Maintenance of norepinephrine (NE)-induced contraction is dependent on Ca2+ influx through L-type voltage-dependent Ca2+ channels (VDCC), which is opposed by nitric oxide. Adrenergic receptors are coupled with different G proteins, including inhibitory G proteins (Gi) that can be inactivated by pertussis toxin (PTX). Our study was aimed to investigate the effects of endothelium removal, PTX pretreatment and acute VDCC blockade by nifedipine on the contractions of femoral arteries stimulated by norepinephrine. We used 12-week-old male WKY, half of the rats being injected with PTX (10 μg/kg i.v., 48 h before the experiment), which considerably reduced their blood pressure (BP). Contractions of isolated arteries were measured using Mulvany-Halpern myograph. NE dose-response curves determined in femoral arteries from PTX-treated WKY rats were shifted to the right compared to those from control WKY. On the contrary, removal of endothelium augmented NE dose-response curves shifting them to the left. Acute VDCC blockade by nifedipine (10-7 M) abolished all differences in NE dose-response curves which were dependent on the presence of either intact endothelium or functional Gi proteins because all NE dose-response curves were identical to the curve seen in vessels with intact endothelium from PTX-treated animals. We can conclude that BP reduction after PTX injection is accompanied by the attenuation of NE-induced contraction of femoral arteries irrespective of endothelium presence. Moreover, our data indicate that both vasodilator action of endothelium and Gi-dependent vasoconstrictor effect of norepinephrine operate via the control of Ca2+ influx through VDCC., S. Líšková, J. Kuneš, J. Zicha., and Obsahuje bibliografii a bibliografické odkazy
Nozokomiální nákazy (NN) představují světový problém. Původci NN jsou častěji grampozitivní koky stafylokoky na jednotkách intenzivní péče chirurgických oborů, hlavně kardiochirurgie. Stafylokoky jsou původci katetrových sepsí. Dále se uplatňují jako nozokomiální kmeny bakterie z rodu Enterobacteriaceae. U starších pacientů převládají nozokomiální kmeny Escherichia coU, Klebsiella pneumoniae, Proteus mirabilis. Většina nozokomiálních kmenů je multirezistentní, proto se komplikace způsobené nozokomiálními kmeny léčí obtížně, hlavně u starších lidí pro jejich rizikové faktory, multimorbiditu, trvalou léčbu mnoha léky vč. fyziologických i patologických změn, které ovlivňují farmakoterapii i terapii ATB. Nutné je předcházet nozokomiálním nákazám nejen u starších pacientů, kde NN představuje komplikaci klinického stavu, která i při dodržení všech zásad a opatření nemusí končit uzdravením., Nosocomial diseases (ND) represent a worldwide problem. The causal agents of ND very often are gram-positive cocci - staphylococci found at intensive care units of surgical departments, mainly of cardio surgery departments. Staphylococci are causal agents of catheter sepsis. Furthermore, members of the family enterobacteriaceae also act as nosocomial strains. The most frequent forms found in the elderly patients are nosocomial strains Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis. Most of the nosocomial strains are multiresistant, therefore complications caused by nosocomial strains are treated with difficulty. mainly in elderly patients because of many high risk factors, morbidity, permanent drug treatment including physiological and pathological changes that effect pharmacotherapy as well as ATB therapy. It is necessary to avoid nosocomial diseases not only in elderly patients, for whom ND represent complications of their clinical condition from which they do not always recover even if all rules and precautions are taken., Anna Jedličková, and Lit. 11