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Query: UMLS:C0278134 (anesthesia)
 110,339 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of taurine on the direct cortical response have been studied in immobilized cats (with local analgesia). The primary negative component of the response was inverted in polarity by the topical application of 25 mM taurine while the later slow negative component was considerably augmented. These effects are identical to those observed with 25 mM GABA. Pentobarbital anesthesia produced little qualitative change in the effects of taurine. With stronger stimuli in the presence of taurine, rhythmic waves followed each stimulus both at the cortical surface and at a depth of 1000 mum. An increase in the EEG amplitude following topical taurine was generally localized to the cortical surface but in certain experiments, could be recorded at cortical depths up to 1000 mum.
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PMID:Modification of the direct cortical response by taurine. 5 Feb 28

The mechanisms of petit mal epilepsy remain a mystery despite successful therapy. Previous workers have proposed that paroxysmal activity of cortical inhibitory systems plays a role in absence seizures. In this study, we have compared the effects of bicuculline, a potent convulsive agent and GABA antagonist, with ethosuximide, a drug used to treat petit mal epilepsy, on the thalamocortical motor system of the cat. Under chloralose anesthesia, sequential pairs of pulses were delivered to ventrolateral thalamus (VL) varying either pulse amplitude or interval. The evoked responses were recorded from sensorimotor cortex, analyzed on-line by computer, and plotted as an excitability curve (mean response amplitude as a function of pulse interval), or a family of threshold curves (mean response amplitude as a function of stimulus amplitude at various fixed intervals). Administration of each drug resulted in increased thalamocortical excitability and decreased threshold to stimulation for short pulse-pair intervals, with diminished duration of the excitability curve. Increased alertness was produced by both drugs. Studies with grand mal anticonvulsants demonstrated entirely different effects. Because GABA is thought to be the primary inhibitory transmitter in VL and cerebral cortex, bicuculline would be expected to result in disinhibition. The similarity of the data for ethosuximide suggests that ethosuximide also suppresses inhibition in the thalamocortical motor system and adds further to the accumulating evidence of the role of inhibitory system in petit mal epilepsy.
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PMID:Ethosuximide and bicuculline inhibition in petit mal epilepsy. 9 76

Major inhalational anesthetics cause inhibition in the electron transport chain in the region of Complex I resulting in decreased oxygen utilization, inhibition of metabolism of NAD-linked substrates, but not of succinate, inhibition of mitochondrial calcium uptake, and depression of synaptic transmission because of postulated changes in ACh sensitivity or GABA inhibition. Many cellular metabolic effects in CNS and other tissues are secondary to the above. Many metabolic changes noted with anesthetics occur subsequent to activation of the sympathetic nervous system either directly by the anesthetic or by surgical stimulation in the presence of light anesthesia. Many important studies remain to be done.
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PMID:Effects of anesthesia on intermediary metabolism. 16 50

The supraorbital branch of the trigeminal nerve of rats in chloralose anaesthesia was stimulated with electrical pulses. The stimulation of the afferent fibres of the trigeminal nerve evoked the retractive jerks of the outstretched tongue. These evoked tongue jerks (ETJ) were recorded on the tape of the line recorder through an isotonic transducer. The caniulae were inserted into the lateral cerebral ventricles by means of streotaxic apparatus and perfusion was performed with inflow of GABA or beta-phenyl-GABA-containing fluid into the right lateral ventricle and outflow through the left lateral ventricle. Perfusion with solution of 0.01 mol/l GABA reduced the amplitude of ETJ 25.9% while perfusion with hypertonic NaCl solution increased it by 19.5%, and perfusion with solution of 0.2 mol/l beta-phenyl-GABA reduced that amplitude by 39.9%.
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PMID:Inhibition of evoked tongue jerks during the rat's cerebral ventricles perfusion with gamma-aminobutiric acid and beta-phenyl-gamma-aminobutiric acid. 21 31

Mammalian spinal cord neurons were grown in dissociated cell culture and used to study the effects of the anticonvulsant barbiturates phenobarbital and mephobarbital, and the anesthetic barbiturates pentobarbital, secobarbital, and 1,3-dimethyl-butylethyl barbituric acid on amino acid responses and neuronal membrane properties. All barbiturates augmented responses to GABA and diminished glutamate (GLU) responses, but the anesthetic barbiturates were more potent. The anesthetic barbiturates directly depressed excitability by increasing membrane conductance, an effect reversed by the GABA antagonists picrotoxin and penicillin. Anticonvulsant barbiturates, however, had only minimal GABA-mimetic inhibitory action at high doses. Modulation of synaptic events mediated by GABA and GLU might contribute to barbiturate anticonvulsant activity; and direct GABA-mimetic inhibition, combined with similar modulation of synaptic transmission, might underlie barbiturate anesthesia.
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PMID:Anticonvulsant and anesthetic barbiturates: different postsynaptic actions in cultured mammalian neurons. 22 May 60

1. I. v. or i.a. injection of GABA produced a transient apnoea in rats under pentobarbital anaesthesia. The dose-response relationship and specifity of this effect were investigated. 2. Injection of GABA into the femoral vein led to an apnoea of dose-dependent duration, the dose-response curve showed an ED50 of about 5 mumoles GABA kg-1 and a maximum duration of about 8 s. 3. The depressant action of systemic GABA on respiration seems to be specific as only close structural analogues of GABA such as trans-4-aminocrotonic acid, beta-hydroxy-GABA, delta aminovaleric acid, beta-alanine, and taurine were able to mimic the action of GABA. 4. Injection of these structural analogues of GABA 15 s rior to an injection of GABA inhibited the respiratory depressant effect of GABA dose-dependently. Picrotoxin also antagonized the apnoic action of GABA. 5. The results indicate that the apnoea induced by systemic injection of GABA is mediated by an action on GABA receptors.
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PMID:Transient apnoea after systemic injection of GABA in the rat. 49 53

Male albino rats given a bilateral injection of Baclofen (Lioresal) (12 micrograms/rat) in the cerebral ventricles showed a behavioral syndrome of activation + ataxia, paddling, tail-pinch hyperresponse and anesthesia. The phase of activation + ataxia was reduced by pretreatment of rats with H 44/68, FLA 63, reserpine, pimozide, phenoxybenzamine, oxypertine or chlorpromazine. The phase of paddling was reduced by pretreatment with FLA 63, reserpine, phenoxybenzamine, oxypertine, chlorpromazine, pimozide + phenoxybenzamine or apomorphine, while administration of clonidine instead of Baclofen caused paddling in non-pretreated rats. The phase of tail-pinch hyperresponse was reduced by reserpine, oxypertine, chlorpromazine or pimozide + phenoxybenzamine, while none of the pretreatments affected Baclofen-induced anesthesia. Drugs which affect mainly tryptaminergic or GABA-ergic functions failed to affect Baclofen-induced behaviors consistently. The findings suggest that dopaminergic and noradrenergic functions play a role in the central effects of Baclofen on behavior of rats.
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PMID:The role of monoamines for the central effects of Baclofen on behavior of rats. 52 96

In experiments on newborn rabbits under nembutal (pentobarbital) anaesthesia, studies have been made on changes of visual evoked potential in the visual cortex during application of 1% solutions of GABA and nembutal. At the age of 7--9 days, these drugs decreased the evoked response, which may be associated with their hyperpolarizing effect on cortical synapses. Between the 11th and the 13th days, no effect of GABA and nembutal upon the evoked potential was noted. Definitive reaction to application of these pharmacological drugs typical for adult animals is formed not earlier than to the 15th--17th day. Beginning from this time, application of GABA and nembutal significantly increases visual evoked potential. The postnatal evolution of chemical sensitivity of postsynaptic membrane of neurons of the visual cortex in rabbits is discussed.
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PMID:[Change in the chemical sensitivity of the visual cortical synapses in rabbit ontogeny]. 67 84

Exogenous GABA administered into the lateral ventricle of the brain in Wistar rats in doses of 75, 200 and 600 microgram per rat, and endogenous GABA whose cerebral level was raised by intraperitoneal administration of hydroxylamine (Hx) in doses of 30, 50 and 75 mg/kg had a significant inhibitory effect on the central nervous system. This effect was abolished by bicuculine (Bc). The central effect of exogenous and endogenous GABA was manifested by reduced spontaneous and exploratory locomotor activity, decreased body temperature, potentiation of hexobarbital and chloral hydrate general anaesthesia and increase of haloperidol-induced catalepsy. On the other hand, no effect of GABA was observed on motor hyperactivity induced with amphetamine and on stereotypy induced with amphetamine and apomorphine.
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PMID:Central effects of endogenous and exogenous GABA. 70 39

A classical (Mendelian) genetic analysis of responses to eight sedative-hypnotic compounds (ethanol, urethane, trifluoroethanol, chloral hydrate, barbital, paraldehyde, methyprylon, pentobarbital) was conducted in crosses derived from mouse lines that were selectively bred for differential duration of anesthesia following ethanol. The sleep-time responses of these mice, the long-sleep (LS) and short-sleep (SS) mouse lines, as well as the F1, F2 and backcross (F1 x LS, F1 x SS) generations were measured. Generally, differences in responses among the generations were greater for water soluble compounds than were differences for more lipid soluble compounds. Also, the inheritance of responses to water soluble compounds could be explained primarily by additive effects of alleles while the inheritance patterns for more lipid soluble compounds were more complex. Genetic correlation with ethanol response decreased with increasing lipophilicity. These results suggest that the selection of the LS-SS mouse lines was specific for water soluble anesthetic agents. Because several of these agents are known to act at GABA receptors, examination of the interactions of compounds which differ in lipid solubility at GABA receptors from LS and SS mice may prove useful in elucidating the mechanism of the anesthetic actions of ethanol and other drugs.
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PMID:Classical genetic analyses of responses to sedative-hypnotic drugs in crosses derived from long-sleep and short-sleep mice. 135 60


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