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)

Barbiturates are often described as non-analgesic or even hyperalgesic agents; the newer intravenous anesthetic agent propofol is said to be non-analgesic. Both propofol and barbiturates occupy sites on the GABAA receptor. The present study was designed to compare the effects of propofol and barbiturates on nociceptive-related neurotransmission in neonatal rat spinal cord; to search for actions that might be hyperalgesic; and to determine the extent to which propofol depression of nociceptive neurotransmission is mediated by GABAA receptors. The monosynaptic reflex, a slow ventral root potential (slow VRP) and the dorsal root potential (DRP) were recorded from isolated neonatal (1-5 days old) superfused rat spinal cords in response to electrical stimulation of a lumbar dorsal root. The slow VRP and the DRP are related to nociception. Propofol (0.5-10 microM), pentobarbital (1-10 microM), and thiopental (1-10 microM) reversibly depressed the slow VRP. Dose-response curves were monophasic and linear over this range. The monosynaptic reflex was unaffected. The GABAA agonist muscimol (0.2-1 microM) also depressed the slow VRP. Propofol and barbiturate slow VRP depression was antagonized by the GABAA antagonist bicuculline (1 microM). Propofol depressed the response evoked by direct application of substance P. The DRP is a GABAA-mediated depolarization of primary afferent nerve terminals that diminishes the effectiveness of nociceptive input. Propofol and thiopental increased electrically evoked DRP amplitude and increased the DRP evoked by application of muscimol. Both propofol and barbiturates thus depressed the nociceptive-related slow VRP and enhanced the antinociceptive DRP; their effective concentrations are at or close to the general anesthetic range for these agents. No anti-analgesic or hyperalgesic effect was observed. (ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Propofol and barbiturate depression of spinal nociceptive neurotransmission. 146 57

We estimated the potency of vecuronium and measured the onset and duration of its action during total intravenous anesthesia with propofol to examine the possibility of any interaction between these two drugs. Propofol infusion was administered according to a three-step dosage scheme, and neuromuscular block was monitored by measuring the force of contraction of the adductor pollicis muscle after single-twitch stimulation of the ulnar nerve at 0.1 Hz. A control group of patients were similarly studied during anesthesia with thiopental, nitrous oxide, oxygen, and fentanyl. The ED50 and ED95 (dose required to produce a 50% and 95% depression of twitch tension, respectively) of vecuronium in patients given total intravenous anesthesia (n = 24) were 24 (22-27, 95% confidence limits) and 41 (37-48, 95% confidence limits) micrograms/kg, respectively, and in the control group (n = 24), 20 (17-24) and 39 (34-37) micrograms/kg, respectively. The onset of action of an 80-micrograms/kg dose (2 x ED95) of vecuronium was 3.6 +/- 1.2 and 4.1 +/- 1.7 min (mean +/- SD), in the propofol (n = 10) and control (n = 10) groups, respectively. The respective times to recovery of the twitch height to 25% of control and the recovery indices (25%-75% recovery of twitch height) in the propofol versus control groups were 28.3 +/- 6.6 and 28.0 +/- 1.7 min and 13.3 +/- 6.8 and 15.4 +/- 11.9 min, respectively. There were no significant differences in any of the measured variables between the propofol and control groups, indicating the lack of any interaction between propofol and vecuronium.
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PMID:Lack of interaction between propofol and vecuronium. 135 19

Twenty women for elective caesarean section received either propofol 2.3 mg/kgr or thiopental 4.4 mg/kgr for induction of general anaesthesia. Maintainance was similar for both groups. Mean arterial pressure and heart rate were recorded non-invasively before anaesthesia, during intubation, one and five minutes after intubation. There were no significant differences in haemodynamic response between the two groups. During intubation heart rate rose in both groups, but remained increased five minutes after tracheal intubation only in the thiopental treated women (p less than 0.05). There was no significant neonatal depression as assessed by Apgar Scores and blood gas analyses. Propofol appears to be a suitable alternative to thiopental as an induction agent for obstetric anaesthesia.
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PMID:A comparative study of propofol and thiopental as induction agents for elective caesarean section. 144 99

Administering intravenous sedation in conjunction with intraoperative monitoring to cataract surgery patients is a widely accepted technique. Numerous articles report local sedation techniques for cataract surgery that are, in essence, abbreviated general anesthetic techniques for insertion of the retrobulbar block (RBB). Because of variations in levels of consciousness, a number of complications have been encountered with this specific patient population, ie, movement upon insertion of the RBB, intraoperative patient movement, confusion, hypotension, respiratory depression, and respiratory arrest. In an attempt to meet the specific needs of this patient population, a study comparing propofol-fentanyl with midazolam-fentanyl was initiated. Seventy-five (ASA 1 to 3) patients were randomly assigned to two groups: propofol-fentanyl (P/F) or midazolam-fentanyl (M/F). The mean age of patients in the P/F group was 71.1 +/- 13 SD, and the mean age in the M/F group was 74.4 +/- 8.8 SD. All patients entered the operating room unpremedicated. Before the RBB, patients in both groups were given a single intravenous dose of 50 micrograms fentanyl. Propofol (mean dose, 24.7 mg) or midazolam (mean dose, 1.58 mg) was then titrated to slurred speech or nystagmus. Patients' responses to the RBB were evaluated and recorded by an objective observer. The amnestic properties of both agents were evaluated by patient questioning at 10 minutes and 24 hours. Levels of discomfort were evaluated on a scale of 1 to 5, with 1 being extremely uncomfortable and 5 being noticeable without pain. Respiratory depressant effects of both techniques was assessed via continuous pulse oximetry. Results were analyzed using the chi 2 test, rank t test, and SD.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Propofol-fentanyl versus midazolam-fentanyl: a comparative study of local sedation techniques for cataract surgery. 147 88

The purpose of the study was to compare the actions of propofol and thiopental on myocardial contractility and cellular electrophysiologic behavior. Isometric tension of isolated guinea pig right ventricular papillary muscle was studied in normal and 26 mM potassium Tyrode's solutions at various stimulation rates (after rest up to 3 Hz). Normal and slow action potentials were also recorded by conventional microelectrodes. Propofol (30, 100, and 300 microM) applied in the commercial 10% Intralipid emulsion caused dose-dependent depression of contractions at all stimulation rates, whereas Intralipid alone had no effect. Thiopental (10, 30, and 100 microM) caused depression similar to the threefold greater concentrations of propofol. Although neither drug altered the normal action potential (AP) amplitude or dV/dt max, thiopental (30 microM) increased AP duration. In the partially depolarized (26 mM potassium) beta-adrenergically stimulated myocardium, propofol and thiopental caused dose-dependent contractile depression similar to that in normal Tyrode's solution. Whereas propofol did not alter slow AP characteristics, 30-100 microM thiopental increased slow AP duration (consistent with decreased potassium conductance), and 100 microM thiopental depressed dV/dt max (consistent with decreased calcium channel ionic influx). Comparing the clinical plasma concentration ranges required for an equivalent anesthetic effect, propofol depresses myocardial contractility less than thiopental.
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PMID:Propofol and thiopental depression of myocardial contractility. A comparative study of mechanical and electrophysiologic effects in isolated guinea pig ventricular muscle. 153 21

Propofol is a short-acting intravenous induction agent that induces cardiovascular depression. However, the effects of propofol on intrinsic myocardial contractility remain debatable. Thus, we studied the effects of three concentrations of propofol (1, 3, and 10 micrograms.ml-1, respectively) and its solvent on the mechanics and energetics of isolated rat left ventricular papillary muscles. Propofol and its solvent did not induce any significant inotropic effect as shown by the lack of significant changes in maximum unloaded shortening velocity and in active isometric force. Nevertheless, propofol induced a slight decrease in isometric force (92 +/- 6%, 95 +/- 5%, and 95 +/- 4%, respectively, all P less than 0.01) under certain experimental conditions (i.e., after isometric stabilization). Using various afterloaded twitches, the peak power output and the curvature of the force-velocity curve were calculated. Propofol and its solvent did not significantly modify these two energetic parameters, indicating that it did not change myothermal economy and cross-bridge kinetics. Propofol impaired isotonic relaxation, suggesting that it decreased calcium uptake by the sarcoplasmic reticulum, whereas its solvent alone did not. However, alteration of sarcoplasmic reticulum function was moderate, since postrest potentiation and postrest recovery were unmodified after propofol. It was concluded that propofol induces moderate changes on intrinsic myocardial contractility. These results suggest that cardiovascular depression observed with propofol in vivo is not related to intrinsic myocardial depression.
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PMID:In vitro effects of propofol on rat myocardium. 155 Feb 86

2,6-Diisopropylphenol, a general anesthetic, was previously reported to reduce the transmembrane electrical potential in isolated rat liver mitochondria without affecting the rate of ATP production. This effect appeared to contrast with the generally accepted chemiosmotic mechanism for oxidative phosphorylation. In this study we further examined the influence of 2,6-diisopropylphenol on the production of ATP by isolated mitochondria and we studied its effect on the permeability of the inner mitochondrial membrane to protons. In order to clarify the effects of 2,6-diisopropylphenol on mitochondrial ATP production the activities of the adenine nucleotide translocator and the ATP synthetase were evaluated. The results obtained indicate that the depression of the transmembrane electrical potential elicited by 2,6-diisopropylphenol decreased the activity of the ATP synthetase (as expected in the chemiosmotic model for energy coupling), but not that of the adenine nucleotide translocator. The decrease of the ATP synthetase activity, however, did not result in an apparent inhibition of the overall rate of ATP production in isolated mitochondria due to the rate-limiting effect of the adenine nucleotide translocator in this process. Moreover 2,6-diisopropylphenol was found to increase the permeability to protons of the inner mitochondrial membrane; this effect became more marked as the pH of the incubation medium was increased, demonstrating that it involved the dissociated form of 2,6-diisopropylphenol. These observations suggested that 2,6-diisopropylphenol affected oxidative phosphorylation by acting as a mild protonophore and that its effectiveness was limited by the low fraction of phenol dissociated at near-physiological pH.
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PMID:Uncoupling effect of the general anesthetic 2,6-diisopropylphenol in isolated rat liver mitochondria. 165 82

Administration of propofol in paediatric anaesthesia is relatively recent. Cardiovascular effects are minimal. Respiratory depression observed is in part in relation with the decrease of CO2 response. EEG tracing does not show spikes or "burst suppression" for usual doses. Pharmacokinetics are similar to those reported for young adults with the exception of a larger central compartment volume. Dosage depends particularly on age, injection speed and premedication. Propofol is often used for induction, halogenated agents taking over with a narcotic and a myorelaxant. Main disadvantages is pain on injection which are reduced by addition of lignocaine. Spontaneous movements during induction appeared chiefly with low doses. The most important advantage of propofol is the rapidity and the quality of recovery. Propofol has its place in paediatric anaesthesia and in addition sedation in intensive care unit is an new unexplored field.
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PMID:[Propofol in pediatric anesthesia]. 177 70

To establish anesthesia with minimal respiratory and cardiovascular depression using propofol, the effects of varying the rate of delivery on anesthetic induction dose requirements and hemodynamic changes were studied in four groups of 20 patients each undergoing body surface surgery. All patients were premedicated with temazepam and received 1.5 micrograms/kg fentanyl 5 min before induction. Propofol was delivered at 50, 100, or 200 mg/min by the Ohmeda 9000 infusion pump (groups 1, 2, and 3, respectively) or by bolus of 2 mg/kg (group 4) until loss of verbal contact. Anesthesia was maintained thereafter with propofol infused at 6 mg.kg-1.h-1. Using slower infusion rates, induction took significantly longer (124, 92, 62, and 32 s in groups 1, 2, 3, and 4, respectively) and was achieved with significantly smaller doses of propofol (1.40, 1.96, 2.61, and 2.15 mg/kg in groups 1, 2, 3, and 4, respectively). Slow infusion (groups 1 and 2) caused less depression of systolic and diastolic blood pressure than rapid infusion (groups 3 and 4), but the differences were not statistically significant. Patients in groups 3 and 4 had significantly greater decreases in pulse rate and a greater incidence of apnea than did patients in group 1. There was no correlation between the size of the induction dose and subsequent maintenance requirements of propofol. The finding that the sleep dose of propofol is reduced at slower infusion rates has important practical and theoretical implications when considering the relative potencies of intravenous anesthetics.
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PMID:Rate-dependent induction phenomena with propofol: implications for the relative potency of intravenous anesthetics. 173 65

We have investigated the effects of propofol anaesthesia on the metabolic activity pattern of 35 regions of the rat brain and cervical spinal cord using the 14C-2-deoxyglucose technique. Anaesthesia was produced by an i.v. bolus of the commercial preparation of the drug (8 mg kg-1) and maintained with successive bolus administrations of 6 mg kg-1. Functional activity values (expressed as rates of local utilization of glucose) were reduced in 31 grey matter and two white matter structures in a propofol group relative both to saline-injected and vehicle-injected (aqueous emulsion containing 10% soya bean oil, 1.2% egg phosphatide and 2.25% glycerol) controls. Values from the two control groups did not differ significantly. Propofol-induced depression of metabolic activity was present in central nervous system regions belonging to sensory (auditory, visual and somatosensory), motor and limbic systems, including spinal cord grey matter. Mean percentage decreases ranged from 40% (vestibular nuclei) to 76% (cingulate cortex). Although these values may be slightly overestimated because of the modest increase in PaCo2 in the anaesthetized group, propofol appeared to elicit generalized reduction of central nervous system functional activity.
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PMID:Brain and spinal cord metabolic activity during propofol anaesthesia. 202 77


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