Acute alcoholic intoxication and naloxone. Effects on visual evoked potential.

Experimental assays analyzing visual evoked potential (VEP) changes during an acute alcoholic intoxication were carried out in two groups of cats: One with continuous ethanol (0.06 g/kg.min) i.v. perfusion. Another one with a naloxone (400 micrograms/kg) i.v. injection 10 min before ethylic perfusion. Naloxone potentiates alcohol effects on VEP parameters, and on the appearance of isoelectric postpotential and flat VEP.

Report of a case: acromesomelic dysplasia: radiologic, clinical, and pathological study.

We report a 51-year-old woman with acromesomelic dysplasia. Pathologic studies on adult bone are reported. Hydrocephalus and mild oligophrenia are additional findings.

Effect of naloxone on acute ethylic intoxication. An EEG study.

EEG recording has been used to evaluate in cats the effect of naloxone on acute ethylic intoxication (AEI). Naloxone was administered both before and during the course of AEI. Results of the experiment showed that administration of naloxone before the AEI potentiates the toxic effect of alcohol. However, the administration of naloxone in a continuous way along the course of AEI significantly diminished the toxic effect of alcohol.

Electroencephalographic study of naloxone effects in the recovery of an acute alcoholic intoxication.

Experimental assays analysing EEG changes during the recovery of an acute alcoholic intoxication were carried out in three groups of cats: 1) Recovery of acute alcoholic intoxication produced by continuous intravenous perfusion of ethanol, 0.06 g/kg/min, during 20 minutes. 2) Recovery of acute alcoholic intoxication by injecting naloxone (400 micrograms/kg), just after finishing alcohol perfusion. 3) Recovery of acute alcoholic intoxication by injecting naloxone (400 micrograms/kg), 15 min after finishing perfusion. Naloxone administered after an acute alcoholic intoxication worsens the recovery of EEG parameters; 1-2 (p less than 0.05), 1-3 (p less than 0.05).

[Experimental visual evoked potentials. Interstimuli interval and cortical excitability]. / Potencial evocado visual experimental. Intervalo interestímulos y excitabilidad cortical.

The excitability of the visual system was studied in ten adult chronic cats. Visual evoked potentials were recorded, using decreasing interstimulus intervals. A decrease of the excitability of the visual system is observed when interstimulus intervals are less than 800 milliseconds. Clinical applications with regard to visual evoked potential recording on comatose patients are suggested.

Pharmacology of acute alcoholic intoxication.

Research of the alcohol action mechanism on the SNC in acute alcoholic intoxication (AAI) has been dealt in various ways. On one side the alcohol action--apparently most unspecific--on cellular membranes has been studied. Other authors, instead, have studied more specific alcohol effects on three types of neurotransmitters: opioid peptides, GABA and catecholamines. The effect of alcohol on cellular membranes seems to be beyond any doubt. Alcohol action on specific neurotransmitters is the object of controversy, especially in the case of endogenous opioids. There are data which strongly support the participation of the GABA receptors in the AAI. Modifications produced in the cellular membrane by alcohol action can modify the structure of the function of the membrane receptors. On the other hand, distinct receptors may be localized in the same neuron, while the existence of interactions between different neurotransmitters is well known. Therefore, the various hypotheses previously stated are not mutually exclusive.

[Representation of physiologic functions in the modulation domain ]. / Representación de funciones fisiológicas en el Dominio de la Modulación.

The axes: amplitude, frequency, time, define a trihedral where the most usual representations occur in time domain (plane defined by the axes amplitude-time). The frequency of an action with respect to time is represented in the plane defined by the axes frequency-time in the so called "Modulation Domain", it is being considered very useful, expressive and easy to construct in the automatic treatment of signals.

[Experimental conditions which modify the visual evoked potential]. / Condiciones experimentales que modifican el potencial evocado visual.

The effect of the visual stimulus intensity on the latency and morphology of the visual evoked potential (VEP) components is studied in cats with chronic implanted electrodes. A lessening in the luminous stimulus intensity is observed to produce a progressive diminution in the amplitude of the initial waves of the VEP till its disappearance, as well as a progressive increase in the latency, following an exponential function. Since the integration in a cortex zone is achieved by pathways of various lengths, the impulses arrive with different delays. It is suggested that stimuli of little intensity generate trains of impulses whose integration, in a small cortex area, is likely characterized by a delay in the appearance of high relative frequencies; whereas high intensity stimuli are more likely to produce high frequencies, in the same cortex area, and with earlier appearance. This may be considered as the explanation for the delay of analogous waves generated by stimuli of lesser intensity.