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)

Urethane (1.25 g/kg) and pentobarbital (0.06 g/kg) 30 min after i.v. application increase the content of acetylcholine in telencephalic areas but not in the brain stem. These acetylcholine levels are normalized again 120 min p.i.; but urethane treated animals show an elevated acetylcholine content in the brain stem at this time. A different course of anesthesia by pentobarbital and urethane respectively correlated with this result: Only in the presence of urethane a persistent depression of spontaneous motility was seen, whereas the effectivity of both anesthetics on pinna and corneal reflexes and in respect of pentobarbital also on active movements occurrence declined in the end of the test period.
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PMID:[Relationships between course of anesthesia, depth of anesthesia and acetylcholine content of the brain after urethane and pentobarbital administration in the rat]. 98 27

Average acoustic-evoked responses (AAER) and EEGs were recorded from the lateral hypothalamus (LH), ventromedial hypothalamus (VMH), medial forebrain bundle (MFB) and reticular formation (RF) of freely behaving rats before and after various doses (0.2, 0.4, 0.8, 1.2 g/5g) of the anesthetic drug, urethane. The effect of a surgical level of urethane (1.2 g/5g) over time (8--14 h) was also studied. Urethane produced a dose-dependent slowing in the EEG frequency. The effect of 1.2 g/kg over time was a bimodal depression of the EEG frequency. Three components of the AAER were recorded consistently and evaluated in terms of amplitude. With increasing doses, the early component (P2) was depressed in the LH2, VMH and MFB, but not in the RF which remained at control values or higher. The later components (N2 and P2) were depressed in all four structures. This suggests that urethane may be blocking the integrative function of the RF, as well as in the thalamus, resulting in lower sensory input to higher CNS structures.
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PMID:Urethane modification of EEG-like activity and acoustically evoked field potentials recorded from deep nuclei. 108 2

Small lesions in the brain stem (including the hypothalamus) of the European hamster were effective with respect to food intake, hibernatory disposition and thermogenic power (oxygen consumption) as well. Hyperphagia was accompanied by depression of hibernation mostly. Moreover, hibernation was hindered by impairment of the thermogenic capacity. Entrance into hibernation depended on the integrity of the middle and caudal hypothalamic areas and the rostral portions of the pons and midbrain. Hyperphagia resulted from destruction of the middle (ventromedial) hypothalamic and caudal hypothalamic areas, including transition structures to the pons. A depression of thermogenesis against cold was observed after destruction of supramammillary and neighbouring mesencephalic areas. Supplementary results: An annual metabolic rhythm characterized by a minimum in december has been established once more. Urethane anesthesia did not abolish cold thermogenesis, despite the development of a slight hypothermia. Poikilothermia resulting from brain stem damage disappeared during a three-day period. Furthermore, diencephalic lesions did not suppress arousal from hibernation significantly.
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PMID:[Effect of brain stem lesions on hibernation of the hamster (Cricetus cricetus L.)]. 119 40

Na+ and Ca2+ currents were monitored using a suction electrode in unclamped presynaptic axons of rat olfactory cortex pretreated with 0.1 mM 3,4-diaminopyridine and 5 mM tetraethylammonium. The effects of anaesthetics on these currents were compared with tetrodotoxin or cadmium. Ketamine (0.1-1 mM), ether (20-200 mM), diisopropylphenol (0.01-0.5 mM) and lignocaine (0.01-0.2 mmol/l) all depressed both the initial Na+ component and the Ca(2+)-mediated tail of the response. Urethane (5-100 mM), halothane (1-5 mM) and pentobarbitone (0.1-2 mM) showed slight selectivity for the axonal Ca2+ tail. Diisopropylphenol apparently enhanced the Ca2+ tail at low concentrations. The alphaxalone (1-50 microM) depression was very weak. In a few cases the depression may contribute to anaesthesia but with others, high concentrations may contribute to the toxicity of the substances in vivo.
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PMID:Action of general anaesthetics on unclamped Ca(2+)-mediated currents in unmyelinated axons of rat olfactory cortex. 166 92

Urethane-anesthetized rats were used to study the mechanism of cocaine-induced death. Continuous recording of the changes in five physiological parameters, including respiratory rate (RR), electroencephalogram (EEG), blood pressure (BP), electrocardiogram (ECG), and body temperature (BT), were conducted after intraperitoneal (IP) administration of a single dose of cocaine HCl (70 mg/kg). In the control group (normothermic with core body temperature 37.7 +/- 0.1 degree C and spontaneously breathing), the death rate was 88% (15/17), and the average time to respiratory arrest was 12.99 +/- 1.40 min (mean +/- SEM). The first set of experiments investigated the contribution of hypothermia to cocaine-induced death. The hypothermic group (core body temperature 33.9 +/- 0.3 degrees C and spontaneously breathing) had a death rate of 81.5% (22/27), and an average time to respiratory arrest of 16.70 +/- 1.24 min, which was significantly (p les than 0.05) prolonged. A substantial decrease in respiratory rate was seen in normothermic group, while all the other measured parameters remained relatively stable until respiratory arrest. Sequential arterial blood gas data in this group showed a decrease in PaO2 from 116.0 +/- 5.7 mmHg to 57.7 +/- 4.6 mmHg, an increase in PaCO2 from 27.7 +/- 2.2 mmHg to 42.7 +/- 3.0 mmHg, and a decrease in pH from 7.467 +/- 0.039 to 7.357 +/- 0.003. To confirm that respiratory depression was an important mechanism of cocaine-induced death in this model, ten normothermic rats underwent mechanical ventilation, and all survived cocaine exposure. This study points to the important role of respiratory depression as a cause of cocaine-induced death.
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PMID:Cocaine-induced respiratory depression in urethane-anesthetized rats: a possible mechanism of cocaine-induced death. 178 91

1. We have investigated the influence of environmental temperature, anaesthesia and route of administration on rectal temperature and other metabolic responses to two preparations of bacterial endotoxin in male adult Wistar rats. 2. Urethane anaesthesia, environmental temperatures of 20 and 28 degrees C, subcutaneous (S.C.) and intraperitoneal (I.P.) routes of administration and butanol and trichloroacetic acid (TCA) extracts of E. coli endotoxin (1.2 mg/kg) were used. 3. In addition to rectal temperature, serum zinc, albumin and urea concentrations and liver protein, RNA and zinc contents were measured. 4. Fevers were produced by injections of both endotoxins, by either route at 28 degrees C. Butanol-extracted endotoxin produced a more rapid response than the TCA extract via the I.P. route whereas the TCA extract produced a higher temperature than the butanol extract when the S.C. route was used. 5. Fevers were inhibited at an environmental temperature of 20 degrees C and by anaesthesia, while the former had no effect on compositional changes the latter inhibited the fall in serum zinc in response to subcutaneous doses of either endotoxin and the increase in liver zinc content in response to the butanol extract of endotoxin. 6. At 20 degrees C a marked fall in rectal temperature occurred in conscious rats 2 h after receiving the TCA but not the butanol extract of endotoxin. Temperature depression was more severe when endotoxin was administered by the I.P. route. 7. Serum urea was elevated in conscious rats by the TCA extract of endotoxin via both routes but only by the I.P. route for the butanol extract of endotoxin. In anaesthetized animals only the TCA extract of endotoxin raised serum urea concentration when given intraperitoneally. 8. Serum albumin and liver protein and RNA were unaffected by endotoxin injections over the 7 h time course of the study. 9. Rectal temperature responses to endotoxins were influenced in direction and magnitude by all variables employed in the study, while compositional changes were unaffected by environmental temperature but influenced to varying degrees by urethane anaesthesia and the route of administration employed.
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PMID:Effects of urethane, ambient temperature and injection route on rat body temperature and metabolism due to endotoxins. 247 10

The anaesthetics described for use in hamsters to date are suitable for the performance of short-term experimentation. However, an anaesthetic regimen was required which would provide a stable preparation for 6 h and hence, a suitable combination was developed. In the first set of experiments, the effect of anaesthetics (chloralose, urethane, and pentobarbital) were examined alone and in combination on arterial blood measurements. In the second set of experiments the effect of the combination of anaesthetics on arterial blood measurements and minute ventilation was examined for up to 6 h. Chloralose, urethane and pentobarbital when used alone in the hamster were considered inadequate for our needs. Chloralose did not produce adequate surgical anaesthesia whereas urethane and pentobarbital resulted in marked respiratory depression. Urethane also produced a trend towards metabolic acidosis. In contrast, the combination of agents resulted in surgical anaesthesia and the arterial blood measurements were adequate. Further, the use of the combination of anaesthetics in hamsters resulted in a stable preparation where arterial blood measurements and minute ventilation were maintained in a good range for up to 6 h. The combination of chloralose, urethane and sodium pentobarbital in hamsters should prove useful in long-term non-recovery experimentation which requires early surgical intervention, minimal respiratory depression and an even depth of anaesthesia.
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PMID:An effective combination of anaesthetics for 6-h experimentation in the golden Syrian hamster. 270 95

Several thalamic nuclei are associated with the processing of pain information and are influenced by cortical actions. This paper demonstrates a cortical influence upon the medial thalamic nuclei unit activity evoked by thermal noxious stimulation in rats. We studied the effects of cortical spreading depression (CSD) upon the responses of the centralis lateralis (CL) nucleus of the medial thalamus to noxious heat stimulation. Urethane was used as anaesthetic. Cells responding to noxious stimulation were localized in the dorsal portion of the CL. These cells responded like polymodal or nociceptive specific units in the spinal cord and exhibited their highest discharge frequency with noxious stimuli. When CSD is propagated and affects the medial frontal cortex it blocks the responses evoked in CL cells by noxious stimulation. Cortical cells located at this level also exhibited responses evoked by noxious stimulation. Our results suggest a cortical facilitatory control upon the noxious responses recorded in the CL cells.
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PMID:Suppression of noxious thermal evoked responses in thalamic central lateral nucleus by cortical spreading depression. 323 33

1 The effect of thiopentone, methohexitone, urethane and ketamine on the uptake and release of gamma-aminobutyric acid (GABA) and D-aspartate by rat thalamic slices has been investigated. 2 A high, supra-anaesthetic concentration of methohexitone increased the uptake of both D-aspartate and GABA. 3 None of the anaesthetics used had any detectable effect upon the spontaneous release of either amino acid. 4 Urethane and ketamine had no effect upon the K+-stimulated release of either amino acid. 5 Methohexitone and thiopentone produced a biphasic dose-response on the K+-stimulated release of both amino acids; low concentrations enhanced release, high concentrations depressed release. 6 Bicuculline hydrochloride and picrotoxin both significantly reduced the barbiturate-induced enhancement of K+-stimulated amino acid release, but did not significantly alter the depression of K+-stimulated release at higher barbiturate concentrations. 7 Baclofen, either alone (1 microM to 1 mM), or tested against the barbiturates, had no detectable effect.
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PMID:The effects of anaesthetics on the uptake and release of amino acid neurotransmitters in thalamic slices. 612 80

Urethane (50 mM) produced a non-selective antagonism of depolarizations evoked by excitant amino acids or carbachol recorded from ventral roots of isolated spinal cord preparations of the frog or immature rat. Depolarizing responses to substance P or eledoisin-related-peptide were either unaffected or potentiated by this concentration of urethane. The threshold level for depression of dorsal to ventral root transmission was 10 mM urethane and transmission was completely blocked at 70-100 mM urethane. It is suggested that post-junctional blockade of the actions of excitant amino acids may be important in the anaesthetic action of urethane.
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PMID:Effect of urethane on synaptic and amino acid-induced excitation in isolated spinal cord preparations. 612 91


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