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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Maternal cardiac output, blood pressure, heart rate, fetal blood pressure, heart rate and respiratory blood gases, and uterine blood flow were measured in six pregnant monkeys during halothane-nitrous oxide and oxygen anesthesia and compared to theses same parameters observed during nitrous oxide and oxygen anesthesia. Halothane 1.5% was associated with a decrease in maternal arterial pressure (54%), heart rate (10%), cardiac output (17%), total peripheral resistance (40%), and uterine blood flow (38%). Mean fetal heart rate decreased 18% and mean fetal blood pressure 22%. These changes in fetal hemodynamics were probably related to a direct depression of the fetal cardiovascular system and its usual compensatory mechanism as well as the fetal asphyxia secondary to the decrease in uterine blood flow.
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PMID:Maternal and fetal responses to halothane in pregnant monkeys. 113 99

Halothane strikingly decreases spontaneous and electrically stimulated release of norepinephrine from the isolated guinea pig hypogastric nerve--vas deferens preparation. This depression of adrenergic discharge appears to be a direct action on the sympathetic nerve endings and may in part account for the cardiovascular depression seen during halothane administration. Although halothane depressed stimulation-induced release of norepinephrine, it did not proportionately diminish release of dopamine-beta-hydroxylase. Possible mechanisms of the dissociation between catecholamine and enzyme release are discussed.
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PMID:Inhibition by halothane of release of norepinephrine, but not of dopamine-beta-hydroxylase, from guinea-pig vas deferens. 114 93

On 10 patients who had to undergo a ca. 4 hour operation of the lower abdominal region, the pattern of catecholamine excretion before, during and after operation was traced. 1. A decrease of systolic blood pressure on average of 80 mm Hg, in correlation to the concentration of Halothane and Thalamonal, was recorded. 2. The excretion of adrenaline and noradrenalin was significantly lower during anaesthesia as compared with the initial value, suggesting a depression of sympathoadrenal system. 3. The postoperative amount of adrenaline and especially noradrenaline increased markedly, when anaesthesia worn off, postoperative shivering started, and surgical wounds caused pain. 4. The excretion of urine during operation was slightly reduced, the renal output showed normal amounts, when calculated up to 24 hours. The results show, that the combined use of halothane an thalamonal because of its depressant effects on the sympathoadrenal system is capable of reducing the liberation of catecholamines during anaesthesia.
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PMID:[The course of the catecholamine excretion during combination anaesthesia with halothane and thalamonal (author's transl)]. 121 2

The effects of Halothane, Fentanyl and droperidol in combination on the circulatory system, the preganglionic sympathetic nerve activity and the respiratory centre were examined in 21 experiments carried out on cats which were relaxed and artificially ventilated with nitrous oxide in oxygen. The results showed that even the minimal dosage of 0.5 vol-% Halothane combined with 0.0042 mg/kg Fentanyl and 0.15 mg/kg droperiodol led to a significant decrease of blood pressure and a depression of the sympathetic and phrenic nerve activity both in rest and in stress during asphyxia. A dosage of 1 vol-% Halothane produced a significant increase in the above mentioned effects when at rest, while the doubled dosage of Fentanyl and droperidol combined with the original Halothane dosage of 0.5 vol-% produced no marked increase in its effects. A comparison of these results with those of previous experiments using only the inhalation of Halothane shows that an anaesthesia consisting of 0.5 vol-% Halothane combined with Fentanyl and droperidol has virtually equal effects on the decrease of blood pressure and on the depression of central sympathetic nerve activity as the inhalation of 1 vol-% Halothane alone. Using a combination of 1 vol-% Halothane, Fentanyl and droperidol the effects induced by 2 vol-% Halothane are reached.
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PMID:[The effects of combining halothane and neuroleptanalgesia on the preganglionic sympathetic activity, the respiratory centre and the circulation (author's transl)]. 121 4

The effects of i.v. injected Fentanyl and droperidol used either singly or in combination were observed in 50 experiments carried out on cats which had been relaxed and artificially respirated. The preganglionic discharges of the cervical sympathetic nerve and action potentials of the phrenic nerve, the mean arterial pressure and the heart rate were recorded. The experiments showed that with the dosage of 0.0042-0.0083 mg/kg Fentanyl no significant change in the recorded functions took place. The dosage of 0.0166 mg/kg Fentanyl led to an activation of the central sympathetic activity and to a inhibition of the respiratory centre which persisted for as long as 60 min after the injections. Other than as above, a dosage of 0.15-0.6 mg/kg droperidol led to a decrease of the blood pressure and a depression of the sympathetic nerve activity, while the activity of the phrenic nerve remained unchanged. The effect on the blood pressure was mainly influenced by the central nervous system as the inhibition of the pressor effect of noradrenaline was only minimally. The dosage of 0.0083 mg/kg Fentanyl combined with 0.3 mg/kg dropendol as administered for neuroleptanalgesia led to a decrease in blood pressure and a depression of the central sympathetic and phrenic nerve activity both in rest and in stress during asphyxia. The effects were minimal and accorded virtually to the effects produced by 0.5 vol-% Halothane during the first 25 min of inhalation, which had been registered in previous experiments. Contrary to the effects of Halothane, neuroleptanalgesia produced no decrease in the heart rate, no depression on the pressor effects of noradrenaline and no accumulation of irregularities in cardiac rhythm after administration of noradrenaline.
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PMID:[The effects of neuroleptanalgesia on the sympathetic activity and the circulation in animals (author's transl)]. 121 5

The effect of halothane or nitrous oxide or both, on division of cultured, murine bone-marrow cells was investigated. Halothane caused a dose-dependent depression of growth rate ranging from a minimal effect at 0.5% to almost total inhibition at 2.0%. Nitrous oxide 75% had an effect similar to 0.5% halothane and the combination of 0.75% halothane with 75% nitrous oxide produced results little different from 1.0% halothane alone. There was good recovery from 1.0% but not from 2.0% halothane. It is concluded that, in vitro, bone-marrow cells show a similar sensitivity to these agents as was found for other mammalian cell lines which have been investigated. The effect of nitrous oxide was no more than proportional to its narcotic potency relative to halothane.
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PMID:Effect of inhalation anaesthetics on division of bone-marrow cells in vitro. 125 18

The effects of halothane on the effective refractory period (ERP) and the ventricular activation were examined in a canine myocardial infarction model, and compared with those of propranolol. Halothane reduced the heart rate and prolonged the ERP in both normal and infarcted zones. A prolongation of ERP with halothane was also observed during atrial pacing at the same rate as in control, but the effect was less than during sinus rhythm. Halothane (1 MAC) further delayed or blocked the delayed activation in the infarcted zones with only slight effects on the activation of the normal zones. Propranolol (0.2 mg/kg) prolonged ERP during sinus rhythm, but it did not affect either the ERP or ventricular activation during atrial pacing. In conclusion, halothane produced a selective depression of the delayed activation and the prolongation of ERP, which may be caused by both direct effects on the myocardium and secondary effects such as a reduction of the heart rate. These effects of halothane may contribute to its antiarrhythmic effects in the myocardial infarction model which have been previously reported.
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PMID:Comparison of the effects of halothane and propranolol on the effective refractory period and the ventricular activation in a canine myocardial infarction model. 128 97

We studied the effects of halothane on the electrophysiologic and biochemical properties of both Langendorff perfused hearts and single ventricular myocytes isolated from guinea pigs. Isometric contractions of left ventricles in perfused hearts, elicited by atrial pacing, decreased to 14% of control after exposure to 2% halothane-equilibrated perfusate. Subsequently the slow inward Ca2+ current (ICa) was recorded in isolated myocytes with a whole cell voltage clamp technique. ICa, recorded in response to 100-ms depolarizations from -40 mV to 0 mV, was decreased by 2% halothane to 28.4% of control. Halothane-induced ICa depression did not exhibit use dependency. To define a possible site at which halothane acts, we measured the cyclic adenosine 3',5'-monophosphate (cAMP) content of single ventricular myocytes using a radioimmunoassay. Two percent halothane decreased myocardial cAMP content to 68.9% of control. Further addition of dibutyryl cAMP (10(-3) mol/L) partially reversed the depressed contractility during 2% halothane administration in perfused hearts. In conclusion, the present study demonstrated that the decrease of myocardial cAMP by halothane was due to a direct action, at least partly, and not to other factors such as catecholamines, and suggested that the decreases in contractility and ICa were induced possibly through the decrease in cellular cAMP.
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PMID:Effects of halothane on electrophysiologic properties and cyclic adenosine 3',5'-monophosphate content in isolated guinea pig hearts. 131 11

The present study evaluates the action of volatile anesthetics on the voltage-dependent Ca2+ channels in isolated rat brain membranes, measured as changes in binding of the Ca2+ channel blocker [3H]isradipine to these membranes. Equilibrium binding studies with increasing concentrations of [3H]isradipine (0.01-1 nM) in the presence of halothane (1.9%), isoflurane (2.3%), and enflurane (4.8%) at 25 degrees C were performed. Only halothane produced a significant depression in the specific binding of isradipine to the brain membranes at 0.5 and 1.0 nM [3H]isradipine (P = 0.028 and 0.018, respectively). Isoflurane and enflurane had such inconsistent effects that the data were inconclusive. Halothane produced a significant dose-dependent inhibition of binding, the maximum inhibition being 44% (P less than 0.005). Nonlinear regression analysis fit of the binding data indicates halothane produced a 48% decrease (P less than 0.05) in the maximal number of binding sites (Bmax) with no effect on the dissociation constant (Kd). As voltage-dependent Ca2+ channels are important in mediating neurotransmission, the marked decrease in channel number (Bmax) associated with halothane exposure suggests that this phenomenon might be related to the mechanism of general anesthesia.
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PMID:Depression of calcium channel blocker binding to rat brain membranes by halothane. 131 28

Significant depression of mucociliary function occurs during general anesthesia. One possible mechanism to account for this effect is a change in ion and water transport across airway epithelium. To determine if anesthetics alter epithelial cell function, we used electrophysiologic techniques to measure the effects of halothane on ion transport of in vitro canine tracheal epithelial. Epithelial tissues were mounted in an Ussing chamber and the short-circuit current (Isc) (a measure of active ion transport) and transepithelial resistance were determined in the absence and presence of halothane. Halothane induced a rapid and reversible decrease in Isc that was dose-dependent. Four percent halothane reversibly decreased Isc from 90 +/- 11 to 39 +/- 6 microA/cm2 (n = 12; P = 0.001) and increased transepithelial resistance. Isoproterenol is a well-known activator of chloride secretion that acts via beta-adrenergic receptors and cyclic adenosine monophosphate (cAMP). Pretreatment with isoproterenol or dibutyryl cAMP (a cell permeable analogue of cAMP) increased the percent inhibition of Isc by 4% halothane. These effects are consistent with preferential inhibition of chloride secretion by halothane but rule out a primary action of halothane on the beta-adrenergic system. In the presence of indomethacin, which eliminates the contribution of chloride secretion to Isc, 4% halothane induced a much smaller but still significant inhibition. This suggests that sodium absorption is also affected. We conclude that halothane significantly decreases ion and water transport in canine epithelia and that impaired fluid secretion may contribute to decreased mucous clearance in the perioperative period.
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PMID:Halothane inhibition of ion transport of the tracheal epithelium. A possible mechanism for anesthetic-induced impairment of mucociliary clearance. 131 9


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