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Biomedical subjects

J Jiménez-Vargas

Publications and source records attributed to J Jiménez-Vargas.

At least 19 recordsLinked to original sources
PubMed1992

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.

Acute Disease↗
PubMed1989

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.

Animals↗
PubMed1989

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).

Alcoholic Intoxication↗
PubMed1989

[Experimental conditions which modify the visual evoked potential].

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.

Animals↗
PubMed1986

[Endogenous opioids in respiratory inhibition by laryngeal stimulation].

The reflex effect elicited by mechanical stimulation of the glottis has been studied in dogs. The three components of the response--sudden apnea, constriction of the glottis and bradycardia--were modified by naloxone, although not in the same degree. These results suggest the existence of opioid interneurons between laryngeal afferent fibers and central inspiratory neurons.

Animals↗
PubMed1986

[Apneic laryngeal chemoreflex and naloxone].

The apneic laryngeal chemoreflex (QRL), elicited by water on the vocal cords and by mechanical stimulation (MRL) has been compared in dog. Both stimuli cause apnea, bradycardia, hypotension and constriction of the glottis. In QRL apnea predominates white in MRL bradycardia is more intense. All the components of the response decrease with naloxone at a 400 micrograms X kg-1 doses, suggesting that the reflex inhibition depends on endogenous opioids located in the respiratory centre.

Animals↗
PubMed1985

[Respiratory effects of naloxone].

The respiratory effects of naloxone (200 micrograms X kg-1) on dogs, was studied measuring the parameters breath rate, inspiratory volume, breath minute volume, inspiratory time, total time of cycle, inspiratory volume/inspiratory time ratio, and inspiratory time/total time of cycle ratio. The statistical study was made by using the analysis of variance. Naloxone increases all the parameters studied as well as the response to CO2 while it decreases inspiratory time. The results suggest that there are opioid neurons in the respiratory centre. The blockade of the opioid receptors by naloxone almost explains the respiratory effects observed.

Animals↗
PubMed1985

[Effect of naloxone on coughing].

Naloxone at doses of 200 micrograms X kg-1 increases cough, in experiments carried out on dogs. With stimuli of the same intensity, after naloxone, a significant increase in the number of coughs in each fit, is observed. Changes in the first cough burst, compared with spontaneous respiration at rest, are statistically significant and they contribute to define the characteristics of the cough burst. The increase of cough by naloxone blockade of endorphinic neurons of the respiratory center shows that usually the activity of these inhibitory neurons, tonically depresses the tussive response. The antitussive opiates would seem to operate by activating these inhibitory synapses.

Animals↗
PubMed1981

[Effect of copulation on the follicular development and ovulation in rat (author's transl)].

The follicular development, ovulation and position of the oocytes in the stretched tubes at different phases and times of the rat's ovarian cycle, and the effect of different conditions of copulation on these processes have been studied. With copulation from the 16th hour of diestrus to the 16th hour of proestrus, the number of large follicles, follicles total, and oocytes plus follicles increased significantly. With copulation from the 10th hour of proestrus to the 10th hour of estrus, the number of oocytes, small follicles and follicles total increased significantly. Copulation, therefore, facilitates the processes of follicular development and ovulation.

Animals↗
PubMed1979

[Modification of the ovarian cycle, ovulation and reproduction in rat by administration of p-chlorophenylalanine in the pre and post ovulation period (author's transl)].

The effect of p-Chlorophenylalanine (PCPA) administered in pre and post-ovulation phases on ovulation reproduction and ovarian cycle was studied in rats. Vaginal smears, number of ovules, mature follicles and ovaric histologic features were evaluated. PCPA administered in the periods after follicular rupture prolongs the diestrus phase from 2 to 10 consecutive days and totally inhibits the reproductive conduct. When administered in the periods just prior to follicular rupture, PCPA prolongs the estrus phase from 2 to 4 consecutive days and does not totally inhibit reproduction. A progressive increase in reproduction took place as treatment time approached ovulation, to such an extent that the number of inseminated and fertilized rats when treated at the ninth hour of the proestrus phase, was superior to the control group. PCPA administered in periods after and before follicular rupture totally inhibits ovulation in all cases. Ovaries present many mature follicles, as many as in the controls sacrificed at the 18 hour of the proestrus, just before ovulation.

Animals↗
PubMed1979

[Supression by copulation of the inhibitory effect of p-chlorophenylalanine on rat ovulation (author's transl)].

The effect of copulating on reflex ovulation was studied in rat. The effect of PCPA (300 mg/kg, i.p.) on ovulation and reproduction was compared by evaluating number of oocytes in tubes, histologic features of ovaries, vaginal cycle, insemination, fertilization and number of embryos per rat. PCPA, administered on 9th and 16th h of the estrus phase, totally inhibits ovulation, stimulates reproductive behaviour and prolongs the estrogenic phase. When the animals are kept in copulatory conditions for 16 or 46 hours, the inhibition induced in ovulation disappears to the extent that 60% of the rats become pregnant though the number of embryos is under that of the control group. The farther the treatment with PCPA within the same cycle in the ovulatory period, the greater the inhibitory effect on ovulation is and the lesser the neutralizing effect produced by reflexes related to copulation. Administration of PCPA at the 16 hour of the diestrus causes a greater increase in the average number of embryos-as compared to administration at the 9 hour. In periods longer than 48 hours before ovulation, the inhibition brought about by PCPA is not suppressed by copulatory conditions kept for 16 or 24 hours and is only neutralized if they are kept during a complete cycle. Those treated with PCPA in the diestrus phase and maintained in copulatory conditions for 46 hours, present a higher average of embryos than those maintained in similar conditions for 16 hours.

Animals↗
PubMed1978

[Reflex factors that modify the effect of p-chlorophenylalanine on ovulation and reproduction in rats (author's transl)].

The appearance of reflex ovulation in rats under the influence of the copulation, has been studied. Evaluation of insemination, fecundation, number of embryos, ovarian cycle and ovulation in several groups of rats treated with doses of p-CPA (300 mg/Kg, i.p.), have been made. The application of p-CPA 48 hours before the estrus phase, inhibits the ovulation. This increases significantly through copulation. Reproduction is totally inhibited by p-CPA in animals under copulation conditions during 24 hours of the estrus phase. The inhibition is desappears if placed under copulation conditions during a full cycle. Inseminated rats had a 33% decrease in number of embryos with respect to the control group. The application op-CPA 24 hours before the estrus phase does not produce any inhibition effect. The decrease observed in the number of embryos is non-significant. When p-CPA is applied, instead, 48 hours before the estrus phase, there is total inhibition of the reproductive conduct.

Animals↗
PubMed1976

[Serotoninergic mechanisms in ovarian cycle (author's transl)].

Influence of 5-HT on the rat follicle rupture mechanism was studied by the administration of p-clorophenyl-alanine (p-CPA) (300 mg/kg) at different stages of the ovarian cycle. The ovarian cycle of treated rats was subject of investigation, as well as the histology of tubes and ovaries. Administration of p-CPA at 10 hours of metestrus phase induces an inhibition of ovulation. Predominant diestrus phases in the ovarian cycle and luteinitation of ovaries suggested an increase in progesterone secretion probably owed to a correspondingly greater prolactine secretion. Adequate 5-HT levels in central structures proved to necessary for normal ovulation.

Animals↗
PubMed1976

[Effect of p-chlorophenylalanine on rat reproduction under different conditions of lighting (author's transl)].

Reproduction in female rats kept on artificial cycles of light/darkness, continuous lighting and continuous darkness, has been studied. Three weekly doses of p-chlorophenylalanine (p-CPA), 100 mg/kg, were given to half of the rats in each group during the two preconditioning months before copulation. An evaluation has been made of the insemination, fecundation, number of embryos, ovarian cycle and level of 5-HT in the hypothalamus. The administration of p-CPA had an inhibitory effect on the reproductive behavior, especially pronounced in rats kept under continuous lighting and under continuous darkness. The difference in 5-TH levels were greater among the groups kept on cycles of light/darkness without treatment and with p-CPA (0.05 greater than P greater than 0.01). The importance of 5-HT in the mechanisms of reproductive behavior is emphasized.

Animals↗
PubMed1975

[Effect of 6-hydroxydopamine intracerebrally injected on reproduction in rats (author's transl)].

The effect of 6-hydroxidopamine (6-OH-DA) --250 mug-- intracerebrally injected on rat ovulation has been studied. Administration of 6-OH-DA in the nucleus accumbens septi and its heigbhourhood, inhibited follicle rupture, causing ovarian cycles with leucocitary phases in nearly all cases. The ovaries present a deep lutteynitation. Administration of 6-OH-DA in the strio-hypothalamic tract gives rise to a estrogenic cycle and to a normal number of oocytes in the tubes. The study of the fibrillar degeneration leads us to assumption of a probable adrenergic connections of the nucleus accumbens septi with the lateral hypothalamic area, preoptic area and olfactory tubercule. The influence of the nucleus accumbens septi on the mechanisms of follicle rupture is stressed.

Animals↗
PubMed1975

[Effect of p-chlorophenylalanine on the reproduction of the rat (author's transl)].

The effect of p-chlorophenylalanie (p-CPA) --300 mg/kg-- on reproduction has been studied in the female rat. Groups of animals were injected with a dose of 300 mg/kg of p-CPA 48 hours before proper copulation conditions at different moments along the ovarian cycle. Presence of spermatozoa in the vaginal frotis was negative in treated rats; in the control groups however, positivity was found in variable proportions according to the phase of the ovarian cycle: 30 ad 90% in diestrus and proestrus respectively. Treated animals showed continuous diestrus phases and diffuse luteinitation of the ovary. The results may indicate that a decrease of cerebral 5-HT, caused by p-CPA, lessens the reproductive behaviour of the female rat through mechanisms depending probably on the liberation of gonadrotrophins.

Animals↗
PubMed1975

[Serotoninergic and adrenergic factors influencing the ovulation and reproduction in the rat].

The action of 5-hydroxytryptamine (5-HT) on ovulation and reproduction in female rats with unique or repeated treatments of p-chlorophenylalane (p-CPA) was studied under different conditions of illumination. Histological studies were carried out on the tube and ovaries, controls of the ovarian cycle and of inseminations produce by vaginal deposits. An evaluation has been made of the insemination, fecundation, number of embryos, ovarian cycle and in anothers series hypothalamic determinations of 5-HT were carried out. In one group of rats the effect of intracerebrally administration (n. accumbens septi) 6-hydroxydopamine (6-OH-DA) (250 mug) on ovulation was studied. The administration of a unique doses of p-CPA (300 mg/Kg) induces an inhibition of the reproductive cycle in all its phases and in all the rats. Which repeated doses (100 mg/Kg) reproduction was inhibited in rats maintained under continuous illumination and under continuous darkness. Ovulation studies revealed that follicle rupture, was inhibited with a unique dose of p-CPA (300 mg/Kg). The histological study showed, marked luteinitation of ovaries. The ovarian cycle after a unique dose of p-CPA showed continuous diestrus phases. The results may indicate that a decrease of cerebral 5-HT producing a hormonal change which leads to the disappearence of the oestrogenic phase, with consequent inhibition of rupture and decrease in receptivity of the female rat. The administration of 6-OH-DA in the n.accumbens septi inhibited follicle rupture giving rise to manifest lutteynitation. A further study on the degeneration of nerve fibres, suggests the posssibility of adrenergic influence in ovulation of septal structures.

Animals↗