Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms of arterial hypotension following intravenous anesthetic induction agents are multifactorial. The purpose of this study was to evaluate and compare the effects of thiopental, propofol and etomidate on hemodynamics, sympathetic outflow and arterial baroreflex sensitivity using not only neuraxis-intact but also totally baro-denervated rabbits. A total of 60 rabbits was anesthetized with urethane, tracheotomized, and mechanically ventilated with oxygen in nitrogen (FiO2 0.5). The left renal sympathetic nerve was isolated and placed on a bipolar electrode to record renal sympathetic nerve activity (RSNA). Thirty animals underwent a surgical preparation of total baroreceptor denervation. Bolus injections of an anesthesia induction dose of thiopental 4 mg/kg and twice the induction dose of propofol 4 mg/kg significantly decreased RSNA to the same extent (19.4+/-6.7 and 19.7+/-5.2% reduction, mean +/- SEM) and mean arterial pressure (MAP) also to the same extent (19.5+/-4.6 and 22.1+/-3.1% reduction) in the neuraxis-intact animals. RSNA was increased (34.5+/-6%) without reduction of MAP by an induction dose of etomidate, 0.3 mg/kg. Sympathetic barosensitivity was attenuated even 10 min after thiopental at 4 mg/kg or propofol at 4 mg/kg (68% and 54% of control, respectively). Propofol at 2 mg/kg (induction dose) and etomidate at 0.6 mg/kg decreased RSNA and MAP only in the baro-denervated animals. It was found from the barosensitivity study that patients can be hemodynamically unstable even though blood pressure has returned to normal after thiopental and propofol administration. Data suggest that etomidate can even stimulate the sympathetic nervous system and increase sympathetic outflow. It was also clearly found from the baro-denervated animal study that thiopental was stronger than propofol in directly suppressing sympathetic outflow at the induction dose.
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PMID:Anesthetic induction agents, sympathetic nerve activity and baroreflex sensitivity: a study in rabbits comparing thiopental, propofol and etomidate. 1151 61

Propofol, an intravenous anaesthetic, has been shown to interact with the beta-subunit of the gamma-amino butyric acid(A) (GABA(A)) receptor and also to cause changes in [Ca2+]i. The GABA(A) receptor, a suggested target for anaesthetics, is known to be regulated by kinases. We have investigated if tyrosine kinase is involved in the intracellular signal system used by propofol to cause anaesthesia. We used primary cell cultured neurones from newborn rats, pre-incubated with or without a tyrosine kinase inhibitor before propofol stimulation. The effect of propofol on tyrosine phosphorylation and changes in [Ca2+]i were investigated. Propofol (3 microg mL(-1), 16.8 microM) increased intracellular calcium levels by 122 +/- 34% (mean +/- SEM) when applied to neurones in calcium free medium. This rise in [Ca2+]i was lowered by 68% when the cells were pre-incubated with the tyrosine kinase inhibitor herbimycin A before exposure to propofol (P < 0.05). Propofol caused an increase (33 +/- 10%) in tyrosine phosphorylation, with maximum at 120 s, of the beta-subunit of the GABA(A)-receptor. This tyrosine phosphorylation was decreased after pre-treatment with herbimycin A (44 +/- 7%, P < 0.05), and was not affected by the absence of exogenous calcium in the medium. Tyrosine kinase participates in the propofol signalling system by inducing the release of calcium from intracellular stores and by modulating the beta-subunit of the GABA(A)-receptor.
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PMID:A tyrosine kinase regulates propofol-induced modulation of the beta-subunit of the GABA(A) receptor and release of intracellular calcium in cortical rat neurones. 1210 Mar 62

The study was undertaken to compare measured versus calculated propofol concentrations (C(m) and C(c), respectively), by using Diprifusor technology in cardiac surgery with cardiopulmonary bypass (CPB). The study included 10 NYHA II-III patients (aged 27-45 years) undergoing mitral valve replacement. Propofol (Diprivan PFS 50 ml, AstraZeneca) was target-control infused (TCI) by the Diprifusor system (Graseby 3500). C(c) was titrated to maintain the BIS value close to 40. Propofol in doses of 2.1 +/- 0.05 mg/kg was required for induction. Anesthesia before, during, and after CPB required propofol in doses of 5.4 +/- 0.3, 3.9 +/- 0.2, and 3.1 +/- 0.2 mg/kg/h, respectively. The doses of fentanyl were 4.4 +/- 0.1 microg/kg for induction of anesthesia and 4.5 +/- 0.4, 2.4 +/- 0.2, and 0.2 +/- 0.1 mg/kg/h for its maintenance before, during, and after CPB, respectively. The patients received rocuronium in the standard doses for neuromuscular relation. C(m) was determined by high-performance liquid chromatography with ultraviolet detection (Agilent 1100, column C18, Altima). Blood propofol concentrations were measured at: 1) intubation; 2) skin incision; 3) sternotomy; 4) aortic cannulation; 5) 30 min of CPB; 6) 60 min of CPB; 7) the end of CPB; 8) 30 min following CPB; 9) skin closure; 10) awakening. Data were expressed as mean +/- SEM. The values were compared by linear regression. Student's t-test was used with p < 0.05. C(m) was 2 times higher than C(c) at all stages. A close correlation was found between C(m) and C(c): r = 0.83, p = 0.038. It is concluded that Marsh's PK/PD model predicts the trend in blood propofol concentrations during uncomplicated operations on the open heart satisfactorily, but C(c) was constantly 2 times less than C(m).
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PMID:[Calculated and measured blood propofol concentrations during target-control infusion by means of a Diprifusor system during operations under extracorporeal circulation]. 1718 57


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