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Biomedical subjects

A Wauquier

Publications and source records attributed to A Wauquier.

At least 19 recordsLinked to original sources
PubMed1979

Metrazol-produced impairment of passive avoidance retention specifically antagonized by anti-petit mal drugs.

In a single session, naive female 250-g Wistar rats were trained to remain for 3 min on a platform located above an electrifiable grid. During training, animals were shocked (4 mA) after they stepped down. Retention of the step-down avoidance was tested 24 h later in rats treated SC 30 min before the session with saline or a subconvulsive dose of metrazol (40 mg/kg). During the retention test no shock was delivered. The latency to step down and the time on the grid were recorded. The metrazol rats significantly failed to retain the avoidance task. Groups of six rats per dose were trained and 24 h later pretreated, 5 min before metrazol, with an IP injection of the following antiepileptics (dose range in mg/kg): Ethosuximide (20--320); trimethadione (20--320); clonazepam (0.04--0.63); sodium valproate (20--320); carbamazepine (1.25--20); phenobarbital (5--80); or diphenylhydantoin (5--80); or high dose of haloperidol (0.16) and amphetamine (0.63). Only ethosuximide, trimethadione, and clonazepam significantly increased the latency to step down and significantly shortened the time on the grid. Sodium valproate only shortened the time spent on the grid. The results suggest that only anti-petit mal drugs antagonize the retention impairment of passive avoidance produced by metrazol.

Animals↗
PubMed1979

Visual and computer-based analysis of 24 h sleep-waking patterns in the dog.

Sleep and waking EEG patterns recorded over 24 h periods in 7 adult beagle dogs were studied both visually and by computer. Online analysis was carried out using a mini-computer. The following quantitative data were computed and listed (and/or stored on disc) at 30 sec intervals: power spectrum analysis of one cortical derivation by means of Fast Fourier Transformation, the spectrum being divided in 4 bands (0.5-3.5, 3.5-7.5, 7.5-13.5, 13.5-25 c/sec); the power contained in the 3.5-7.5 c/sec band of the hippocampal derivation; a spindle detection algorithm empirically defined and based on the power contained in the 10.5-14.5 c/sec band of subepochs of 0.8 sec and the background power; average EMG and EOG amplitudes. Plots were made of the quantitative data (on the y axis) showing evolution with time (on the x axis). Comparisons with the y ordinates enabled a visual estimate of stage to be made. Automatic classification was done by means of minimal distance, using visually selected epochs and calculated parameters as references. Visual and computer-based analyses allowed the following patterns to be defined: wakefulness, transitional stage, light slow wave sleep, deep slow wave sleep and REM sleep. Sleep-waking cycles of 20-30 min alternated during the 24 h period with rapid transitions from one stage to another.

Animals↗
PubMed1979

Effects of some anti-epileptic, neuroleptic and gabaminergic drugs on convulsions induced by D,L-allylglycine.

The antagonism of various seizure and time-related components of the convulsions resulting after IV injection of D,L-allylglycine into male Wistar rats were assessed in a standard test procedure. Trimethadione and ethosuximide did not antagonize the seizure components, whereas clonazepam, phenobarbital, diphenylhydantoin, primidone, valproate sodium, aminoxyacetic acid, etomidate, acetazolamide, flunarizine, pipamperone and baclofen did. The allylglycine test may thus represent a relatively specific method of differentiating between drugs effective against partial or generalized convulsive seizures from those effective against absence seizures. The neuroleptics haloperidol and pimozide were completely inactive in contrast to their reported antagonism of bicuculine seizures. The spectra of the active substances are discussed with respect to Principal Component and Cluster Analysis. Noteworthy are the similarities between baclofen and etomidate; between aminoxyacetic acid, phenobarbital and valproate sodium; and between diphenylhydantoin and flunarizine.

Allylglycine↗
PubMed1979

A comparison between lick or lever-pressing contingent reward and the effects of neuroleptics thereon.

Rats implanted with an electrode in the lateral hypothalamus were trained to obtain brain-stimulation by either pressing a lever or by licking a steel drinking tube in subsequent 15-min sessions. Half of the rats began the sessions with lever-pressing, the other half began with licking. After stabilization of the response rates, rats were run in saline- or drug-sessions. During the drug sessions rats were treated with 4 doses of the following neuroleptics: haloperidol, pimozide, pipamperone, azaperone. These neuroleptics dose-relatedly inhibited licking for brain-stimulation but suppressed lever-pressing only at the highest dose tested. The lick response was thus inhibited at lower doses than lever-pressing. This differential sensitivity to neuroleptics appears not to be due to a difference in baseline response rates, schedule differences or to the motor activity involved in both responses, but rather to the different thresholds of reinforcement produced by licking and lever-pressing for brain-stimulation.

Animals↗
PubMed1979

Arterial blood pressure and heart rate changes during self-stimulation by dogs in the basal forebrain region, lateral preoptic area, hypothalamus, ventral midbrain and amygdala.

In dogs pressing a lever for a brain-stimulation reward, arterial blood pressure (ABP) was elevated for 20 out of 24 sites tested, but this effect was usually conspicuous only at twice the threshold current sustaining stable performance. Hypertension was seen only in one ventral tegmental and two hypothalamic sites. In three anterior placements the ABP and heart rate (HR) increased more upon a fixed ratio than on continuous reinforcement. In most sites, self-stimulation was accompanied by cardiac acceleration; however, in some placements the HR was similar to or even less than control values. Continuous stimulation (5-10 sec) at one nucleus accumbens and four hypothalamic sites by the experimenter was aversive and produced a clearcut pressor response. The cardiovascular changes seem to depend on a spread of current to brain centres controlling circulatory functions and also, to some extent, on the animal's motor activity. The results contradict the claim that a causal relationship exists between the autonomic concomitants of self-stimulation and the intrinsic nature of the brain-stimulation reward.

Amygdala↗
PubMed1978

A putative multipartite model of haloperidol interaction in apomorphine-disturbed behavior of the dog.

The interaction between various doses of apomorphine and haloperidol on intracranial self-stimulation in the dog was studied using a pradigm in which reinforcing brain-stimulation was controlled by a discriminative auditory stimulus. Reinforced lever-pressing was decreased by low doses of apomorphine and completely suppressed by stereotypogenic doses. At various doses of apomorphine, low doses of haloperidol either increased response inhibition by enhancing stereotypy, or increased lever pressing by reducing stereotypy while concomitantly increasing the number of nonreinforced responses. Intermediate to relatively high doses of haloperidol antagonized stereotypy and the response inhibition produced by apomorphine. High doses of haloperidol antagonized stereotypy but also suppressed self-stimulation. Thus, haloperidol is not only able to restore performance capability, but also disturbed reinforcing and discriminative stimulus control.

Animals↗
PubMed1978

Electroencephalographic study of the short-acting hypnotics etomidate and methohexital in dogs.

Beagles, implanted with cortical and subcortical electrodes, were given etomidate i.v. (1 mg/kg) over a period of 10 sec. The effects on the EEG were compared with those obtained with 7 mg/kg of methohexital. Both compounds induced hypnosis for a duration of approximately 8 min. The EEGs showed a remarkable similarity. Visual inspection of the records as well as power spectrum analysis revealed a sustained theta-activity with underlying fast activity. The configuration of the waves was rather sharp. The power obtained after etomidate was, however, 2 to 3 times that obtained after methohexital. When the animals awoke from etomidate-induced hypnosis slow waves appeared and were followed by alpha-activity, whereas after methohexital-hypnosis beta-activity predominated. Etomidate slightly increased heart rate, but respiratory depression was not observed. Methohexital caused pronounced tachycardia and apnoea. In 3 out of 6 dogs methohexital caused myoclonus of the hind legs upon awakening from anaesthesia. Etomidate induced myoclonus in one dog during hypnosis.

Animals↗
PubMed1976

Intracranial self-stimulation in rats as a function of various stimulus parameters. VI. Influence of fentanyl, piritramide, and morphine on medial forebrain bundle stimulation with monopolar electrodes.

The effects of different subcutaneous doses of fentanyl (0.02, 0.04, 0.08, and 0.16 mg/kg), piritramide (0.63, 2.50, 10.0 and 40.0 mg/kg), and morphine (2.50, 5.00, 10.0 and 20.0 mg/kg) on self-stimulation in rats were studied. Different stimulus parameter combinations (SPC) inducing low, high or intermediate control response rates (CRR) were applied during the same experimental sessions. The three narcotic analgesics induced response depression (RD) and response stimulation (RS). RS was mostly observed at low dose levels; RD was dose-related. SPC's inducing low CRR were more sensitive than those inducing high CRR. Fentanyl was more potent than piritramide and than morphine. The RD is related to motor incapacitation, as the doses needed to effectively reduce self-stimulation also induced obvious catatonia. The RS probably is a more specific effect reflecting sensitization of structures involved in reinforcement of behavior.

Analgesics, Opioid↗
PubMed1976

Restoration of self-stimulation inhibited by neuroleptics.

Pimozide-induced inhibition of lever-pressing for brain stimulation in the lateral hypothalamic area was differentially restored by the centrally acting anticholinergic, dexetimide and by different dopaminergic drugs. In addition, a differential antagonism towards chlorpromazine-induced inhibition of self-stimulation was shown. The results indicate that anticholinergis (non-competitive antagonism) or drugs which enhance endogenous neuro-transmission by increased release or by uptake blockade (competitive antagonism) are able to reserve the neuroleptic-induced inhibition of self-stimulation more effectively than are receptor agonists.

Amphetamine↗
PubMed1976

Bromperidol, a new potent neuroleptic of the butyrophenone series. A comparison of the effects of bromperidol and haloperidol in intracranial self-stimulation.

Bromperidol, a new potent and long-acting neuroleptic of the butyrophenone series, and haloperidol were injected s.c. at the doses 0.01, 0.02, 0.04 and 0.08 mg/kg, in rats implanted with electrodes in the lateral hypothalamic region of the medial forebrain bundle. A dose-related response inhibition was found with both compounds and the graphically estimated ED50 value was 0.041 mg/kg for bromperidol and 0.047 mg/kg for haloperidol. These data are in complete agreement with our previous findings that bromperidol is a new potent and specific neuroleptic.

Animals↗
PubMed1975

Differential antagonism by the antichlolinergic dexetimide of inhibitory effects of haloperidol and fentanyl on brain self-stimulation.

Haloperidol (0.08 mg/kg) or fentanyl (0.16 mg/kg) injected subcutaneously suppressed bar-pressing for brain-stimulation in rats, implanted with electrodes in the lateral hypothalamic area of the medial forebrain bundle. Increasing doses: 0.04, 0.16, 0.63 and 2.50 mg/kg of the central anticholinergic dexetimide gradually antagonized the haloperidol effects. The highest dose of dexetimide did not reduce the fentanyl-induced inhibition. The results, together with a literature survey on the anticholinergic effects on neuroleptic-induced catalepsy and inhibition of avoidance behavior, are related to biochemical findings and clinical effects.

Animals↗