principal mechanism of chronic L-NAME hypertension and associated autonomic dysfunction., M. Chaswal, S. Das, J. Prasad, A. Katyal, M. Fahim., and Obsahuje bibliografii
Ačkoliv texty mnohých populárních písní nejsou žádné básnické skvosty, mnohý slogan v nich obsažený se nám vryje do paměti, aniž bychom si to příliš přáli. Takže asi většina z nás si vybaví fragment textu, který tvrdí, že "...Brno je zlatá loď, za děvčaty z Brna choď..." Pokud text popisuje reálnou situaci, pak je prapoddivné, že brněnští astronomové si místních dívek vůbec nehledí, ale zajímají se o jakési velmi vzdálené a údajně velmi zmalované krásky. Vedoucí skupiny astrofyziků na Přírodovědecké fakultě Masarykovy univerzity, doc. RNDr. Zdeněk Mikulášek, CSc., totiž ve svých přednáškách velmi často nazývá hvězdy svého zájmu "zmalovanými slečnami". Zda k tomu má nějaký důvod, posuďte sami - vítejte ve světě CP hvězd!, Tomáš Gráf, Zdeněk Mikulášek, Pavel Zvěřina, Jiří Krtička., and Obsahuje bibliografii
Three new species of chigger mites, Eutrombicula costaricensis sp. n., Eutrombicula passerinorum sp. n., and Eutrombicula hectochaeta sp. n. are described from wild birds from Costa Rica. Two species, Eutrombicula pacae (Floch et Fauran, 1957) and Parasecia fundata (Brennan, 1969), are recorded for the first time in Costa Rica and on new host species. Data on the distribution of Blankaartia sinnamaryi (Floch et Fauran, 1956) in Costa Rica are also reported.