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

The potency of atracurium was determined in adolescents and children during nitrous oxide-halothane and nitrous oxide-thiopentone-fentanyl anaesthesia using single dose-response curves. Dose-response curves were parallel. The effective doses producing 95% twitch depression (ED95) (mg kg-1) during nitrous oxide-halothane were larger in younger children than in the adolescents. Halothane (0.8% end-tidal) did not significantly potentiate atracurium when compared with thiopentone-fentanyl. On a microgram m-2 basis there was no difference in the ED95 between patients of different age or those anaesthetized with different techniques. At approximately 95% twitch depression intubating conditions were excellent in all groups. Minimal cardiovascular effects were noted at several multiples of the ED95.
 ...
PMID:Clinical pharmacology of atracurium in paediatric patients. 668 4

We have hypothesized that the halothane-induced depression of myocardial contractility can be explained, at least in part, by halothane's depression of adenylate cyclase, previously demonstrated in whole homogenates of myocardial tissue. Canine myocardial sarcolemmal membranes, which contain the adenylate cyclase of myocardial cells, were separated from other cellular constituents. Halothane did not depress catecholamine-stimulated adenylate cyclase activity in this preparation. Reconstitution of the sarcolemmal membrane preparation with a 100,000 X g adenylate cyclase-free supernatant restored the depressant effect of halothane on adenylate cyclase stimulated by guanosine triphosphate (GTP) 100 microM alone (-55%, P less than 0.01) or in combination with l-isoproterenol 1 microM (-38%, P less than 0.05) or 2.5 microM (-40%, P less than 0.01). Dilution of the supernatant to half-strength decreased the magnitude of the halothane-induced depression of adenylate cyclase activity to 19% (P less than 0.01); at one-quarter dilution, the effect was no longer significant. This study demonstrates the presence of endogenous modulators of the action of halothane on canine myocardial adenylate cyclase that can be reversibly separated from the adenylate cyclase complex.
 ...
PMID:Halothane inhibition of canine myocardial adenylate cyclase--modulation by endogenous factors. 670 45

Rates of cerebral glucose utilization were measured by means of the autoradiographic 2-deoxy-D-(1-14C)glucose technique in normal rats under light halothane-anesthesia. Three types of region-specific metabolic alterations were elicited by inhalation of 0.5% halothane. The most striking effect observed was a significant increase of glucose consumption within the locus coeruleus, substantia nigra compacta and reticulata, interpeduncular nucleus, hippocampus, and fornix of the anesthetized animals in comparison to the corresponding brain areas of the conscious control rats. Halothane-anesthesia was also associated with significant metabolic depression in 21 (out of the 74 examined) discrete regions of the rat brain, distributed within the pons, cerebellum, diencephalon, and cortex, and was more prevalent in thalamus and neocortex. However, halothane failed to alter consistently the rates of glucose utilization in the rest of the rat brain areas investigated. The present findings suggest that halothane specifically alters the regional cerebral glucose utilization, with some limbic system components and the basal ganglia displaying increased metabolism, in contrast to the sensorimotor system which demonstrates significantly decreased metabolic activity.
 ...
PMID:Local cerebral glucose consumption in the rat. I. Effects of halothane anesthesia. 682 87

Although halothane has been shown to depress left ventricular function, it remains a common alternative to narcotic anesthesia in cardiac operations. To clarify the mechanism by which this functional depression occurs (direct decrease in contractility versus altered diastolic compliance), we studied seven dogs in the closed-chest state following instrumentation with ultrasonic dimension transducers to measure left ventricular anteroposterior diameter and micromanometers to measure transmural left ventricular pressure. Ventricular volumes were varied with transient vena caval occlusions in the awake state and following general anesthesia with halothane at 1% and 2% end-tidal concentrations. Ventricular contractility was assessed by the slope of the end-systolic pressure-diameter relationship (EES). Following normalization of end-diastolic diameters with a Lagrangian strain definition (E), diastolic compliance was assessed by fitting end-diastolic pressure-strain data to the exponential: P = alpha (e beta E -1), where alpha and beta are nonlinear elastic coefficients. Halothane was found to produce a significant, dose-dependent decrease in EES from 10.6 +/- 0.6 control to 6.7 +/- 0.4 at 1% halothane and 4.2 +/- 0.5 at 2% halothane (p less than 0.05, control versus both 1% and 2% halothane). Furthermore, halothane at the concentrations studied did not significantly alter alpha and beta nor significantly shift the exponential end-diastolic pressure-strain curve from control. These data indicate that halothane produces a direct, severe depression of left ventricular contractility without primarily altering the diastolic mechanical properties of the myocardium.
 ...
PMID:The mechanism of halothane-induced myocardial depression. Altered diastolic mechanics versus impaired contractility. 685 54

The effects of ouabain infusion were tested in six lambs before and after depression of myocardial function by halothane anesthesia. Halothane reduced the left ventricular rate of pressure rise (dp/dt), stroke work, and stroke volume; the ratio of preejection period to left ventricular ejection time rose. Heart rate and systemic vascular resistance did not change. Before halothane, ouabain infusion did not alter the hemodynamic variables measured. After myocardial depression, ouabain infusion returned dp/dt, stroke work, stroke volume and the ratio of preejection period to left ventricular ejection time to control levels. Pacing studies showed a biphasic relationship between left ventricular dp/dt and heart rate. Maximal dp/dt occurred at a heart rate 42 beats/min higher than the resting rate. These studies suggest resting myocardial performance in the healthy, newborn lamb is at near maximal level.
 ...
PMID:The effects of ouabain in lambs with depressed myocardial function. 709 54

We evaluated the effect on diastolic myocardial compliance of halothane and morphine sulfate using 15 swine placed on total cardiopulmonary and right heart bypass with controlled aortic pressure, heart rate, and left ventricular preload. The animals were divided into three equal groups: (I) regional block anesthesia, (II) morphine sulfate (10 mg/kg), and (III) halothane anesthesia at 0.5%. Myocardial performance was evaluated on right heart bypass following a 30 minute period of total cardiopulmonary bypass before and after administration of the anesthetic agent by measuring stroke volume, left ventricular end-diastolic pressure, and left ventricular end-diastolic volume. All perfusions were at normothermia, at a hematocrit level of 30%, and at a normal arterial Po2. PCO2, and pH. Neither regional block nor morphine sulfate anesthesia significantly depressed the myocardium or changed diastolic compliance. Halothane, however, significantly decreased diastolic compliance so that stroke volume was less at a given left ventricular end-diastolic pressure, but not at a given left ventricular end-diastolic volume. The depression of stroke volume with halothane following cardiopulmonary bypass at equal filling pressures appears to be due primarily to a change in compliance rather than to a change in contractility.
 ...
PMID:Effects of halothane and morphine sulfate on myocardial compliance following total cardiopulmonary bypass. 719 84

Halothane and enflurane were compared in 131 children undergoing adenoidectomy with or without tonsillectomy. Anaesthesia for adenoidectomy was induced with thiopentone or Althesin and for tonsillectomy with thiopentone. The response to surgery was minimal (0-5%) during both inhalation anaesthetics. During immediate recovery, respiratory depression was more profound after enflurane than after halothane. Both the i.v. and the inhalation anaesthetics had an influence on recovery. The total recovery scores (0-10) based on activity, respiration, heart rate, consciousness and colour improved most rapidly after Althesin + enflurane and most slowly after thiopentone + halothane on the adenoidectomy groups. In the tonsillectomy groups, the recovery scores were better after enflurane than after halothane. After both inhalation anaesthetics, the frequency of shivering ranged from 0 to 17%.
 ...
PMID:Comparison of halothane and enflurane anaesthesia for otolaryngological surgery in children. 723 78

Isolated human taenia libera shows spontaneous motility in the organ bath. The active basal tone, force development and frequency of spontaneous contractions and total power parameter "Montevideo Units" were first analysed under control conditions. Halothane lowered the active basal tone, frequency and the total power of the muscle strip in a dose-dependent manner. The amplitude and force of contraction of human taenia libera first began to increase under halothane, attaining its maximum at 1.0 vol.%. Halothane concentrations above 1.5 vol.% at first caused a depression and finally abolished spontaneous motility. The changes in the spontaneous motility pattern brought about by halothane were completely reversible. Possible causes for the halothane effect were considered as to the possible relevance to the in vivo situation.
 ...
PMID:[Halothane and spontaneous motility of human taenia libera in vitro (author's transl)]. 728 14

Dantrolene, a skeletal muscle relaxant, has been proven prophylactic and therapeutic for malignant hyperthermia (MH) in swine. This study examined the feasibility of using a dantrolene dose response as measured by indirectly evoked foretoe twitch depression as a means to safely discriminate MH susceptibility in swine. The effect of halothane on the dantrolene response was quantified. Subjects were five Poland China malignant hyperthermia susceptible (MHS) and five Hampshire malignant hyperthermia resistant (MHR) swine. Dantrolene dose response was determined twice in each anaesthetized subject, once with thiopentone and subsequently with thiopentone and halothane. Dantrolene in incremental doses, 0.15 mg.kg-1, was given to a cumulative dose of 2--3 mg.kg-1. Under thiopentone anaesthesia, the dantrolene dose responses were similar in MHS and MHR animals. The presence of halothane augmented dantrolene twitch depression in MHS but not MHR animals when compared to their response under thiopentone. Under halothane, the MHS animals had significantly augmented dantrolene response compared to MHR pigs, but three MHS animals had developed the MH syndrome prior to receiving dantrolene. We conclude that dantrolene muscle relaxant dose response cannot be used as a diagnostic test for MHS in swine. Halothane augments dantrolene twitch depression in MHS swine.
 ...
PMID:Porcine malignant hyperthermia--failure of dantrolene dose response to diagnose susceptibility (halothane effect). 735 86

Heart muscle is dependent on the entry of calcium from the extracellular fluid to support contraction, and neonatal hearts are particularly sensitive to reductions in transsarcolemmal entry of calcium. Accordingly, this study evaluated the ability of the calcium channel agonist BAY K8644 to prevent or reverse the myocardial depressant effects of halothane or isoflurane in right ventricular papillary muscles from neonatal rabbits. The ability of BAY K8644 to reverse reductions in force (F) and dF/dt (halothane and isoflurane) or prevent reduction (halothane) was studied. Halothane decreased F to 24 +/- 2% of baseline values (p = 0.001). The addition of BAY K8644 reversed F to only 54 +/- 3% of baseline (p = 0.001 vs. baseline and p = 0.002 vs. halothane alone). Isoflurane decreased F to 20 +/- 2% of baseline (p = 0.001) with a return to 45 +/- 4% of baseline with the addition of BAY K8644 (p = 0.0001 vs. baseline and p = 0.0025 vs. isoflurane alone). With BAY K8644 in the bath prior to the addition of halothane, halothane decreased F to 38 +/- 4% of baseline (p = 0.001). dF/dt mirrored changes in F in all studies. These data show that a calcium channel agonist is only partially effective in modulating volatile anesthetic-induced depression in neonatal rabbit ventricular papillary muscle.
 ...
PMID:Effect of calcium channel agonist (BAY K8644) on volatile anesthetic-mediated depression in neonatal rabbit papillary muscle. 752 47


<< Previous 1 2 3 4 5 6 7 8 9 10