Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The clinical applications of calcium channel blockers are rapidly growing; as barbiturates interfere with intracellular calcium movements, the possibility of drug interaction at this level must be considered. We have studied the haemodynamic interaction of Thiopentone and Diltiazem in pigs. A loading dose of Diltiazem (0.15 mg X kg-1) was injected followed by a continuous administration of 0.07 mg X kg-1 X hour. From the fifth to the tenth minute, the reduced afterload was associated with a moderate depression of the contractility of the left ventricle. These values returned to the initial level within 30 minutes. Heart rate and cardiac output were not modified. The stability of these two parameters is thought to result from the complex interaction of both drugs on the sympathetic nervous system and the ventricular function.
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PMID:[Hemodynamic interferences between diltiazem and thiopental--experimental study in the pig]. 670 81

The changes in laryngeal resistance (LR) during respiratory arrest produced by withdrawal of hypoxia stimulation and administration of various respiratory depressants were studied in 14 spontaneously breathing, anesthetized cats (11 cats with alpha-chloralose and three cats with halothane). Withdrawal of hypoxia stimulation caused a transient respiratory arrest with no central inspiratory activity, during which a considerable increase in LR was observed to a level higher than the fixed resistance after muscle paralysis [LR(fix)]. Intravenous injection of thiopentone, ketamine, and lidocaine all caused a transient respiratory arrest. However, the effects on the laryngeal function and the central inspiratory activity were different for each agent. Both thiopentone and ketamine induced an inspiratory apneusis pattern in phrenic nerve discharge, and lidocaine caused a silence of phrenic nerve activity. Thiopentone relaxed the larynx, and LR during thiopentone-induced respiratory arrest was almost equal to LR(fix). Ketamine maintained a dilatation of the larynx, and LR during ketamine-induced respiratory arrest was lower than LR(fix). Lidocaine caused a constriction of the larynx and LR greatly increased, leading frequently to laryngospasm. These results indicate that hypoxia withdrawal, thiopentone, ketamine, and lidocaine all cause different effects on the central inspiratory activity, and that the central respiratory depression produced by these methods is not accompanied by a uniform depression of laryngeal function.
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PMID:Different laryngeal responses during respiratory arrest produced by hypoxia withdrawal, thiopentone, ketamine, and lidocaine in cats. 706 36

The effects of thiopentone and propofol on delayed hypersensitivity reactions and T lymphocyte proliferation were studied in nine healthy volunteers (five women and four men). Thiopentone 5 mg.kg-1 and propofol 2.5 mg kg-1 were given as a 10 min infusion on two separate occasions. The volunteers were exposed to a skin multitest antigen before and after administration of the two agents and their skin reactions assessed. T lymphocyte responses were studied using phytohaemagglutinin (PHA)-induced proliferation. Results showed that both drugs caused a significant depression of skin reactions in vivo but no depression in the T lymphocyte proliferation.
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PMID:The effects of thiopentone and propofol on delayed hypersensitivity reactions. 761 60

Initial resistance of bacterial infection is mediated primarily by polymorphonuclear leucocytes (PMN). Anaesthetic agents have been reported to impair various aspects of PMN function. It is possible that the use of these agents to sedate critically ill patients may further compromise an already depressed host defence mechanism. A flow cytometric technique with fresh whole blood from 10 healthy volunteers was used. Phagocytic and respiratory burst activity of PMN incubated for 1 h with either propofol, thiopentone, midazolam or ketamine at both clinical plasma concentrations and 100 times this concentration were determined. Thiopentone at the higher concentration reduced both respiratory burst activity (mean peak channel 50.7 compared with control value of 77.6 (P < 0.0001)) and phagocytosis (mean peak channel 47.5 compared with 79.9 (P < 0.0001)). Ketamine at 100 times the clinical plasma concentration also reduced respiratory burst and phagocytosis, but this failed to reach statistical significance (P = 0.10 and P = 0.053, respectively). No significant depression occurred in the other groups. The results suggest that these i.v. anaesthetic agents, at clinically relevant concentrations, have minimal effects on PMN phagocytosis and oxygen free radical production. At higher concentrations thiopentone and ketamine may affect phagocytic function and thiopentone may impair intracellular cytolysis.
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PMID:Comparison of the effects of four i.v. anaesthetic agents on polymorphonuclear leucocyte function. 771 79

In 1994, thiopentone has been in clinical use as an induction agent for 60 years. For this reason, a literature review is given dealing with its chemical properties and pharmacokinetics with special regard to plasma protein binding, recommended speed of injection, diaplacentar transfer to the foetus in Caesarean section and the transfer to breast milk. The pharmacodynamics of thiopentone are reviewed with emphasis on the effects on the CNS, the cardiovascular system, the respiratory system, renal function, liver and the effect in porphyria. Its side effects such as local reactions and release of histamine are also reviewed. The clinical importance of thiopentone in anaesthesia induction and the present state of cerebral protection are discussed, as well as the results of controlled trials comparing thiopentone to other induction drugs. Thiopentone has the main disadvantage of a slow elimination resulting in minor CNS depression, which seems of very limited clinical importance. In most respects thiopentone seems to be comparable to its younger competitors.
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PMID:[60 years thiopental]. 781 65

We have examined the effects of propofol and thiopentone on membrane potentials and currents of isolated guineapig ventricular myocytes using the whole-cell patch-clamp technique. After current clamping, propofol at concentrations greater than 0.5 mumol litre-1 shortened the plateau and action potential duration (APD) (P < 0.05). Thiopentone 10 mumol litre-1 prolonged APD (P < 0.05), whereas concentrations of 50 mumol litre-1 or higher decreased plateau height (P < 0.05) and resting membrane potential (RMP) (P < 0.05) with abbreviation of the prolonged APD. With voltage clamping, propofol 1 mumol litre-1 decreased the L-type Ca2+ current (ICa,L) to 88.4% of control (P < 0.01) without affecting the delayed rectifier K+ current (IK) and propofol 10 mumol litre-1 decreased ICa,L and IK to 75.0% (P < 0.01) and 78.4% (P < 0.01), respectively, with no effect on the inward rectifier K+ current (IK1). Thiopentone 10 mumol litre-1 decreased ICa,L to 88.5% (P < 0.01) and IK to 78.3% (P < 0.05), while thiopentone 100 mumol litre-1 depressed ICa,L to 82.8% (P < 0.01), IK to 27.0% (P < 0.01) and IK1 to 67.3% (P < 0.05). These results indicated that propofol, at concentrations greater than those that are clinically relevant, shortened APD mainly by suppression of ICa,L, and the biphasic effects on APD by thiopentone were caused by depression of IK, and concomitant suppression of ICa,L and IK1 at higher concentrations. The distinct cardiodepressant effects of propofol and thiopentone may be, at least in part, attributed to different actions on membrane Ca2+ and K+ currents.
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PMID:Comparative actions of propofol and thiopentone on cell membranes of isolated guineapig ventricular myocytes. 894 38

Electrophysiological studies with some chiral barbiturates have shown that one enantiomer can be excitant while the other is depressant. Thiopentone, a chiral barbiturate, has both differences in potency between enantiomers and biphasic effects on the electroencephalogram (EEG). This study investigated whether a differential EEG activity between the enantiomers of thiopentone could account for the biphasic effects. Rats were administered rac-, R- or S-thiopentone to determine the nature and time course of quantitative EEG effects. Two studies using computer-controlled i.v. infusions of the three drugs were performed in groups of animals previously prepared with EEG electrodes and/or arterial blood sampling cannulae. Study 1 used several stepwise increments in plasma drug concentration over 35 min, followed by washout. Study 2 used a 4 min period of constant plasma drug concentration, followed by washout. In both studies, both enantiomers and racemate caused an initial EEG activation followed by deactivation. Quantitative enantioselectivity was found for depression. The extent of depression was significantly less for R-thiopentone (P=0.008) and racthiopentone (P=0.038) than for S-thiopentone; recovery from depression appeared to be faster for R-thiopentone than either rac- or S-thiopentone. Fatality was only found with S-thiopentone (3/7 animals in Study 2). R-thiopentone plasma concentrations were approximately 8% less than those of S-thiopentone in rats treated with racthiopentone. Although small differences in clearance between enantiomers were found that may influence recovery, they were not large enough to account for the reported differences in potency between the two enantiomers.
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PMID:Electroencephalographic effects of thiopentone and its enantiomers in the rat. 1066 6

Aged persons appear to fear eye operations. Hence both patient and surgeon are more at ease with the use of a general anesthetic, particularly if the anesthetist has visited the patient before the operation and reassured him. Early ambulation, ordinarily so desirable in the aged, is curtailed in most eye operations because the head and eyes must be completely quiet. Since barbiturates are not well tolerated by aged patients, Dramamine is used instead preoperatively. Dramamine adequately sedates but does not cause depression or hallucinations. Morphine is contraindicated because of its pupillary action; Demerol is the drug of choice for preoperative medication. Xylocaine applied directly to the pyriform fossa and vocal cords prevents laryngospasm, coughing and straining. Then, following induction with Pentothal, a Guedel airway is introduced into the oropharynx and through it a continuous flow of oxygen is maintained throughout the procedure. Relaxation of the eyelids is aided by the use of various muscle relaxants, succinylcholine being the relaxant of choice because it is rapidly eliminated. By administering narcotics intravenously during the course of the operation the amount of Pentothal needed can be held to a minimum. To prevent any slowing of the respiration, Nalline is administered in conjunction with the narcotic. In dealing with debilitated patients, Nalline is usually given in conjunction with the preoperative narcotic. Any latent slowing of the respiration can be promptly relieved by an additional dose of Nalline.
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PMID:Anesthesia for eye operations in the aged. 1323 Sep 13


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